[tz] Looking for details on timezones “right/…”

Steve Allen sla at ucolick.org
Wed Jan 18 03:39:17 UTC 2023


On Tue 2023-01-17T17:56:17-0700 Paul Gilmartin via tz hath writ:
> I have not experimented with TZ=right/* for dates prior to 1972.
>     <http://leapsecond.com/java/gpsclock.htm>

IBM should assume no leap seconds, but because the old UTC frequency
offset between 1970 and 1972 was 300e-10 that means at 1970
the difference TAI-UTC was 8.000082 s  as shown in

https://www.ucolick.org/~sla/leapsecs/deltat.html#amscidelt.png

"right" timezones assume a unix system clock which was TAI - 10 s at
1970 and that SI seconds have been counted since at 1970, but that is
not how people actually set their clocks.

--
Steve Allen                    <sla at ucolick.org>              WGS-84 (GPS)
UCO/Lick Observatory--ISB 260  Natural Sciences II, Room 165  Lat  +36.99855
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