Glorying in the prime of his life

By MALCOLM BURGESS

Everyone knows that recycling can make a big difference to the environment. But what about your computer? It seems a tragedy that the only thing which comes close to fully using its awesome power is a blood-and-guts game.

Auckland web designer Leon Matthews decided to set aside some of his machine's unused resources for a higher calling.

A high one indeed - in fact, so high that the number describing it is more than 20km long when written down.

About four years ago, Matthews installed a free program that would quietly set about the task of hunting down astronomically large prime numbers, while he went about his day-to-day job as technical director of Auckland web-design firm Messiah.

Just recently, Matthews and hundreds of thousands of other computer-users who had done the same hit paydirt. It appeared on a volunteer's machine in Michigan.

The number, known as a Mersenne prime, is only the 40th of its kind to be found since Euclid predicted its existence in 350AD.

The new one - 2 to the power of 20,996,011 minus 1 - takes 6.4 million decimal digits to write out in full.

But why hunt down a prime, which can only be divided by one and itself.

Their practical uses range from cracking codes to finding stars.

They are also important in software for large institutions such as banks who are keen on preserving tight security and privacy.

The largest primes such as the Mersennes are not so easy to apply to ordinary life, but they are important for random-number generators used in everything from astrophysics to protecting networks against hackers.

All the credit for "finding" the latest number may have gone to American Michael Schafer, on whose computer it was found, but Matthews and others like him are just as much a part of the discovery.

The number was found using an ordinary desktop PC that was part of a global co-operative of 211,000 such machines using the same software and loosely connected via the internet - one of the most powerful clusters in the world, equivalent to 343 Cray T916 supercomputers.

The Great Internet Mersenne Prime Search - lovingly referred to as Gimps - spent a staggering 25,000 years of computer time to find the prime.

"If anyone should take the credit, it's George Woltman, who created the software," says Matthews.

"Schafer would just have had to click 'download', and double-click."

Fame and riches may spur many more people like him on. A $100,000 award has been offered for the discovery of a 10-million-digit prime, to encourage Gimps participants to crack on with the next target.

Since Matthews became involved in the project he has contributed 522 "CPU (central processing unit) years" to the search for Mersenne Primes - not bad for a 27-year old from Mt Eden.

Out of the hundreds of thousands of volunteers involved, his contribution weighs in at number 75 - down from a high of 49, he notes.

Further up the scale are the big universities and institutions, which have more resources to donate.

"I couldn't stand the idea of CPU cycles going to waste," says Matthews, an evangelist for information efficiency who installs the program on every computer he can.

If prime numbers seem too much like pure maths, there are plenty of other "distributed computing" projects that practically anyone can join.

These range from the difficult task of folding proteins to look for new drugs against diseases such as cancer and Aids, to searching for life on other planets.

What they all have in common is the concept of using the downtime of PCs throughout the world, all hooked up via the internet.

From his desk in Mt Eden, Matthews donates more than just his processing power.

He is part of Project Gutenberg, the network of people who upload copyright works to the internet to create a super-library of the world's literature.

This month is a milestone for the project, which uploaded its 10,000th volume of literature - the Magna Carta.

Besides proofreading a couple of pages of uploaded text a day, Matthews has written software to help compress parts of the project, so that people can access them more easily.

But it does not stop there. Plain text is notoriously tough on the eye and tricky to turn into HTML code - the way you normally read words on a web browser.

To remedy this, Matthews is writing software that will make the free texts easier to read. And he plans to give that away, too.

"It's better than keeping it on my server and bogging it down."

So what drives someone who has to make a buck from his IT endeavours to spend so much energy on the free flow of information? How does he square this interest with the commercial imperative of his business?

Matthews says he is still thinking about that one, but the factors uniting the Mersenne prime search and Project Gutenberg are those of free information and a hatred of waste.

Oh, he says, and the fact that small efforts of small guys can lead to big things.

Many PCs, light work

Q. What is distributed computing?

A. Also known as grid computing, it involves dividing a large problem into smaller manageable parts, before farming them out for a large number of computers to solve. The solution to each is then combined with the rest to come up with an answer for the whole.

Q. Can anyone contribute?

A. Usually, as long as you have access to a PC of sufficient power (eg, a Pentium class computer) and a dial-up internet connection. Some projects involving particularly sensitive data aren't open to the general public, but the majority are.

Q. What does it cost me?

A. GIMPS, for example, sends only a few hundred bytes every week or so, hardly impacting on the performance of a network and operating at the computer's lowest priority. It doesn't need a continuous web connection, but you need to leave your machine on for most of the time.

Distributed Computing Projects