January 1, 1970

1. When the Big Bang occured according to a Unix computer system. This date is when the first Unix computer was made operable. If you find a file that was from Wed Dec 31, 1969 on your Linux PC, you can be sure that the date on that file got knackered. 2. A date to utter when something hasn't been done in a long time, referring to the idea that January 1, 1970 is the "beginning of time". Used when something seems like it hasn't been done since the beginning of time.