The current Unix-Timestamp:
What is the Unix-Timestamp?
The Unix time was developed 1969 for the operating system Unix and fixed as POSIX standard. Before Unix version 6, the Unixtime counted in hundredths of a second, so the epoch had to be redefined every year. Since Unix version 6 it counts the seconds since Thursday, January 1, 1970 00:00 UTC. This date is also called The Epoch.