——————————————
Microsoft Windows Millennium Edition
Ayuda para el disco de inicio de emergencia
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(c) Copyright Microsoft Corporation, 2000
Este documento proporciona informaciўn complementaria o de Јltima hora
como suplemento a la documentaciўn de Windows Millennium Edition
(Windows ME).
Para cerrar este archivo de Ayuda, presione ALT-A-S.
———
CONTENIDO
———
RESUMEN
Si Windows Millennium Edition Јnicamente se inicia en el modo
a prueba de errores
TIPOS DE MђTODOS Y MEDIOS DE INSTALACION DE WINDOWS MILLENNIUM EDITION
Windows Millennium Edition (versiўn comercial)
Windows Millennium Edition (versiўn de actualizaciўn)
Cўmo busca las versiones anteriores de Windows el programa de instalaciўn
de la versiўn de actualizaciўn de Windows Millennium Edition
Instalaciones limpias
Versiones OEM de Windows Millennium Edition
SI WINDOWS MILLENNIUM EDITION NO SE INICIA EN EL MODO A PRUEBA DE ERRORES
Usar ScanDisk para comprobar el disco duro
Usar el Comprobador del Registro de Windows
SI EL PROGRAMA DE INSTLACION SE DETIENE Y WINDOWS MILLENNIUM EDITION NO SE
INICIA EN EL MODO A PRUEBA DE ERRORES
Aviso acerca del software antivirus
El programa de instalaciўn deja de responder durante la detecciўn de
hardware
DESINSTALAR WINDOWS MILLENNIUM EDITION
INSTALAR WINDOWS MILLENNIUM EDITION CON WINDOWS NT O WINDOWS 2000
INSTALAR WINDOWS MILLENNIUM EDITION EN UN DISCO DURO NUEVO
=======
RESUMEN
=======
Si tiene problemas para instalar o iniciar Windows Millennium Edition
intente iniciar el equipo en el modo a prueba de errores antes de
intentar los pasos que se indican en este documento.
Si puede iniciar el sistema en el modo a prueba de errores, consulte
el Solucionador de problemas de modo a prueba de errores de Windows
Millennium Edition, en la p gina de advertencia de Modo seguro.
En el modo a prueba de errores, puede utilizar las herramientas de
resoluciўn de problemas de Windows, como Restaurar sistema, que no
est n disponibles al iniciar el equipo desde este disco de inicio.
Para iniciar Windows en modo a prueba de errores:
1. Extraiga el disco de inicio y reinicie el equipo.
2. Cuando arranque de nuevo el equipo, presione la tecla CTRL
y mant‚ngala asЎ hasta que aparezca el menЈ de inicio de
Microsoft Windows Millennium Edition.
3. En el menЈ Inicio, elija Modo a prueba de errores (opciўn 3).
4. Siga los pasos que se indican en el Solucionador de problemas del
modo a prueba de errores.
Si Windows Millennium Edition Јnicamente se inicia en el
modo a prueba de errores
———————————————————
Si siguiў los pasos indicados en el Solucionador de problemas del
modo a prueba de errores y, aЈn asЎ, no puede iniciar Windows con
normalidad, siga estos pasos:
1. Cierre este archivo de Ayuda.
2. En el sЎmbolo del sistema, escriba:
scanreg /restore
y presione ENTRAR.
3. Seleccione la fecha de copia de seguridad mas reciente y, a
continuaciўn, haga clic en Restaurar.
Si realiza estos pasos y sigue sin poder reiniciar el equipo
con normalidad:
1. Utilice el disco de inicio de Windows Millennium Edition para
reiniciar el equipo y seleccione la opciўn 1 en el menЈ de
inicio y, a continuaciўn, haga presione ENTRAR.
2. Cierre el archivo de Ayuda.
3. Siga las instrucciones que aparecen en la pantalla para intentar
instalar de nuevo Windows Millennium Edition.
**********
IMPORTANTE: Si instalў algЈn programa incluido con su disco duro,
asegЈrese de leer la documentaciўn que describe cўmo iniciar el
equipo con un disco de inicio.
**********
======================================================================
TIPOS DE MђTODOS Y MEDIOS DE INSTALACION DE WINDOWS MILLENNIUM EDITION
======================================================================
La siguiente secciўn describe las diferentes versiones de Windows
Millennium Edition y sus requisitos de instalaciўn.
Windows Millennium Edition (versiўn comercial)
———————————————-
Esta versiўn no requiere una versiўn anterior de Microsoft Windows.
Windows Millennium Edition (versiўn de actualizaciўn)
——————————————————
El programa de instalaciўn requiere una copia anterior de
Microsoft Windows 95 ў Windows 98.
Cўmo busca las versiones anteriores de Windows el programa de instalaciўn
de la versiўn de actualizaciўn de Windows Millennium Edition
—————————————————————————
El programa de instalaciўn busca en su equipo un producto que le permita
realizar la actualizaciўn. Si el programa de instalaciўn no encuentra una
versiўn anterior de Windows en su equipo, le pedir que inserte el medio de
la versiўn anterior para confirmar que puede realizar la actualizaciўn.
El medio puede ser un CD-ROM, un disco o una carpeta del disco duro en la
que se encuentren los archivos de instalaciўn. Si utiliza discos, el
programa
de instalaciўn podrЎa pedirle varios de ellos.
Instalaciones limpias
———————-
Puede utilizar la versiўn de actualizaciўn de Windows Millennium Edition
para instalar Windows Millennium Edition en un equipo que no tenga
instalada
una versiўn anterior de Windows, como sucede despu‚s de formatear el disco
duro. Esta opciўn se suele denominar «instalaciўn limpia».
Como el proceso de comprobaciўn de conformidad no puede encontrar una
versiўn
anterior, el programa de instalaciўn le pedir que inserte el medio de la
versiўn anterior para confirmar que puede realizar la actualizaciўn.
El medio puede ser un CD-ROM, un disco o una carpeta del disco duro en la
que
se encuentren los archivos de instalaciўn. Si utiliza discos, el programa
de
instalaciўn podrЎa pedirle varios de ellos.
Para obtener mas informaciўn acerca de cўmo instalar Windows Millennium
Edition en un equipo en el que no haya un sistema operativo anterior,
consulte
«Cўmo instalar Windows Millennium Edition en un disco duro nuevo», al final
de este
documento.
Versiones OEM de Windows Millennium Edition
——————————————-
La versiўn de Windows Millennium Edition para fabricantes de equipos
originales
(OEM) es una versiўn comercial especial a disposiciўn de los fabricantes de
equipos. Los OEM pueden personalizar estas versiones de Windows
Millennium Edition para su hardware y software.
Los procedimientos y requisitos de instalaciўn que se describen en este
documento pueden ser diferentes si dispone de una versiўn OEM de Windows
Millennium Edition. Para obtener mas informaciўn, lea la documentaciўn
incluida con su equipo o pўngase en contacto con el fabricante del mismo.
=========================================================================
SI WINDOWS MILLENNIUM EDITION NO SE INICIA EN EL MODO A PRUEBA DE ERRORES
=========================================================================
Las siguientes condiciones pueden hacer que Windows Millennium Edition
no se inicie en el modo a prueba de errores:
— El equipo fue infectado por un virus. Utilice software antivirus
actualizado para comprobar si hay un virus y limpiar el equipo si
es necesario.
— La configuraciўn del CMOS del equipo no es correcta. Compruebe si
la configuraciўn del CMOS del equipo es correcta. Tenga en cuenta
que puede necesitar ponerse en contacto con el fabricante del
equipo para comprobar la configuraciўn.
— Existe un error en el hardware. Tenga en cuenta que puede necesitar
ponerse en contacto con el fabricante del equipo para obtener mas
informaciўn acerca del hardware.
— Existe un error en el disco duro del equipo. Consulte «Usar ScanDisk
para comprobar el disco duro».
— Existe un error en el Registro de Windows. Consulte «Usar
el Comprobador del Registro de Windows».
Usar ScanDisk para comprobar el disco duro
——————————————
Si cree que existen da¤os en algЈn archivo o algЈn problema de otro tipo
en su disco duro, ejecute ScanDisk para comprobarlo y reparar los errores.
Para comprobar en todos los discos duros si hay errores:
1. En el sЎmbolo del sistema, escriba:
scandisk /all
2. Presione ENTRAR.
Para realizar una comprobaciўn de superficie completa en todos los
discos duros y conseguir la m xima protecciўn ante la p‚rdida de datos:
1. En el sЎmbolo del sistema, escriba:
scandisk /all /surface
2. Presione ENTRAR.
Usar el Comprobador del Registro de Windows
——————————————-
Si aЈn asЎ no puede iniciar Windows Millennium Edition en el modo
a prueba de errores, ejecute l Comprobador del Registro de Windows
(Scanreg.exe), ya que podrЎa haber un problema en el Registro de
Windows.
Para iniciar el Comprobador del Registro de Windows:
1. En el sЎmbolo del sistema, escriba:
scanreg /restore
2. Presione ENTRAR.
Es posible que Scanreg no est‚ disponible si Windows Millennium Edition
no se instalў correctamente en el equipo.
=========================================================================
SI EL PROGRAMA DE INSTLACION SE DETIENE Y WINDOWS MILLENNIUM EDITION NO SE
INICIA EN EL MODO A PRUEBA DE ERRORES
=========================================================================
La siguiente secciўn explica lo que puede hacer para recuperar la
instalaciўn de Windows despu‚s de un error. Para obtener mas informaciўn
acerca de otros problemas de instalaciўn, consulte el archivo instalar.txt
que encontrar en la carpeta Win9X del CD de Windows Millennium Edition.
Si encuentra alguno de estos mensajes de error al ejecutar el programa de
instalaciўn:
— Disco de sistema no v lido
— Versiўn incorrecta de MS-DOS
— El archivo Command.com est da¤ado o no se encuentra
es probable que deba actualizar los archivos del sistema en el disco de
inicio de su equipo. Algunas opciones de configuraciўn del CMOS o
software antivirus pueden impedir que el programa de instalaciўn de
Windows instale en su equipo los archivos de sistema correctos.
Para sustituir los archivos de sistema:
1. Utilice el disco de inicio de Windows Millennium Edition para
reiniciar el equipo y seleccione la opciўn 1 en el menЈ de
inicio y, a continuaciўn, haga presione ENTRAR.
2. Cierre el archivo de Ayuda.
3. Siga las instrucciones que aparecer n en la pantalla para ejecutar
el programa de instalaciўn.
4. Si se le pide, seleccione «Usar modo protegido».
Aviso acerca del software antivirus
————————————
Si hay algЈn programa antivirus en ejecuciўn durante la instalaciўn,
es posible que impidan que el programa de instalaciўn actualice
correctamente los archivos del sistema.
**********
IMPORTANTE: Durante la instalaciўn, es posible que aparezca un mensaje
de advertencia, que le informa de que cambiў el registro de arranque
u otros archivos. Si aparece ese mensaje, DEBE ACEPTAR los cambios o
el programa de instalaciўn no podr actualizar los archivos importantes
que utiliza Windows Millennium Edition para iniciar el equipo.
**********
El programa de instalaciўn deja de responder durante la detecciўn de
hardware
—————————————————————————-
—
Si el programa de instalaciўn deja de responder durante la detecciўn
del hardware del equipo, apague el equipo, espere unos segundos y
enci‚ndalo de nuevo. Es posible que necesite hacerlo varias veces.
Si se le pide, seleccione «Usar modo protegido» al iniciarse el programa
de instalaciўn. El programa de instalaciўn podrЎa dejar de responder
durante varios de los mўdulos de detecciўn y omitir las reas en las que
se produzcan errores para poder finalizar correctamente.
**********
IMPORTANTE: Utilice el interruptor del equipo para apagarlo por
completo. No utilice el botўn de reinicio ni presione CTRL+ALT+SUPR
para reiniciar el equipo.
**********
Si, aЈn asЎ, el programa de instalaciўn no finaliza correctamente,
puede que sea necesario iniciar el equipo en el modo a prueba de
errores para que pueda ver los temas de Ayuda acerca de la
detecciўn de hardware.
======================================
DESINSTALAR WINDOWS MILLENNIUM EDITION
=======================================
Si los pasos anteriores no funcionan, puede probar a desinstalar
Windows Millennium Edition y volver a la versiўn anterior de Windows.
Para desinstalar Windows Millennium Edition, debiў elegir guardar
la informaciўn de desinstalaciўn durante en el programa de instalaciўn
de Windows Millennium Edition. La informaciўn de desinstalaciўn se
guarda en los archivos Winundo.dat y Winundo.ini. Si elimina estos
archivos no podr desinstalar Windows Millennium Edition.
**********
IMPORTANTE: no intente desinstalar Windows Millennium Edition si la
informaciўn de particiўn de su disco duro cambiў desde la Јltima
instalaciўn correcta de Windows Millennium Edition.
Windows Millennium Edition crea una copia de seguridad de la
informaciўn de la particiўn del disco duro en el archivo
Suhdlog.dat al terminar una informaciўn correcta, y Uninstal.exe
restaura en el disco duro la informaciўn de particiўn que encuentra
en Suhdlog.dat. Si la informaciўn de particiўn del disco duro cambiў
desde la Јltima instalaciўn correcta (en concreto, desde que se creў
Suhdlog.dat), es posible que pierda parte de los datos, o todos
ellos, al intentar desinstalar Windows Millennium Edition.
**********
Para desinstalar Windows Millennium Edition:
1. Utilice el disco de inicio de Windows Millennium Edition para
reiniciar el equipo y seleccione la opciўn 1 en el menЈ de
inicio y, a continuaciўn, haga presione ENTRAR.
2. Cierre el archivo de Ayuda.
3. En el sЎmbolo del sistema, escriba cada una de las siguientes
lЎneas y presione ENTRAR despu‚s de cada una de ellas.
smartdrv
<unidad>:
cd<windows>command
uninstal.exe
NOTA: <unidad> es la letra de la unidad en la que se encuentra
la carpeta Windows (la predeterminada es C). <windows> es el nombre
de la carpeta de Windows (el predeterminado es «Windows»).
4. Escriba S cuando se le pregunte si desea continuar.
Este proceso puede durar varios minutos.
NOTA: SmartDrive (Smartdrv.exe) no es necesario para ejecutar
Uninstal.exe, pero acelera mucho el proceso.
=================================================================
INSTALAR WINDOWS MILLENNIUM EDITION CON WINDOWS NT O WINDOWS 2000
=================================================================
No puede instalar Windows Millennium Edition sobre una versiўn de
Windows 2000 o Windows NT, pero ambas pueden coexistir en un mismo
sistema.
No obstante, por motivos de compatibilidad, se recomienda que
instale cada versiўn en un disco duro o particiўn diferente.
Si Windows NT ya est instalado, el programa de instalaciўn de
Windows Millennium Edition se agregar al menЈ de inicio de Windows NT
para permitir alternar entre el inicio de Windows Millennium Edition
y de Windows NT.
===========================================================
INSTALAR WINDOWS MILLENNIUM EDITION EN UN DISCO DURO NUEVO
===========================================================
Consulte el documento «Instalar Windows Millennium Edition en un disco
duro nuevo», que encontrar en <CD-ROM>:Win9xCleanhd.Txt.
Tambi‚n puede resultarle Јtil el archivo l‚ame del programa de instalaciўn.
Se encuentra en <CD-ROM>:Win9Xinstalar.txt.
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]
Welcome to the Great Internet Mersenne Prime Search!
In case you ever forget, the URL is http://www.mersenne.org/prime.htm.
My email address is [email protected].
For networking questions, contact Scott Kurowski at [email protected].
FILE LIST
———
readme.txt This file.
prime95.exe The program to factor and run Lucas-Lehmer tests on
Mersenne numbers.
rpcnet.dll Communicates with the Internet PrimeNet server using RPCs.
httpnet.dll Communicates with the Internet PrimeNet server using HTTP.
whatsnew.txt A list of new features in prime95.exe.
prime.ini A file containing your preferences. The menu choices
and dialog boxes are used to change your preferences.
local.ini Like prime.ini, this file contains more preferences.
The reason there are two files is discussed later.
worktodo.ini A list of exponents the program will be factoring
and/or Lucas-Lehmer testing.
results.txt Prime95.exe writes its results to this file.
prime.log A text file listing all messages that have been sent
to the PrimeNet server.
prime.spl A binary file of messages that have not yet been sent to
the PrimeNet server.
pnnnnnnn & Intermediate files produced by prime95.exe to resume
qnnnnnnn computation where it left off.
database This optional binary file is downloaded separately. You only
need this file if you are not using the PrimeNet server.
It contains all the Mersenne exponents that still need testing.
WHAT IS THIS PROGRAM?
———————
This program is used to find Mersenne Prime numbers. See
http://www.utm.edu/research/primes/mersenne.shtml for a good
description of Mersenne primes. Mersenne numbers can be proved
composite (not prime) by either finding a factor or by running
a Lucas-Lehmer primality test.
INSTRUCTIONS
————
There are two ways to use this program. The automatic way uses
a central server, which we call the PrimeNet server, to get work to do
and report your results. Anyone with Internet access, including AOL,
CompuServe, and dial-up ISP users should use this method. You do not
need a permanent connection to the Internet.
The second method is the manual method. It requires a little more work
and monitoring. I recommend this for computers with no Internet access
or with some kind of firewall problem that prevents the automatic method
from working.
If you are running this program at your place of employment, you should
first GET PERMISSION from your network administrator or boss. This is
especially true if you are installing the software on several machines.
Some companies are reluctant to run any software they are not familiar
with.
INSTRUCTIONS FOR THE AUTOMATIC METHOD
————————————-
1) Download and unzip prime95.zip. You've probably done this already
since you are reading this file.
2) Connect to the Internet.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address.
Optionally enter a user ID and password. An easy-to-remember user ID
will be helpful if you plan to visit the PrimeNet server's web page
to view reports on your progress. If you do not enter a user ID or if
you pick a user ID that is already in use, then the server will assign
a user ID.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, leave the «Use Primenet…» checkbox
checked. Do not turn this checkbox off even if you disconnect
from the Internet. Check the «Use a dial-up…» checkbox
if you use a modem to connect to the Internet. Note that prime95
will not dial-up to connect to the Internet, rather it waits
for a time when you are already connected to contact the server.
Click OK. Prime95 will now contact the PrimeNet server to get some
work for your computer to do.
4) If you cannot contact the PrimeNet server, then a firewall may be
preventing the RPCs from getting to the server. In this case, you
may want to try the HTTP-based DLL. Choose «Use HTTP-based DLL»
from the Test/Primenet dialog.
4a) If you now get the error message «Unable to load HTTPNET.DLL», then
you are probably missing WININET.DLL. This DLL is shipped with
Microsoft's Internet Explorer. It is also installed by default in
later versions of Windows 95 and Windows NT. You can download and
install WININET.DLL from Scott Kurowski's web site. See
http://entropia.com/ips/faq.html#wininet for details.
4b) If the http-based DLL will not connect to the server, then
you will have to use the manual method described below. There have
been reports that the http-based DLL does not work in all
MS IE 3.0 environments — we are working on making this DLL work in
as many different environments as possible.
4c) If a proxy server is the cause of your connection troubles, see the
later section on «SETTING UP A PROXY SERVER».
5) Create a shortcut to prime95.exe and place it in the startup folder.
Alternatively, you can install prime95.exe as a Windows 95 service
using the Options menu. Prime95 will now run every time you boot
your computer.
MANUAL METHOD INSTRUCTIONS #1
——————————
1) Use the Web (http://entropia.com/ips/manualtests.html) to create
a userid for yourself and to get a set of exponents to work on.
Copy these exponents to a file called worktodo.ini
2) Run prime95.exe. You will see 3 dialog boxes:
2a) In the first dialog box, enter your name and email address. Click OK.
2b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
2c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
3) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
4) Once a month or when done with your exponents, use the web pages
again to send the file «results.txt» to the PrimeNet server.
It is important to do this so the exponents you are testing are
not reassigned to someone else.
MANUAL METHOD INSTRUCTIONS #2
——————————
1) Download and unzip database.zip (http://www.mersenne.org/range2.htm).
2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of
exponents to test. Send me e-mail on the range you've chosen.
This prevents others from testing the same range.
3) Run prime95.exe. You will see 3 dialog boxes:
3a) In the first dialog box, enter your name and email address. Click OK.
3b) In the second dialog box, change the CPU type and speed if necessary.
Fill in roughly how many hours a day you leave your computer running.
Click OK.
3c) In the third dialog box, uncheck «Use PrimeNet to get work and report
results», click OK.
4) Choose Test/Manual Operation from the menus. Enter the type of work
and range of exponents you selected in step 2.
5) Create a shortcut to prime95.exe and place it in the startup folder.
Prime95 will now run every time you boot your computer.
6) Once a month or when done with your range, send the file «results.txt»
to
[email protected]. It is important to do this so the exponents
you've tested can be removed from the master list.
NOTES
——
Let prime95.exe run at all times. It runs at the lowest possible priority,
making use of all your idle CPU cycles. It should not interfere with your
normal work. Let the program run overnight and on weekends. Never turn
your computer off. Turn off your monitor to conserve energy. NOTE:
Running your computer non-stop could increase your electric bill by $30
per year or more.
It can take many CPU days to test a large Mersenne number. This program
can be safely interrupted by using the ESC key to write intermediate
results
to disk. This program also saves intermediate results to disk every 30
minutes
in case there is a power failure.
To fully utilize a dual Pentium machine, you must run two copies of
prime95.exe. Run one copy of prime95 as described above. Run the second
copy of prime95.exe with the -A1 switch. Place two shortcuts in the
startup folder (one with no switch and one with the -A1 switch).
Dual processor machines can also improve performance by setting
processor affinity in Windows NT. To do this, do the following:
1) Run Windows NT task manager
2) Click on the processes tab
3) Find your PRIME95 processes
4) Right click on the processes and pick Processor Affinity.
5) Set the flag on CPU 0 for one process and CPU 1 for the other
You can compare your computer's speed with other users by checking the
site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are
much slower than comparable machines, download Microsoft's WinTop
kernel toy to find programs (such as AOL) that are stealing all of
prime95's CPU cycles. You can download the software free at
http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher
You can get a report of your PrimeNet server account status on the web
(http://entropia.com/primenet/status.shtml). Type your UserID and
password into the web form, and click «Get Account Report». You can
get your UserID and password from the Test/User Information
dialog box.
Information about running a local PrimeNet server is also available.
See http://entropia.com/primenet. If you have any questions about the
PrimeNet server, you can send e-mail to [email protected].
The first time you run this program it will perform an hour long
self-test to make sure the Lucas-Lehmer code is running properly
on your system. There are 16 different self-tests, one for each
FFT size. You can run all 16 self-tests with Options/Self Test
menu choice. This is not required.
If you have overclocked your machine, I highly recommend running the
torture test for a couple of days. The longer you run the torture test
the greater the chance that you will uncover an error caused by
overheating.
Depending on the exponent being tested, the program may decide that it
would be wise to invest some time checking for small factors before
running a Lucas-Lehmer test. Furthermore, the program may start factoring
exponents before a previous Lucas-Lehmer test completes. This is normal!
The program will resume the Lucas-Lehmer test when the factoring
completes.
For manual users, once you've started testing a range there is no advantage
in downloading a new database. After your range completes, you can
download
a new database before you start your next range.
You can configure this program to have different properties at different
times of the day and/or to not run during certain times of the day.
Unfortunately, you must manual edit the prime.ini file. Let's say you
want to install the program on a friend's machine and he runs a screen
saver at night. He also runs a disk defragmenter at midnight on weekdays.
This prime.ini file will run the program at a higher priority than his
screen saver at night and on weekends. It also sleeps for an hour when
his defragmenter starts running. Finally, at night fewer save files are
generated to allow his disk to stay powered down longer.
UserID=foo
Time=1-5/8:30-17:30
Priority=1
DiskWriteTime=30
Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00
Priority=5
DiskWriteTime=240
The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The
time portion refers to the hours of the day based on a 24-hour clock.
You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00
is the same as Time=0:00-8:00). Unpredictable results will occur if
there are overlapping time intervals. Also note that any options that
appear in the Time= sections should not appear earlier in the prime.ini
file and you can no longer edit these options from theuser interface.
SETTING UP A PROXY SERVER
————————-
Create a file in the same local folder as Prime95.exe, called
«primenet.ini».
Add these text lines, substituting the appropriate proxy server URL and
port:
[PrimeNet Proxy]
ProxyHost=http://proxy.megacorp.com:8080
If the proxy is secured by a userid/password, add the following two text
lines, substituting the appropriate values:
ProxyUser=whatever_the_userid_is
ProxyPass=whatever_the_password_is
After the first time PrimeNet is contacted through a secure proxy, the
proxy
password is encoded and a new parameter 'ProxyMask=1' set. To change the
password, simply change the ProxyPass= value, and either delete the
ProxyMask
text line or set ProxyMask=0.
PROGRAM OUTPUT
—————
On screen you will see:
Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121
sec.
This means prime95 is in the third pass of a 16 pass process to
find a small factor of 2^400037-1.
Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec.
This means prime95 just finished the 941400th iteration of a
Lucas-Lehmer primality test. The program must execute 1667747
iterations to complete the primality test. The average iteration
took 21889762 «clock cycles» or 0.109 seconds.
The results file and screen will include lines that look like:
M2645701 has a factor: 13412891051374103
This means to 2^2645701-1 is not prime. It is divisible
by 13412891051374103.
M2123027 no factor to 2^57, WS1: 14780E25
This means 2^2123027-1 has no factors less than 2^57. The Mersenne
number may or may not be prime. A Lucas-Lehmer test is needed
to determine the primality of the Mersenne number. WS1 is
the program version number. 14780E25 is a checksum to guard
against email transmission errors.
M1992031 is not prime. Res64: 6549369F4962ADE0. WT1:
B253EF24,1414032,00000000
This means 2^1992031-1 is not prime — a Lucas-Lehmer test says so.
The last 64 bits of the last number in the Lucas-Lehmer sequence
is 6549369F4962ADE0. At some future date, another person will verify
this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the
program version number. B253EF24 is a checksum to guard against
email
transmission errors. 1414032 can be ignored it is used as part
of the double-checking process. The final 00000000 value is a set
of 4 counters. These count the number of errors that occurred during
the Lucas-Lehmer test.
M11213 is prime! WS1: 579A579A
This means 2^11213-1 is a Mersenne prime! WS1 is the program
version number. 579A579A is a checksum to guard against email
transmission errors.
RUNNING PRIME95 ON SEVERAL COMPUTERS
————————————
The easiest way to do this is to first set up prime95 on one computer.
Next copy all the files to the second computer. Delete the local.ini
file and worktodo.ini files. These files contain information that
is specific to the first computer. Start prime95 on the second
computer and optionally use Test/User Information to
give the second computer a unique computer ID. Repeat this process
for all the computers you wish to run prime95 on.
If you do not follow the instruction above, be sure you use
Test/User Information to give each computer the same
userid and password. Failure to do this will result in all
your work being «credited» to different user IDs.
TEST MENU
———
The PrimeNet menu choice lets you configure the type of work you get
from the server. The «Use PrimeNet…» option can be turned on to
switch from the manual method to the automatic method.
The «Request whatever…» box should be left checked. However, if you
are running a slow computer and don't mind waiting several months for
a single Lucas-Lehmer test to complete OR you are running a faster
computer and would rather do factoring, then uncheck this box and
choose a different type of work to do. The «Days of work to get» should
be changed based on how often you connect to the Internet. As long as
you connect at least once in the given time period, prime95 will have
an uninterrupted stream of work. However, the program will not checkout
more than 20 exponents no matter what «Days of work to get» is set at.
The Manual Operation menu choice allows you to select a range of
exponents to work on. You may also use this menu choice to add
to your existing work (e.g. when you are running low on exponents
to test).
The User Information menu choice lets you change your name and email
address. Your name will be used in credits and «top producers»
web pages. Your email address will be used to send you warnings if
an exponent you have reserved is about to expire and to send you a
newsletter once every few months. Select the no email checkbox to
stop the server from sending expiration warnings. The userid you
use will appear in the status pages on the PrimeNet server. You can
also set the ComputerID field if you have several computers and want
to keep track of which computers produced which results.
The Vacation/Holiday menu choice lets prime95 update the expected
completion
dates on the PrimeNet server. This will prevent one of your exponents
from being reassigned while you're gone. Also, if you are taking a
long vacation, prime95 will get extra exponents to test. For example,
if you are leaving immediately for a 6 week vacation, connect to the
Internet and choose 42 days. If you are leaving in two days for a 6
week vacation, then set choose 44 days. Primenet will send the new
completion dates whenever you connect to the Internet over the next 2 days.
The Status menu choice will tell you what exponents you are working on.
It will also estimate how long that will take and
your chances of finding a new Mersenne prime.
The Continue menu choice lets you resume prime95 after you have stopped it.
The Stop menu choice lets you stop the program. When you continue,
you will pick up right where you left off. This is the same as hitting
the ESC key.
ADVANCED MENU
————-
You should not need to use the Advanced menu. This menu choice is
provided only for those who are curious to play with. To avoid confusion
for novice users, all the choices in the Advanced menu have been grayed.
Please read this section if you want to know what the Advanced menu choices
do. To turn on the Advanced menu, use the Advanced Password dialog box
and enter a value of 9876. Also note that many of the menu choices are
grayed while testing is in progress. Choose Test/Stop to activate
these menu choices.
The Test choice can be used to run a Lucas-Lehmer test on one Mersenne
number. Enter the Mersenne number's exponent — this must be a prime
number between 7 and 5259999.
The Time choice can be used to see how long each iteration of a Lucas-
Lehmer
test will take on your computer and how long it will take to test a
given exponent. For example, if you want to know how long a Lucas-Lehmer
test will take to test the exponent 876543, choose Advanced/Time and
enter 876543 for 100 iterations. A Pentium will automatically time
and compute the results. 486 owners will need to time how long the
operation
takes by hand, divide that time by 100 and multiply by 876543 to compute
how
long a full Lucas-Lehmer test will take.
The ECM choice lets you factor small Mersenne exponents using the
Elliptic Curve Method of factoring. Select a few exponents and bounds
to factor from the http://www.mersenne.org/ecm.htm web page.
Note: You do not reserve exponents to work on, several people can
do ECM factoring on the same exponent. The program uses a random
number generator to select elliptic curves to test. You must email
results to me at [email protected] — primenet does not support ECM
factoring. You can also edit the worktodo.ini file directly. For example:
ECM=751,3000000,0,100,0,0,0
The first value is the exponent. The second value is bound #1. The
third value is bound #2 — leave it as zero. The fourth value is the
number of curves to test. The fifth value is the number of curves
completed.
The sixth value is the specific curve to test — it is only used in
debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1
factoring.
The Clear Primes choice can be used to remove one or more exponents from
the
database. You might do this for two reasons:
1) Let's say you're testing range 1234000 to 1234999. If I send you some
mail saying that a factor has been found for M1234567, then you use
Clear Primes to remove 1234567 from your database so that you
won't have to run a Lucas-Lehmer test on it.
2) You downloaded a new database after checking all the exponents
between 1234000 and 1234300. You can use Clear Primes
to remove the exponents between 1234000 and 1234300.
Do not use the Factor menu choice. If you're running Lucas-Lehmer tests
on a range or just factoring a range — use Test/Manual Operation.
The program will know the optimal amount of factoring to perform. Having
said that, if you insist on using this menu choice, you can look for
factors
less than 2^62 of any Mersenne numbers with an exponent less than
10,000,000.
Let's say you're writing a factoring program for a UNIX machine and want to
check its results. Use both this menu choice and your UNIX program to
search for small factors on a set of Mersenne numbers and compare the
results.
Round off checking. This option will slow the program down by about 15%.
This option displays the smallest and largest «convolution error». The
convolution error must be less than 0.49 or the results will be incorrect.
There really is no good reason to turn this option on.
The Priority menu is used to adjust the priority prime95 runs at.
You should not need to change this. You might raise the priority
if you (or your coworker) just cannot live without your screen
saver (bad idea), or if you are running some ill-behaved program
that is using CPU cycles for no good reason.
The Manual Communication menu choice should only be used if the
automatic detection of an Internet connection is not working for you.
Using this option means you have to remember to communicate with the
server every week or two (by using this same menu choice).
The Quit GIMPS menu choice is used when you no longer want this computer
to work on the GIMPS project. You may rejoin at a later date.
If you are a PrimeNet user your unfinshed work will be returned to the
server. If you are a manual user, you need to send me email containing
your results.txt file and a note saying you are quitting.
OPTIONS MENU
————
The CPU menu choice lets you tell the program what kind of CPU you
have. The program will normally figure this information out for you.
This information is used to give accurate time estimates in the
Test/Status menu choice. It is also used, to choose between integer
based factoring (Cyrix and 486) and floating point based factoring
(Pentium and Pentium Pro). No matter what you choose, the program
uses the same code to run the Lucas-Lehmer primality test. If you have
an AMD K5 or Cyrix M2 chip, choose Cyrix 6×86.
The Preferences menu choice lets you control how often a line is
written to the main window. Also how often a line is written to
the results file. It also lets you change how often
intermediate files (to guard against power failure an crashes)
are created. You can control how often the program checks to
see if you are connected to the Internet. The program polls
whenever it has new data to send to or work to get from the PrimeNet
server. If you are low on disk space, you can select one intermediate
file instead of two. However, if you crash in the middle of writing
the one intermediate file, you may have to restart an exponent from
scratch. You can also tell the program to be quiet, rather than
beeping like crazy, if a new Mersenne prime is found.
The Self Test choice lets you run a sixteen-hour self test. Passing the
self-test does not guarantee that you will not run into any hardware
problems later on, but it does give you some confidence that the program
is working properly.
The Torture Test choice will run a continuous self test. This is great
for testing machines for hardware problems.
The Tray Icon choice will cause prime95 to have a small icon on the taskbar
when it is minimized. You can activate the program by double-clicking on
the small icon. If you place the cursor over the small icon, a tooltip
will
display the current status.
The No Icon choice is only enabled if the Advanced Menu is activated
with the password. Using this menu choice means there will be no
prime95 icon on the taskbar once you minimize the program (making it very
hard to reactivate!) If you turn this feature on and want to turn it
back off, edit prime.ini and change the line «HideIcon=1» to «HideIcon=0»,
then reboot.
Checking the Windows 95 Service menu choice will install prime95
as a service. The program will be run automatically whenever
you reboot your machine. You will not need to place a shortcut to
prime95 in the startup menu.
COMMAND LINE ARGUMENTS
———————-
These command line arguments can be used to schedule prime95.exe to
run only at certain times of the day or at a different priority. Note
that raising the program's priority will not make it run any faster
on an idle machine.
-Tdd:hh:mm This tells the program to terminate itself after
the specified number of days, hours, and minutes.
The days and hours are optional. For example,
use Windows 95 Plus Pack's scheduler to run the
program on your co-worker's machine for 12 hours
every evening with the -T12:00 argument.
-An This is used to run two or more copies of prime95
from the same directory. Using this switch causes prime95
to use a different set of filenames for the INI files,
the results file, the log file, and the spool file.
Just use a different value of n for each copy of
prime95.exe you start.
-Wdirectory This tells prime95 to find all its files in a different
directory than the executable.
POSSIBLE HARDWARE FAILURE
————————-
If the message, «Possible hardware failure, consult the readme file.»,
appears in the results file, then prime95's error-checking has
detected a problem. Prime95 will continue from the last save file.
If you do not get the message, «Disregard last error…», then the
problem is not reproducible — a definite sign of hardware problems.
How can this be when none of your other programs have problems? The answer
is that prime95 stresses your machine more than any other program you
run. The operating system usually shuts down the floating-point unit
when no programs are using it. Prime95 continuously uses the FPU,
consuming
more electricity and generating more heat. If the CPU is not properly
cooled,
errors can occur. Prime95 also constantly accesses main memory — up to
60MB per second. This constant activity will detect memory problems that
other programs do not. This is why Cray Research has used a program
similar
to this one as part of its supercomputer diagnostics package for over a
decade.
Could it be a software problem? If the error is ILLEGAL SUMOUT, then
there is a good chance that this is a software problem. A device driver
or VxD may not be saving and restoring CPU state correctly. The good news
is that prime95 recovers very well from ILLEGAL SUMOUT errors.
Try seeing if the problem occurs only when a specific device is active
or a specific program is running.
How can you track down the hardware problem? Unfortunately, this is not
easy. To see if your CPU is overheating, run prime95 for several hours.
Open the box. Is the CPU too hot to touch? If so, a heat sink or
CPU fan should solve the problem. Memory problems are not as easy to
diagnose. My only advice is to try swapping memory SIMMs with a coworker's
or friend's machine. If the errors go away, then you can be confidant
that the original problems were memory related.
What can you do if you are unwilling or unable to find the hardware
problem?
If you are only getting an error once in a while, then your results are
probably OK. The error-checking code is not infallible, so your results
will need to be double-checked. If you are getting several errors during
each primality test, then I would recommend using your machine to factor
Mersenne numbers.
LUCAS-LEHMER DETAILS
———————
This program uses the Lucas-Lehmer primality test to see if 2**p-1 is
prime.
The Lucas sequence is defined as:
L[1] = 4
L[n+1] = (L[n]**2 — 2) mod (2**p — 1)
2**p-1 is prime if and only if L[p-1] = 0.
This program uses a discrete weighted transform (see Mathematics of
Computation, January 1994) to square numbers in the Lucas-Lehmer sequence.
DISCLAIMER
———-
THIS PROGRAM AND INFORMATION IS PROVIDED «AS IS» WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE.
THANKS
——
Happy hunting and thanks for joining the search,
George Woltman
[email protected]