the Pentium FDIV bug

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programmingops culture

A 1994 flaw in the Intel Pentium that returned slightly wrong answers for certain floating-point divisions.

Mathematician Thomas Nicely spotted the error in a lookup table, and Intel's initial offer to replace chips only for those who could prove they were affected caused a public-relations disaster. Intel reversed course, took a charge of roughly 475 million dollars, and the episode reset how the industry handles hardware errata.

Also known as: FDIV bug, Pentium bug, Intel FDIV

Sources

Nicely (1994); Intel Q4 1994 charge (~US$475M)

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