why the different MST7MDT zoneinfo files?
eggert at twinsun.com
Mon Dec 25 16:41:29 UTC 2000
> Date: Sun, 24 Dec 2000 10:41:17 -0500
> From: Ben Collins <bcollins at debian.org>
> I'm not too familiar with zoneinfo symantics, but I need to follow up on
> a Debian bug report. A user noticed these different MST7MDT zoneinfo
> files, and that the SystemV ones have the incorrect DST. Why are they
> different? Shouldn't the all be the same?
> f1937d0d3ed3a6cf9ca44e04cb4d8509 /usr/share/zoneinfo/MST7MDT
> f1937d0d3ed3a6cf9ca44e04cb4d8509 /usr/share/zoneinfo/posix/MST7MDT
> 1ac36e9eb32fbeb87af9921ba5b58850 /usr/share/zoneinfo/posix/SystemV/MST7MDT
> 65cbdc206e84bf90b10fabb30c13e9b1 /usr/share/zoneinfo/right/MST7MDT
> b4885b6a643d6a8c6e5e1f7de5180650 /usr/share/zoneinfo/right/SystemV/MST7MDT
> 1ac36e9eb32fbeb87af9921ba5b58850 /usr/share/zoneinfo/SystemV/MST7MDT
The SystemV stuff is for compatibility with ancient hosts, none of
which must be operating any more, as they mishandle US daylight saving
time past 1987. We should obsolete those entries, for the same reason
that US/Pacific-PET was removed in 1994: they are far more likely to
cause problems than to solve them.
The "posix" vs "right" difference is for leap second support.
"posix" ignores leap seconds, whereas "right" does not.
I suppose we shouldn't just remove the SystemV stuff right away, as
there might be some hosts that (mistakenly) use it. But my next
proposed patch can replace it with this for now:
Link America/Halifax SystemV/AST4ADT
Link America/New_York SystemV/EST5EDT
Link America/Chicago SystemV/CST6CDT
Link America/Denver SystemV/MST7MDT
Link America/Los_Angeles SystemV/PST8PDT
Link America/Anchorage SystemV/YST9YDT
Link America/Puerto_Rico SystemV/AST4
Link America/Indianapolis SystemV/EST5
Link America/Regina SystemV/CST6
Link America/Phoenix SystemV/MST7
Link Pacific/Pitcairn SystemV/PST8
Link Pacific/Gambier SystemV/YST9
Link America/Honolulu SystemV/HST10
More information about the tz