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 6x86.
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
woltman@magicnet.net
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 woltman@magicnet.net.
For networking questions, contact Scott Kurowski at primenet@entropia.com.
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
woltman@magicnet.net. 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