5 Most Embarrassing Software Bugs in History

I just realised that quite a few HN readers would have been young children in 1994 and so won't really know much about the Pentium FDIV bug.

It was a big thing! All software has bugs; most processors have bugs; so when this one was found Intel downplayed the seriousness of the bug. For the vast majority of users there would be no problem. Intel eventually agreed to replace the device for anyone who asked. But this software bug was reported widely, in mainstream media.

http://engineeringfailures.org/?p=466

This site has some nice technical information about it.

"The Pentium chip's math error (1993)"

Pretty sure that's a hardware bug.