View source for Unix Epoch

== Summary ==

The [http://www.unix.org Unix] Epoch is a different and unique way to represent dates.

== Description ==

This way of representing dates counts the seconds passed since the 1st of January 1970 at 00:00:00 in UTC (Greenwich timezone)

This date can be possitive (for dates after 1970-1-1) or negative (for dates before 1970-1-1).

The most interesting about this way of representing dates, is that dates are, for the first time, turned into numbers.

== Utility ==

Because it counts seconds since a very specific date, this way of representing dates is unique.

The "normal" way of representing dates is unique in a strange way, since there are various time zones and the same date represents different dates in different countries.

== Examples ==

{| border=3
|+ '''''[http://www.unix.org Unix] Epoch to Date conversion examples'''''
| '''[http://www.unix.org Unix] Epoch''' || '''Date'''
|-
| 252234223 || Thu, 29 Dec 1977 10:03:43 +0100
|-
| 1108486591 || Tue, 15 Feb 2005 17:56:31 +0100
|-
| 1101453443 || Fri, 26 Nov 2004 08:17:23 +0100
|-
| 0 || Thu, 01 Jan 1970 01:00:00 +0100
|-
| -234234234 || Mon, 30 Jul 1962 23:56:06 +0100
|-
| -1954864745 || Tue, 21 Jan 1908 06:00:55 +0100
|}

== Notes ==

The ''[http://www.unix.org Unix] Epoch'' date is also called ''[http://standards.ieee.org/regauth/posix POSIX] time'' or [http://www.unix.org Unix] time (or even simply ''Epoch'').

It was defined as a 4-bytes integer, so it handles dates from 1901 to 2038 only. Nowadays it is being decided to move it to an 8 bytes integer, so it will be able to handle all the dates through the whole universe's life.

[[aMule]] uses [http://www.unix.org Unix] Epoch dates in [[clients.met file]] and [[server.met file]] amongst other places. So you might want to take a look there to get a better idea of the [http://www.unix.org Unix] Epoch concept.