[Paleopsych] Low-Cost Supercomputer Made With 1,100 PC's

[Steve]

http://www.nytimes.com/2003/10/22/technology/22SUPE.html?ex=1095652800&e  
n=d518ee6a0c2b9d8f&ei=5070

By JOHN MARKOFF

Published: October 22, 2003



Virginia Tech
At Virginia Tech, technicians and students have built a supercomputer, 
above, using 1,100 Apple Macintosh computers. Srinidhi Varadarajan, below, 
director of the school's computing operation, works on a program.


SAN FRANCISCO, Oct. 21 - A home-brew supercomputer, assembled from 
off-the-shelf personal computers in just one month at a cost of slightly 
more than $5 million, is about to be ranked as one of the fastest machines 
in the world.

Word of the low-cost supercomputer, put together by faculty, technicians 
and students at Virginia Polytechnic Institute, is shaking up the esoteric 
world of high performance computing, where the fastest machines have 
traditionally cost from $100 million to $250 million and taken several 
years to build.

The Virginia Tech supercomputer, put together from 1,100 Apple Macintosh 
computers, has been successfully tested in recent days, according to Jack 
Dongarra, a University of Tennessee computer scientist who maintains a 
listing of the world's 500 fastest machines.

The official results for the ranking will not be reported until next month 
at a supercomputer industry event. But the Apple-based supercomputer, which 
is powered by 2,200 I.B.M. microprocessors, was able to compute at 7.41 
trillion operations a second, a speed surpassed by only three other 
ultra-fast computers.

The fastest computers on the current Top 500 list are the Japanese Earth 
Simulator; a Los Alamos National Laboratory machine dedicated to weapons 
design; and another weapons oriented cluster of Intel Pentium 4 
microprocessors at the Lawrence Livermore National Laboratories.

Officials at the school said that they were still finalizing their results 
and that the final speed number might be significantly higher.

"We are demonstrating that you can build a very high performance machine 
for a fifth to a tenth of the cost of what supercomputers now cost," said 
Hassan Aref, the dean of the School of Engineering at Virginia Tech in 
Blacksburg, Va. The computer was put together in a virtual flash. 
Scientists from the school met with Apple executives two days after the 
company introduced its new 64-bit desktop computer in June.

Apple agreed to put the school at the head of the line for the new 
machines. Starting when they returned to school in September, student 
volunteers, who received free pizzas for their labor, helped with the 
assembly of the system, essentially an array of large refrigerators to keep 
the computers from overheating. Virginia Tech's president offered free 
football tickets to the technicians who were spending long hours on the 
project.

"When you have a small budget," said Srinidhi Varadarajan, a leader of the 
project, "you have to take risks."

The ranking is a coup for Apple, which for several years has lagged behind, 
in terms of raw computing speed, the PC world controlled by Intel and 
Advanced Micro Devices microprocessors. It is also an indication that the 
supercomputer industry, which has been in eclipse since the end of the cold 
war, is again playing a more vital role.

"On the surface this is a pretty impressive machine," Mr. Dongarra said. 
"It shows that the processors are getting to the point where this kind of 
performance will be quite common."

The performance of the new computer highlights the challenge to highly 
expensive custom-designed machines - like the Earth Simulator of Japan, 
which is assembled from 5,120 custom processors that have special circuitry 
for performing long strings of mathematical operations - from computers put 
together by linking more common off-the-shelf components in fairly simple 
ways.

The Japanese computer was measured at 35.8 trillion operations a second 
last year but American computer experts estimate that it cost as much as 
$250 million. By contrast, the fastest cluster machine, the Lawrence 
Livermore system consisting of 2304 Intel Xeon processors, is capable of 
7.63 trillion operations a second, at a price estimated at $10 million to 
$15 million. The Virginia Tech computer makes the cost-to-performance 
equation even starker.