mar 28, 1945 - First actual case of bug being found
The word 'Bug' used in computers for errors and viruses, originally came from a woman called Grace Hopper on the 9th of September who first used the term 'Bug' when she was jokingly referring to the first actual computer of which had a moth stuck inbetweener the relay contacts of the Harvard Mark II computer. Grace Hopper helped to program the Harvard Mark II, and she also developed what is considered as the first compiler, the A-0.
Added to timeline:
History of Computing
1930's - 2000's