Fairly decent and accurate coverage on news.com (CNet) at the following link.

Apologies for the HTML that is embedded in the text pasted in below.   If 
your mail software can't read the HTML, follow the link to the original site.

http://news.cnet.com/news/0-1003-200-8159590.html?tag=tp_pr

Distributed computing strikes gold

By Stephen Shankland

Staff Writer, CNET News.com
December 13, 2001, 4:00 a.m. PT

A 20-year-old in Owen Sound, Canada, has found the world's largest known 
prime number using a mere desktop computer. But he didn't work alone: His 
system was part of a 210,000-machine quasi-supercomputer stretched across 
the globe.

Using a computer with an 800MHz chip from Advanced Micro Devices, Michael 
Cameron found the prime number on Nov. 14, according to Entropia. The San 
Diego company sells software to enable "distributed computing," which 
harnesses the unused processing abilities of computers scattered across the 
Internet.

Although the arrival of profit motive has transformed distributed 
computing, its roots remain in academic pursuits such finding optimal 
Golomb rulers or alien radio signals.

Cameron's computer found the number, but he shares credit with others: 
George Woltman, who founded the Great Internet Mersenne Prime Search 
(GIMPS) and wrote the search software, and Entropia founder Scott Korowski, 
who created the network system called PrimeNet that governs the 210,000 
computers that are part of the effort.

Prime numbers, once a mathematical curiosity but now crucial to encrypted 
communications, are numbers greater than one that are divisible only by one 
and the number itself. Cameron was participating in a project to search for 
a particular type of prime number called a Mersenne prime.

The number that Cameron discovered--2 to the 13,466,917th power minus 
1--has 4,053,946 digits. In order to cram his discovery onto a 
29-inch-by-40-inch poster sold by Perfectly Scientific, the number is 
printed in a tiny 1.37-point font and read with a magnifying glass.

Mersenne primes are named after Marin Mersenne, a French monk born in 1588 
who investigated a particular type of prime number: 2 to the power of "p" 
minus one, in which "p" is an ordinary prime number.

Mersenne primes are much rarer than ordinary primes. The GIMPS effort, 
exhaustively searching for possible candidates since 1996, has been 
responsible for discovering the five most recent examples. Altogether, 39 
have been discovered so far.

Cameron's computer took 42 days to verify that the number was a Mersenne 
prime. After that, researchers using a workstation took three weeks to 
confirm the work.

Prime numbers are needed for encrypted communications such as a Web 
browser's Secure Sockets Layer (SSL) technology that makes it harder to 
sniff out credit card numbers or other private information. But those 
systems typically use primes that are merely 300 or so digits, said 
Stanford University mathematician Dan Boneh.

"The large Mersenne primes are not very useful," Boneh said, though finding 
one will grant a person 15 minutes of fame.

Mathematical hobbyists have provided online versions of Cameron's number 
written out in decimal form or in words.

Searching for Mersenne primes is computationally intense, but it is a 
problem that's known as "embarrassingly parallel," which means it can 
easily be broken down into independent parts that separate computers 
tackle. Many supercomputer problems take another form, requiring high-speed 
communication between separate computers or requiring that a problem be 
solved one step at a time with little opportunity for sharing among many 
systems.

Parallel computing tasks aren't merely academic. Sun Microsystems and Intel 
use distributed computing software to help design microprocessors, and 
companies such as Entropia, Turbolinux, Platform Computing, Parabon 
Computation and United Devices have software that can be used for work in 
genetics, pharmaceuticals or financial services. Typically, this software 
is used within a single corporation rather than on strangers' computers 
across the Internet.

The concept of distributed computing is closely related to "grid" 
computing, which unites computers and storage systems into a single pool of 
resources. The National Science Foundation is among those interested in the 
concept, devoting $53 million to one grid.

Entropia, IBM, Sun, Platform Computing and others are working with the 
open-source Globus Project to define standards and software for controlling 
grids.

Ultimately, researchers envision a future in which all computers are linked 
into a single mammoth resource that can be tapped when needed.

The Mersenne prime search is moving in that direction. Each day, its 
network of computers does work that would take a single 90MHz Pentium 
computer 200 years to accomplish. On average, the network of computers 
performs 2.4 trillion calculations per second.

The most popular model in the prime number hunt is a computer with an Intel 
Pentium III chip, with AMD Athlon chips coming in a close second.

Although the search effort is voluntary, there is an incentive to 
participate. The Electronic Frontier Foundation paid $50,000 to GIMPS 
participant Nayan Hajratwala of Plymouth, Mich., upon discovery of the 
first prime number with more than a million digits. Funded by an 
individual's specific donation, the organization also is offering $100,000 
for the first 10 million digit prime, $150,000 for the first 100 million 
digit prime, and $250,000 for the first 1 billion digit prime.

Searchers are now looking for the 40th Mersenne prime. Software for the 
task can be downloaded from the Mersenne Web site.


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