Multiple Installations.

[A_Pryme]

Can anyone give me some info on creating a new directory for Prime95 for the purposes of running two instances of the program simultaneously on the same machine?

[Peter Nelson]

It is certainly possible to have more than one instance running, working off different working directories.

You would only benefit from doing this simultaneously if you have either a multiprocessing (eg dual P3) or a hyperthreading cpu like P4 running in hyperthreading on mode in the bios.

In addition you should set the affinity of each instance to the cpu or thread you want it to use (0 or 1).

Instructions on overriding the default working directory are located in the undoc.txt file.

[Mystwalker]

There is no need for a new directory for a second instance. All you have to do is: call prime95 with e.g. the parameter "-Ax" (or was it "Ax" only?), which uses other filenames (they get labeled with the "x").
I'm not sure how they are named in detail, you'll see once you try it.

[A_Pryme]

Originally Posted by Peter Nelson

You would only benefit from doing this simultaneously if you have either a multiprocessing (eg dual P3) or a hyperthreading cpu like P4 running in hyperthreading on mode in the bios.

That puter I am using for this is a

Intel Celeron processor 631.4 MHz
RDTSC, CMOV, PREFETCH, MMX, SSE
Cache, L1: 16Kb, L2: 128Kb.

I think I read an article about WinMe and hyperthreading about a year ago but don't remember the exact content.

[A_Pryme]

Originally Posted by Mystwalker

There is no need for a new directory for a second instance. All you have to do is: call prime95 with e.g. the parameter "-Ax" (or was it "Ax" only?), which uses other filenames (they get labeled with the "x").
I'm not sure how they are named in detail, you'll see once you try it.

Is that similar to renameing batch files? The same file name on all of them except for an added system parameter that doesn't effect the "real" file name?

[A_Pryme]

Originally Posted by Peter Nelson

You would only benefit from doing this simultaneously if you have either a multiprocessing (eg dual P3) or a hyperthreading cpu like P4 running in hyperthreading on mode in the bios.

This is the machine I'm doing this with:

System Model Emachines
System Type X86-based PC
Processor Intel Celeron processor GenuineIntel ~633 Mhz
BIOS Version EPP revision 9.00

Total Physical Memory 30.45 MB
Available Physical Memory 160.00 KB

Total Virtual Memory 2.00 GB
Available Virtual Memory 1.91 GB
Page File Space 1.97 GB

I was looking for info on hyperthreading and running multiple instances of Prime95 but have found little.

You got a link on that info?

[Uncwilly]

On a machine with any single non-HyperThreading processor, Prime95 will have the best total speed with only a single instance running. It is so very efficent that the swaping out of programs that Windows does would make it less efficent.

With that little amount of RAM on that machine, you would likely be best doing only trial factoring.

[Digital Concepts]

Your machine does not appear to be a dual processor, nor HT capable.

But if you still want to run multiple prime95 copies, from the readme.txt file...

COMMAND LINE ARGUMENTS
----------------------

-An This is used to run two or more copies of prime95
from the same directory. Using this command line argument
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.

P.S. I agree with Uncwilly

[A_Pryme]

Originally Posted by Uncwilly

With that little amount of RAM on that machine, you would likely be best doing only trial factoring.

The current worktodo is listed as being done approx March 20. I will let that conclude.

Does the trial factoring machines come into the reward anywhere for finding a new prime?

[lycorn]

Originally Posted by A_Pryme

Does the trial factoring machines come into the reward anywhere for finding a new prime?

Trial Factoring machines are not actually searching for new primes, they are eliminating potential candidates by finding factors. Therefore, there is no "reward" in the true sense of the meaning. But mind you, it is a very important contribution to the project, for any time you eliminate a candidate you save two Lucas-Lehmer tests (First-Time and Double Check), and those are the really lenghty pieces of work.
Now trial factoring has been traditionally allocated to slower machines, and particularly the ones that are not SSE2 capable, as in the latest versions of Prime95 the implementation of the FFT algorithm (used in the LL tests but not in the TF code) has been strongly SSE2 optimized. That´s why people in the forum have suggested that you perform Trial Factoring.
But in the end, it is your machine, do whatever type of work you enjoy the most. Keep in mind that in a volunteer project like this every single bit of contribution is welcome.
Welcome aboard!...

[A_Pryme]

lycorn,

With either task it will be running 24/7 so might as well look for a prime.

Will this run on Win 3.11/DOS 6 ?