PRIMEOS2 and PRIMEEMX homepage


This is the OS/2 version of the Mersenne prime program by George Woltman. With it you can participate in the Great Internet Mersenne Prime Search which is your chance to gain immortality as dicoverer of a new prime number. See for more information the PRIMEOS2 readme file. The main improvement over version 2 is the inclusion of the PRIMENET functionality, the larger FFT's and 64 bit factoring code.


The EMX version of the mersenne prime program is the same as the OS/2 version just compiled and linked in another way so it can work with de EMX 32 bit DOS extender. It is a bit slower than PRIMEOS2, so OS/2 users should still use PRIMEOS2. See for more information PRIMEEMX readme file. Actually you can use this on all DOS and Windows platforms but for the most there is not much to gain. For Windows 95 and NT there is a much better alternative, Windows 3.1 users might want to use it to be able to test the large exponents. Also there is no PRIMENET functionality available.

Latest version

Since 3 april 1999 version 3.3.1 is available which is a port of the 18.1.2 version of George's program for Linux (mprime). It is still a beta version. See its README and WHATSNEW files for more information

More info

If you have questions about DOS or OS/2 specific features of the program you can reach me an email.

Download the latest version

Download the latest version (3.3.1) of PRIMEOS2 or PRIMEEMX. When using PRIMEEMX you also need the runtime of the 32 bit DOS extender (version 0.9c or up) or the RSX DPMI DOS extender.


Since 12 aug 1997 this page has been requested 6356 times.
PRIMEOS2.ZIP has been downloaded 1490 and PRIMEEMX.ZIP 714 times.
This page has last been updated on 3 april 1999