Almost two years after the release of Windows Vista, it is Windows XP that gets to play a role in the discovery of the largest prime number yet. At no less than 12,978,189 digits, the UCLA Mersenne Prime number is 2^43112609 - 1, and has been “christened” M46.

Mersenne Prime researcher Landon Curt Noll has made the actual number available online. The approximately 13 million digits weight in at no less than 7.13 MB. M46 qualifies the UCLA mathematicians for a prize of no less than $100,000 from the Electronic Frontier Foundation for the discovery of the first prime number with in excess of 10 million digits.

“The UCLA Mersenne Prime was reported on August 23, 2008 on a computer named zeppelin.pic.ucla.edu, a Dell Optiplex 745 running Windows XP with an Intel Core 2 Duo E6600 CPU running at 2.4 GHz. The name ‘zeppelin’ was part of our Classic Rock Band series of computers,” revealed a UCLA System Administrator, Edson Smith.

Despite Smith's reference to a single computer, UCLA actually used no less than 75 machines connected over a network, all of them running Windows Vista's precursor. “Glad they weren’t using OS X or Linux. I’m a PC. I rock Zeppelin,” stated Keith Combs, Microsoft Technical Evangelist. The first prime number with over 10 million digits was tested and confirmed via a 75-year old algorithm dubbed the Lucas-Lehmer Test.

“We realized that our large (75 seat) PIC/Math Computer Lab was using only a fraction of its available CPU power. Rather than let all those cycles go to waste, we looked at a number of distributed computing projects, determining that GIMPS was the best fit for us. In addition to the appropriateness of GIMPS being a Mathematics-based project, we found that it was very well-written and didn't interfere with the undergraduate computer users (this was not true of some of the other project software we investigated),” Smith added.