Few famous bugs of their times...
http://en.wikipedia.org/wiki/Killer_poke
http://en.wikipedia.org/wiki/Cyrix_coma_bug
http://en.wikipedia.org/wiki/F00f
http://en.wikipedia.org/wiki/Pentium_FDIV_bug
Link to Thomas R. Nicely's (person who discovered FDIV bug and reported to Intel) page
http://www.trnicely.net/#PENT
Original e-mail message announcing the discovery of the Pentium divison flaw, 30 October 1994
http://www.trnicely.net/pentbug/bugmail1.html
and FAQ for that
http://www.trnicely.net/pentbug/pentbug.html
Some more generic bugs...
http://en.wikipedia.org/wiki/Off_by_one_error
..and some unusual bugs :)
http://en.wikipedia.org/wiki/Unusual_software_bug
And this is what happens to your code and data over time...
http://en.wikipedia.org/wiki/Bit_rot
