Intel Checking Possible Pentium II Math Flaw

Intel Corp. on Tuesday tried to figure out a reported math flaw in its Pentium II microprocessor as it prepared to launch the newest generation of its flagship computer chip.

Intel, the world’s largest maker of computer chips, said it expected to learn if the problem was genuine by the end of the week. The company also said it would figure out how the flaw might affect personal computer users and come up with a solution as soon as possible.

Meanwhile, Intel planned to tell the public about the potential error on its web site, probably on Wednesday.

The company’s reaction was in sharp contrast to how it handled a math flaw in an earlier version of the Pentium processor in 1994. Intel first tried to keep that flaw quiet and forced customers to justify their need for a new chip, before reversing its policy.

“I think Intel’s matured enormously from the earlier Pentium experience,” said Robert Chaplinski, an analyst with Hambrecht & Quist in San Francisco. “They have become sensitive to the consumer, and I think they’ll do whatever it takes to clearly fix the problem.”

The news hurt Intel’s stock, sending it down $4.50 to close at $158 on the Nasdaq Stock Market.

The apparent bug was reported Monday on the Internet web site, “Intel Secrets: What Intel Doesn’t Want You to Know,” published by company critic Robert Collins. Intel, based in Santa Clara, Calif., had not discovered the bug while testing Pentium II, which it is introducing in New York on Wednesday.

Collins, a software engineer in San Jose, said a computer user he identified only as “Dan” told him of a problem with the Pentium Pro processor, the next generation chip after Pentium. Pentium II uses much of the Pentium Pro’s technology.

Running his own test with both chips, Collins found they sometimes made errors in some floating-point operations, complex calculations used commonly in spreadsheets and computer-aided design. The chip, in order to save space and memory, sometimes handles numbers in different ways.

The problem, Collins said, is that the processor occasionally fails to tell the software program of the change, resulting in errors.

“I put this out for peer review,” said Collins. “I’m asking if it really is a bug. . . . I really wanted the numerical analysts to look into this and debate its significance.”

Some computer users whose machines use Pentium Pro chips posted messages on Collins’ site, saying they used his test and found similar errors. Some expressed concern that the flaw could affect their work and wondered how Intel would respond.

While Intel and Chaplinski said it was too early to tell how serious the bug might be, other industry analysts said it appeared to be technically minor and could likely be fixed with a software “patch.”

They pointed out that no one has reported any problems with the Pentium Pro chip, which has been in PCs for 18 months.