Paul McMullin wants to reassure people that "we're not going to have satellites falling on our heads" because Intel Corp.'s Pentium chip has a flaw.
Still, the network administrator at the Johns Hopkins University's Applied Physics Laboratory said scientists at the high-tech center in Howard County are worried that the glitch could throw off critical calculations -- with potentially serious consequences.
"We do have people doing orbit estimate calculations, and those people are very concerned," said Dr. McMullin. "Knowing that the Pentium is flawed, they're switching their work to different processors."
From the Applied Physics Lab to computer dealers' showrooms, the shock waves from the discovery of a computational flaw in the Pentium are continuing to rattle Maryland computer users' confidence in Intel, the Santa Clara, Calif.-based company whose chips provide the silicon brains of 80 percent of the world's personal computers.
On the worldwide computer network called the Internet, the woes of the Pentium chip have been fodder for a barrage of jokes. (Example: What do you call the "Intel Inside" sticker on a Pentium-based computer? A warning label.)
But for many Pentium users in Maryland, the concern and the extra work caused by the flaw have been nothing to laugh about.
Compounding the problem has been the revelation that Intel knew about the flaw in July but acknowledged it only after a mathematician at Virginia's Lynchburg College discovered the bug in November and put the news out over the Internet.
Earlier this week, Intel suffered a serious blow when IBM Corp., a minor Pentium user but the best-known name in computers, said it would no longer ship machines with the flawed Pentium chips. Other manufacturers of Pentium-based computers, including Hewlett-Packard Corp. and Digital Equipment Corp., rallied round Intel, and yesterday Compaq Computer Corp., the world's largest seller of personal computers, announced that it too would continue to sell Pentium-based machines. But the damage has been done.
Since the flaw was revealed, Intel has insisted that the Pentium needs to be replaced only for users who perform the most advanced calculations. The company has set up a hot line staffed by people who quiz callers to determine whether they really need new chips.
But Pete Saybolt says you don't have to be a rocket scientist to know you need a new chip. The Towson-based stock market forecaster received a replacement Pentium this week, but the "cavalier attitude" he encountered still rankles.
"I had to do a fair amount of justification and screaming to get this chip replaced," said Mr. Saybolt, who uses a Pentium-equipped Packard Bell computer to perform his calculations for Laser Search Inc.
"It was about three weeks in doing," he said yesterday. "I had to prove that I need it."
Mr. Saybolt said his calculations require accuracy up to 20 places beyond the decimal point.
Intel has acknowledged that the flaw in its chip can cause errors in division problems as high as four places beyond the decimal point, but company spokesman Howard High said the chance of an error at that level is about 1 in 360 billion.
Dr. McMullin of the physics lab said that for administrative tasks, that flaw poses little risk. He said he has reassured office workers at the lab that they may continue to use their Pentium-based machines.
"We're talking about the pennies being wrong rather than the dollars being wrong in their spreadsheets," he said.
But for engineers or scientists doing such precise work as plotting a satellite's orbit, that type of flaw can be more serious than Intel has acknowledged because of a "compounding effect" in repeated calculations, said Dr. McMullin, who holds a doctorate in computer science.
"You have an error and the satellite moves a little off the first time you do the calculation and a little more the second time you do the calculation," he said. "Eventually [the scientist] has no confidence that the model is accurate."
Dr. McMullin said Intel should adopt a more liberal replacement policy.
At Trusted Information Systems Inc., a Glenwood company that produces Internet "firewall" software to protect computer systems from intruders, President Stephen T. Walker has adopted a more liberal replacement policy on his own.
Mr. Walker said his company will provide replacement Pentium chips to any customer who wants one as soon as they become available, even though the Pentium-driven software he sells isn't affected by the bug.
He said he hopes Intel will back him up but that Trusted is prepared to absorb the cost itself if necessary.
"We've heard from our firewall customers. Their problem is not a technical one but a perception one," Mr. Walker said.
"It used to be, saying your program is on a Pentium was a plus. Now they start to talk about all the problems out there."
Mr. High, the company spokesman, said the perceptions of Intel's response are dead wrong.
"Some of the issues are not technological but emotional," he said.
Glen Ricart, director of the University of Maryland's Computer Science Center, said he's in no hurry to get a replacement Pentium for his computer.
"I think I'll wait a bit for the furor to subside. I've been using my Pentium for months now without knowing an error existed," he said.