A small introduction is the Pentium FDIV bug – Wikipedia article which already has some of the highlights..
Ken Shirriff however went all the way in, and used a microscope to focus in on to the actual cause.
He wrote two Mastodon threads on it watching (most recent first, with a link to his blog post) making a good year’s end read:
- [Wayback/Archive] Ken Shirriff: “In 1994, a math professor disc…” – OldBytes Space – Mastodon
In 1994, a math professor discovered that Intel’s Pentium chip sometimes gave the wrong answer when dividing. Fixing this “FDIV” bug cost Intel $475 million. I analyzed the Pentium chip and found the bug. 1/N
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[Wayback/Archive] Intel’s $475 million error: the silicon behind the Pentium division bug
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- [Wayback/Archive] Ken Shirriff: “Intel launched the Pentium pro…” – OldBytes Space – Mastodon (9 posts)
In 1994, a math professor discovered that Intel’s Pentium chip sometimes gave the wrong answer when dividing. Fixing this “FDIV” bug cost Intel $475 million. I analyzed the Pentium chip and found the bug. 1/N
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And there is of course this, that predated his microscope work [Wayback/Archive] Ken Shirriff: “I recently saw an amazing Navajo rug…” – OldBytes Space – Mastodon Read the rest of this entry »






