The overall system, which cost more than $1m (£0.54m), consists of eight p655 machines, each with eight 1.5GHz Power4+ processors, and one p690 with 32 1.7GHz Power4+ processors, according to IBM and the university.
The p690 runs a simulation of the Earth's ocean, while the p655 systems model the Earth's land, atmosphere and sea ice, said Charlie Zender, assistant professor of Earth system science at the university. One of the p655 systems shares data among the individual simulations.
The system will be used to examine issues such as how sensitive the climate is to effects such as soot from car exhaust settling on snowfields, Zender said. It also will be used to test the models themselves by comparing what they forecast with what actually takes place in the real world.
IBM has been gaining in supercomputer market share. Its competitors include Hewlett-Packard, Cray, Dell and Sun Microsystems.
The system offers a freeze-frame of the changing world of high-performance technical computing. Irvine's project doesn't tap into one trend -- "Beowulf" clusters made of a large number of independent but networked Linux machines that divide a calculation job -- but it will tap into another: the use of the Linux operating system.
Clustered machines, such as Virginia Polytechnic Institute's Apple G5 supercomputer or Sandia National Laboratories' upcoming Cray-based Red Storm are catching on in the supercomputing realm, growing more common on the top 500 list of the most powerful supercomputers.
"Beowulf works fine on many problems, but it doesn't work here," Zender said. Each of Irvine's simulations requires a single operating system and a single pool of memory, he said.
At Irvine, each machine runs the AIX operating system, which is IBM's version of Unix. However, Zender said, the company plans to move one machine to Linux in a year.
IBM's pSeries machines historically have run AIX only, but Big Blue has begun aggressively pushing Linux.
The Irvine researchers would prefer Linux, he said. "If we can get the same throughput... then it makes more sense to go with Linux, because the support costs drop dramatically and because the users are more familiar with Linux -- we all have Linux on our laptops and workstations," Zender said.
When evaluating competing bids, "two of the proposed systems were Linux-based systems, but the benchmarks didn't pan out," Zender said. "It was a case of not-quite-ready for prime time."
Specifically, Zender said Linux wasn't yet good enough in handling multiple threads -- sequences of programming instructions that execute in parallel. "Turns out that the threading in the 2.4 [Linux] kernel was not up to snuff," he said. "There's a lot of hope that the 2.6 kernel will work for our type of application."
AIX and Linux are tangled in a lawsuit by the SCO Group, but Zender wasn't fazed by the legal action.
SCO asserts that IBM breached its Unix contract with SCO by moving Unix intellectual property into Linux; says IBM's licence to ship AIX is no longer valid; and seeks licence fees from Linux users.
"It's a laughable lawsuit. It will certainly be resolved sometime in the next decade, and they'll be exposed for the frauds that they are," Zender said.
SCO spokesman Marc Modersitzki said the company believes it's not acting fraudulently. "SCO owns Unix copyrights, and we're working to protect them," he said. "We feel like we're going about this in the proper way, but I recognise that there are those that disagree."
