Intel works to fix Pentium bug that can crash systems

Intel engineers have worked all week on a fix for a newly discovered bug in the Pentium and Pentium MMX chips, but so far all they have accomplished is to verify that the bug exists. The problem occurs when a CPU runs a specific sequence of commands. The sequence can readily be fed into a computer, which then goes into a software loop and hangs up. A hardware reset is required to bring the machine back up again. Intel has joined hardware and software developers to find a solution to the problem, and is promising a further progress report today.

Intel engineers worked feverishly over the weekend tracking down a newly discovered bug in the Pentium and Pentium MMX chips, but so far all they have accomplished is to verify that the bug exists.

Intel has joined hardware and software developers to find a solution to the problem, according to a company representative.

"We're working hard on a workaround," the representative said.

Whatever the company uncovers will be published as an errata, he said. A progress report was expected today.

The problem occurs when a CPU runs a specific sequence of commands. The sequence can readily be fed into a computer, which then goes into a software loop and hangs up. A hardware reset is required to bring the machine back up again.

If the machine crashes while running Windows NT Server or Linux it is possible that disk writes will cease abruptly, possibly corrupting the file system, one system expert explained. A restore of the file system might be required to get the server back up and running, he said.

The problem does not affect Pentium Pro or Pentium II processors, the Intel representative noted.

The bug surfaced last week with an anonymous posting to an Internet newsgroup detailing how a programmer could use a certain opcode sequence to incite the Pentium bug. The posting garnered several replies, then was forwarded to the media.

Since the offending opcode sequence is illegal, it does not appear in commercial software, the Intel representative pointed out. For it to occur, someone has to intentionally program it into a computer, he noted.

It is unlikely that this piece of code could be run on a secure NT server unless the perpetrator had access to the console and had execute rights, the system expert explained. In an NT environment, it is possible that a remote client could hang up the server, he said.

The system expert said that in a Linux or other Unix system there is a greater chance that a remote user or client could hang up the machine since most of these machines are being used as a Web Servers and also offer many more ways for clients to run a piece of code on the server.

Intel Corp., in Santa Clara, California, can be reached at http://www.intel.com/.

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