On Sun, 8 Mar 2015 17:09:59 +0000, Zefram wrote: > Brooks Harris wrote: >> It seems to me NTP and POSIX as well as other timescales concerned >> with "civil time", are essentially disconnected from "reality", >> expressing "idealized" measurement scales. > > That's very much what they're not. TT is idealised, and TAI less so. > >> I >> think none of the "civil" timescales are counting in UT - they are >> measured in SI Seconds, even when prolpetic to 1972. > > NTP doesn't deal with pre-1972 time at all. (No, the nominal epoch > doesn't count.) > > POSIX time_t notionally can represent pre-1972 times, but in practice no > Unix system of that era was synchronised to UTC. Any use of time_t for > precise pre-1972 time is heavily retrospective, and the interpretation > is more governed by the application than by the POSIX standard. Wild > pre-1972 Unix time_t values heavily predate the POSIX standard, and their > interpretation has little to do with UTC. They are understood to be vague > UT with usually very poor synchronisation (via the operator's wristwatch).
The actual timescale in POSIX is a found to Seconds Since the Epoch, and fractions thereof. Negative values are not currently defined. Joe Gwinn _______________________________________________ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs