November 1993 - tz - lists.iana.org

tzcode93g.tar.gz and tzdata93g.tar.gz
by ado Nov. 29, 1993

Nov. 29, 1993

The files tzcode93g.tar.gz and tzdata93g.tar.gz are now available for anonymous ftp from the ~ftp/pub directory on elsie.nci.nih.gov (128.231.16.1). Paul Eggert has provided a good deal of historic information (based on Shanks), and there are some code changes to deal with the buglets that crawled out in dealing with the new information. --ado

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Iceland's timezone
by yata!eggert＠twinsun.com Nov. 11, 1993

Nov. 11, 1993

From: Adam David <adam(a)veda.is> To: wollman(a)uvm-gen.emba.uvm.edu Date: Sat, 6 Nov 1993 21:50:43 +0000 (GMT) Iceland has not changed timezone since 1900 and has not had Summer Time since quite a long time ago, probably before 1970. If you want exact dates for summertime that long ago, I will find this out for you. I'm working on a rewrite of `europe' with a large set of historical data. My current draft (see below) claims that Iceland changed its timezone in 1968. I've taken this claim from Thomas G. Shanks, The international atlas (3rd edition), San Diego: ACS Publications, Inc. (1991). If you have some better data, please let me know. It would be nice to know what time zone abbreviations were used before 1968, since Shanks doesn't say. In the following table I've made up the names `IST', `IDT', `RMT', and `LMT' for Iceland Standard Time, Iceland Daylight Time, Reykjavik Mean Time, and Local Mean Time respectively. # Iceland # # From Adam David <adam(a)veda.is> (November 6, 1993): # The name of the timezone in Iceland for system / mail / news purposes is GMT. # # From Shanks (1991): # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Iceland 1908 only - Jan 1 0:00 0 S Rule Iceland 1917 1918 - Feb 20 2:00 1:00 D Rule Iceland 1917 only - Oct 25 2:00 0 S Rule Iceland 1918 1919 - Nov 15 2:00 0 S Rule Iceland 1919 only - Feb 19 2:00 1:00 D Rule Iceland 1921 only - Mar 19 2:00 1:00 D Rule Iceland 1921 only - Jun 22 2:00 0 S Rule Iceland 1941 1942 - Mar Sat>=1 2:00 1:00 D Rule Iceland 1941 1942 - Jul 2 2:00 0 S Rule Iceland 1943 1946 - Mar Sun>=1 2:00 1:00 D Rule Iceland 1943 1948 - Oct Sun>=22 2:00 0 S Rule Iceland 1947 1962 - Apr Sun>=1 2:00 1:00 D Rule Iceland 1949 only - Oct 30 2:00 0 S Rule Iceland 1950 only - Oct 22 2:00 0 S # From Paul Eggert <eggert(a)twinsun.com> (November 10, 1993): # Shanks's ``1953 Oct 26'' is probably a typo for Oct 25. # Likewise, correct Shanks's ``1961 Oct 22'' to Oct 29. Rule Iceland 1951 1967 - Oct Sun>=23 1:00s 0 S Rule Iceland 1963 1968 - Apr Sun>=1 1:00s 1:00 D # Zone NAME GMTOFF RULES/SAVE FORMAT [UNTIL] Zone Atlantic/Iceland/Reykjavik -1:27:24 - LMT 1837 Jan 1 -1:28 - RMT 1908 Jan 1 -1:00 Iceland I%sT 1968 Oct 27 1:00s 0:00 - GMT # This link is for backward compatibility with the old naming convention. Link Atlantic/Iceland/Reykjavik Iceland

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Re: Specifications for Iceland's timezone [forwarded]
by ado Nov. 9, 1993

Nov. 9, 1993

> From wollman(a)uvm-gen.EMBA.UVM.EDU Sat Nov 6 17:01:21 1993 > Return-Path: <wollman(a)uvm-gen.EMBA.UVM.EDU> > Received: from sadye.emba.uvm.edu by elsie.nci.nih.gov (4.1/SMI-4.1) > id AA20235; Sat, 6 Nov 93 17:01:19 EST > Received: by sadye.emba.uvm.edu id AA06301 > (5.65/1.23); Sat, 6 Nov 93 17:00:22 -0500 > Date: Sat, 6 Nov 93 17:00:22 -0500 > From: wollman(a)uvm-gen.EMBA.UVM.EDU > Message-Id: <9311062200.AA06301(a)sadye.emba.uvm.edu> > To: ado(a)elsie.nci.nih.gov > Subject: Specifications for Iceland's timezone > Status: RO > > One of the FreeBSD team members in Iceland reports the following > complaints with the default `Iceland' timezone as supplied in your > latest `europe' file: > > ------- Start of forwarded message ------- > From: Adam David <adam(a)veda.is> > To: wollman(a)uvm-gen.emba.uvm.edu > Subject: Re: New timezone code > Date: Sat, 6 Nov 1993 21:50:43 +0000 (GMT) > > [stuff deleted by me -GW] > > The problem with WET is that WET is used also in the British Isles, and > some systems might assume BST by default if they see "WET" during the summer > months. The name of the timezone in Iceland for system / mail / news purposes > is GMT. [...] > > > If Iceland has ever observed Summer Time or has changed time > > zones at any time in the past, I'd appreciate knowing about it, so we > > can update the files and send the corrections to Arthur David Olson. > > Iceland has not changed timezone since 1900 and has not had Summer Time > since quite a long time ago, probably before 1970. If you want exact dates > for summertime that long ago, I will find this out for you. > > [...] > ------- End of forwarded message ------- > > -GAWollman > > -- > Garrett A. Wollman | Shashish is simple, it's discreet, it's brief. ... > wollman(a)emba.uvm.edu | Shashish is the bonding of hearts in spite of distance. > uvm-gen!wollman | It is a bond more powerful than absence. We like people > UVM disagrees. | who like Shashish. - Claude McKenzie + Florent Vollant

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possible time zone file syntax extension
by ado Nov. 5, 1993

Nov. 5, 1993

There's work in progress on adding historical information to time zone files. It might be useful to extend the syntax of "UNTIL" parts so that you could write something such as # Zone NAME GMTOFF RULES/SAVE FORMAT [UNTIL] Zone This 0:00 - TST 1916 May 21 2:00s 0:00 Whatever T%sT 1968 Feb 18 2:00s->That where the "->That" on the final line means "after the UNTIL time, use whatever happens in Zone 'That'." This would both allow for more concise representation of historic information and allow a "-c" (or some other letter) flag to zic that would tell it to only compile "current" zones--zones that did NOT end with a line containing "->". If you have insights on whether this is the best thing to do, I'd love it if you'd share them with folks on the time zone mailing list. --ado

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