In article <41F77995.9070700@imperial.ac.uk>,
Keean Schupke
My vote goes for a TAI style time,
TAI time isn't usually available. System clocks are usually set to "Unix time", which is almost, but not quite, isomorphic with UTC. Sometimes they're set to a timezone-adjusted variant. I think conventional "best practice" is to have the system clock set to Unix time, synchronised by NTP. Together with its "leap-second bit", set for the day that will have the extra second, NTP time is unambiguous, even if Unix time isn't. This explains how NTP works with leap-seconds: http://www.eecis.udel.edu/~mills/leap.html
in milliseconds
This is not fine enough. The current System.Time uses picoseconds, for instance. -- Ashley Yakeley, Seattle WA