ftp://ftp.iana.org/tz/data/leapseconds
http://en.wikipedia.org/wiki/Unix_time
"Unix time, (...) is (...) defined as the number of seconds elapsed since midnight Coordinated Universal Time (UTC) of Thursday, January 1, 1970 (...) not counting leap seconds"
Microsoft apparently rejected the idea of using leap seconds because Windows just isn't accurate enough:
The W32Time service uses the Network Time Protocol (NTP) in
Microsoft Windows Server 2003, in Windows Server 2003 R2,
in Windows Server 2008, and in Windows Server 2008 R2.
...
The W32Time service cannot reliably maintain sync time to
the range of 1 to 2 seconds. Such tolerances are outside
the design specification of the W32Time service.
Unix/Linux computers don't, Windows computers don't, GPS doesn't:
http://en.wikipedia.org/wiki/Global_Positioning_System#Timek...
GPS Time is designated as being coincident with UTC
(USNO) at the start date of January 6, 1980 (00 hours).
GPS Time does not count leap seconds, and therefore an
offset exists between UTC (USNO) and GPS Time (at this
date in April 2007: 14 seconds).
Unlike GPS, the GLONASS time scale is not continuous and
must be adjusted for periodic leap seconds. Leap seconds
are applied to all UTC time references as specified by
the International Earth Rotation and Reference System
Service (IERS). Leap seconds are used to keep UTC close
to mean solar time. Mean solar time, based on the spin of
the Earth on its axis, is not uniform and its rate is
gradually changing due to tidal friction and other
factors such as motions of the Earth's fluid core.
This is the best overview I've seen of all the pros/cons with regard to UTC and whether leap seconds should be abolished:
http://www.agi.com/downloads/resources/user-resources/downlo...
Basically, much in the same way that we all despise DST (or date differences between Julian/Gregorian calendars), a certain part of me wants to know, if we humans last on this planet long enough, that our descendants thousands of years from now won't look back and curse at us for being idiots and deviating from celestial time.