A Sept. 29 Business article about a new IBM Corp. supercomputer misspelled the term "petaflop," a measure of computer speed. (Published 9/30/04)

IBM Corp. plans to announce today that it has built the world's fastest supercomputer at one of its facilities in Rochester, Minn., wresting the title from a system in Japan.

Dubbed the Blue Gene/L supercomputer, IBM's new system nudges past a nearly three-year-old computer speed record of 35.86 "teraflops," or trillions of calculations per second, with a working speed of 36.01 teraflops.

IBM's figures have not been verified by an outside party. But Horst Simon, one of four people responsible for publishing a respected tally of the world's 500 fastest supercomputers, said IBM typically offers conservative estimates of its system performances. "I trust [IBM's] numbers," he said.

The top 500 supercomputer list, posted at Top500.org, is updated twice a year; it is scheduled to be updated again in November.

The IBM system would mark the first time in three years that the world's fastest supercomputer is located in the United States. The current record-holder, known as the Earth Simulator, is a supercomputer in Yokohama, Japan, designed to simulate earthquakes.

"A lot of policymakers in Washington have worried about this as an exemplar of the U.S. computer industry falling behind," Dave Turek, an IBM vice president who oversees supercomputing efforts, said of the Earth Simulator. "But, by far, the great majority [of systems on the top 500 supercomputer list] have come from U.S.-led companies."

IBM plans to announce today that it is building a larger, and faster, version of the Blue Gene computer for the Lawrence Livermore National Laboratory in California, a project scheduled for completion in May 2005.

That lab's system will have a hypothetical peak speed of 360 teraflops, though the working top speed of the completed system will probably be 80 percent of that figure or less.

Lawrence Livermore lab has a "never-ending appetite" for computational power to help model molecular and nuclear behavior, Turek said. "Actually they need a pedaflop," he said, referring to a system capable of performing a quadrillion, or 1,000,000,000,000,000 calculations a second. "But we're getting there."

IBM says its new Blue Gene/L supercomputer can run more than 36 trillion calculations per second, faster than the current leader, the Earth Simulator, above, in Yokohama, Japan.