Volunteer computing & the hunt for prime numbers

Author: Iain Bethune
Posted: 29 Sep 2014 | 15:52

As well as helping out with our drop-in workshop at the British Science Festival in early September, I also had the chance to give a talk as part of the Festival's public lecture programme. Over 75 people turned out early on Sunday morning to hear 'Seventeen or Bust: Solving hard mathematical problems with your help!', where I explained how the PrimeGrid project is working on a solution to Sierpinski's conjecture, a fifty-year-old unsolved problem in Number Theory, as well as finding record-sized prime numbers in the process.

PrimeGrid works thanks to tens of thousands of volunteers worldwide who contribute computer time by downloading the BOINC software and connecting their home computers to PrimeGrid. BOINC (the Berkeley Open Infrastructure for Network Computing) is now used by hundreds of similar projects, and PrimeGrid is one of the largest. Once connected, volunteers' computers download small work units, ranging from a few hours to a few days, which are computed in the background, or when their computers are idle.

Cray T94 Supercomputer

The combined power of all of these computers can be measured in PetaFLOPs and it rivals some of the world's largest supercomputers - in fact, the last record prime to have been found on a supercomputer was back in 1996 on the Cray T94. Since then the record has been extended 12 times, all by volunteer computing.

If you want to watch the whole talk, you can find it on YouTube, or watch below. And if that inspires you to join in the search for yourself, follow the simple instructions at www.primegrid.com to get started searching for your own mega-primes!

Image shows a Cray T94, the last supercomputer to hold the record for the largest known prime number in 1996.


Iain Bethune, EPCC