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From: dgr...@sti.com (Dan R. Greening)
Newsgroups: comp.std.internat
Subject: Time Zone Abbreviation Standards?
Message-ID: <1991Sep6.195121.14111@sti.com>
Date: 6 Sep 91 19:51:21 GMT
Organization: Software Transformation, Inc.
Lines: 8

Are there any international time zone abbreviation standards?  USA has
"PST", "PDT", etc.  

Thanks.
-- 
____
\  /Dan Greening    Software Transformation   1601 Saratoga-Sunnyvale Rd, #100
 \/dgr...@sti.com   (408) 973-8081 x313       Cupertino, CA 95014

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From: egg...@twinsun.com (Paul Eggert)
Newsgroups: comp.std.internat
Subject: Re: Time Zone Abbreviation Standards?
Message-ID: <1991Sep10.213213.12048@twinsun.com>
Date: 10 Sep 91 21:32:13 GMT
References: <1991Sep6.195121.14111@sti.com>
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There is no official standard.  I've heard rumors of one in the works, but
can't remember the details, and don't envy the standardizers.  Part of the
problem is which character set to use: not all abbreviations can be represented
in ISO Latin-1.  But the main problem is that the names are political, not
technical, so the rules are always changing and are often in dispute.  For
example, the Soviet Union changed their daylight savings time rules this March
but some of the rebellious republics ignored the new rules, and other areas
changed their clocks in the opposite direction of the directive from Moscow.

Your best bet if you get to design the format are to use numeric offsets like
the `-0500' of Internet RFC 822, and to avoid ambiguous abbreviations like EST,
where the E can stand for Eastern US or Eastern Brazil (or Easter Island!).
However, if you really want to wade into the swamp of names like GMT, UTC, UT,
and CUT (all of which mean the same thing), some unofficial `standards' are:

	Arthur Olson and Guy Harris's public domain timezone implementation,
	e.g. see /usr/share/lib/zoneinfo/[a-z]* in SunOS 4.1.1.
	This is by far the most authoritative automated list,
	and contains not only the names but (what is just as important)
	a historical database of when names and rules changed.

	Unix getdate().  At least two free versions are available.
	One is by Bellovin, Salz, and Berets.
	The other, by Moraes, is in the source code to C News 27-Aug-1991.

	The source code to RCS 5.5 has a list in src/partime.c.

	The Multics source code has a list of time zones.

You can also look in non-computer reference books.  The Multics hackers used:

	_The Astrology Annual Reference Book, 1981_
		by Marcian B. MacGregor and Zipporah Pottenger Dobyns
	_The American Ephemeris, 1971 to 1980_, by Neil F Michelsen

Don't laugh too hard at Multics being based on astrology -- before computers,
astrologers were the people most interested in knowing exactly which time zone
you were born in, and kept better records than many other sources.  However,
printed sources like these tend to hopelessly out of date for computer
applications; they contain many (ambiguous) time zone names that probably
haven't been used for half a century.

Path: gmdzi!unido!mcsun!uunet!auspex!guy
From: g...@auspex.auspex.com (Guy Harris)
Newsgroups: comp.std.internat
Subject: Re: Time Zone Abbreviation Standards?
Message-ID: <9943@auspex.auspex.com>
Date: 11 Sep 91 17:49:46 GMT
References: <1991Sep6.195121.14111@sti.com> <1991Sep10.213213.12048@twinsun.com>
Organization: Auspex Systems, Santa Clara
Lines: 14

>	Arthur Olson and Guy Harris's public domain timezone implementation,

Credit where credit is due, please.  Arthur and I were most definitely
*not* the only creators of that package, and my contribution isn't
larger than that of every one of the contributors other than Arthur;
other contributors include Robert Elz (from whose code the
"timelocal()"/"mktime()" stuff came, based on an idea of Bob Kridle) and
Bradley White (author of the leap-second support), and a cast of
thousands who contributed time zone information, including Bob Devine.

The bulk of the code is either from Arthur, or was significantly
modified by him, and Arthur came up with the original idea in the course
of a discussion with Mark Horton.  As such, I just call it "the Arthur
Olson time zone code".