School knits off-the-shelf Macs into third-fastest supercomputer

In a squat cement building at the outskirts of Virginia Tech's campus, 1,100 Macintosh PCs are stacked like library books on metal racks that students helped arrange in return for football tickets and pizza.

The cluster of off-the-shelf G5 Power Macs was assembled in a few weeks for about $7 million. That is significantly less money than the custom supercomputers that research labs use for weather and weapons simulations, drug experiments and other highly complex projects.

Dongarra, who will release the 2003 rankings on Nov. 17, said he expects the only faster supercomputers to be the Earth Simulator Center in Japan, which cost at least $250 million and has been clocked at 33.9 trillion operations per second; and a computer at Los Alamos National Laboratory (clocked at 13.9 trillion operations per second) made by Hewlett-Packard Co. for $215 million.

Each of the 1,100 Macs has two IBM PowerPC 970 microprocessors that are based on a relatively new 64-bit design, which means they process data in chunks of 64 bits -- a method exponentially faster than older, 32-bit technology. The processors, running Mac OS X, are connected by a high-speed network called Infiniband that allows them to break up major calculations and analyze each part at the same time.

Apple, which has had little presence in the supercomputing industry, was reluctant, he said, but "we persuaded them that we could make it work." Virginia Tech spent about $5 million on the Apple computers and another $2 million renovating the building that would house them, Aref said.