>The Unix epoch is midnight on January 1, 1970. It's important to remember that this isn't Unix's "birthday" -- rough versions of the operating system were around in the 1960s. Instead, the date was programmed into the system sometime in the early 70s only because it was convenient to do so, according to Dennis Ritchie, one the engineers who worked on Unix at Bell Labs at its inception.
>"At the time we didn't have tapes and we had a couple of file-systems running and we kept changing the origin of time," he said. "So finally we said, 'Let's pick one thing that's not going to overflow for a while.' 1970 seemed to be as good as any."
>"At the time we didn't have tapes and we had a couple of file-systems running and we kept changing the origin of time," he said. "So finally we said, 'Let's pick one thing that's not going to overflow for a while.' 1970 seemed to be as good as any."
https://www.wired.com/2001/09/unix-tick-tocks-to-a-billion/