Here are proposed changes to the tz database, spurred by Ephraim Silverberg's report about Israel. Changes to near-future time stamps: * Israel has revamped its daylight-saving rules this year, which means the unpatched tz database will mishandle time stamps starting April 1. Thanks to Ephraim Silverberg for the detailed analysis (including Emacs source code!). Changes to past time stamps: * Fix a glitch for time stamps in Azerbaijan on 1992-09-26. Thanks to Klaus Schmid for reporting the problem. Changes to commentary: * Irish laws relating to time zones and daylight-saving time are available on the web. Thanks to Joseph S. Myers for this info. * Pan Am used some unusual time zone designations for Midway in 1936. Thanks to Mark Brader for this info. Changes to the tz-link.htm web page: * Mention Unicode's CLDR project. Thanks to Mark Davis for mentioning CLDR. Also, point at the current time zone table for CLDR, and update some obsolete references to ICU. * Mention some problems with numeric time zone abbreviations. Thanks to Peter Thoeny for mentioning the confusions in this area. * Use <abbr> and <code> more systematically. =================================================================== RCS file: RCS/asia,v retrieving revision 2005.5 retrieving revision 2005.5.0.2 diff -pu -r2005.5 -r2005.5.0.2 --- asia 2005/02/07 21:19:41 2005.5 +++ asia 2005/02/22 22:49:40 2005.5.0.2 @@ -107,7 +107,7 @@ Zone Asia/Baku 3:19:24 - LMT 1924 May 2 3:00 - BAKT 1957 Mar # Baku Time 4:00 RussiaAsia BAK%sT 1991 Mar 31 2:00s 3:00 1:00 BAKST 1991 Aug 30 # independence - 3:00 RussiaAsia AZ%sT 1992 Sep lastSun 2:00s + 3:00 RussiaAsia AZ%sT 1992 Sep lastSat 23:00 4:00 - AZT 1996 # Azerbaijan time 4:00 EUAsia AZ%sT 1997 4:00 Azer AZ%sT @@ -639,7 +639,8 @@ Rule Zion 1988 only - Apr 9 0:00 1:00 D Rule Zion 1988 only - Sep 3 0:00 0 S # From Ephraim Silverberg <ephraim@cs.huji.ac.il> -# (1997-03-04, 1998-03-16, 1998-12-28, 2000-01-17, 2000-07-25, and 2004-12-22): +# (1997-03-04, 1998-03-16, 1998-12-28, 2000-01-17, 2000-07-25, 2004-12-22, +# and 2005-02-17): # According to the Office of the Secretary General of the Ministry of # Interior, there is NO set rule for Daylight-Savings/Standard time changes. @@ -735,91 +736,74 @@ Rule Zion 2003 only - Oct 3 1:00 0 S Rule Zion 2004 only - Apr 7 1:00 1:00 D Rule Zion 2004 only - Sep 22 1:00 0 S -# Yesterday, the Knesset Interior Committee passed a proposed (originally -# in March 2004) change to the Time Setting Law that would make the dates -# for DST from 2005 and beyond so that DST starts on the night _after_ the -# first night of the Passover holiday at midnight until midnight of the -# Saturday night _before_ the fast of Yom Kippur. -# -# Those who can read Hebrew can view the proposal at: -# -# ftp://ftp.cs.huji.ac.il/pub/tz/announcements/2005+.ps -# -# The proposal still has to be passed by the Knesset (three readings) for -# it to become law.... - -# From Paul Eggert (2004-12-22): -# For now, guess that the rules proposed on 2004-12-20 will be adopted. -# This is quite possibly wrong, but it is more likely than no DST at all. -# I used Ed Reingold's cal-hebrew in GNU Emacs 21.3, along with code -# written by Ephraim Silverberg, to generate this list. -# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S -Rule Zion 2005 only - Apr 25 0:00 1:00 D -Rule Zion 2005 only - Oct 9 0:00 0 S -Rule Zion 2006 only - Apr 14 0:00 1:00 D -Rule Zion 2006 only - Oct 1 0:00 0 S -Rule Zion 2007 only - Apr 4 0:00 1:00 D -Rule Zion 2007 only - Sep 16 0:00 0 S -Rule Zion 2008 only - Apr 21 0:00 1:00 D -Rule Zion 2008 only - Oct 5 0:00 0 S -Rule Zion 2009 only - Apr 10 0:00 1:00 D -Rule Zion 2009 only - Sep 27 0:00 0 S -Rule Zion 2010 only - Mar 31 0:00 1:00 D -Rule Zion 2010 only - Sep 12 0:00 0 S -Rule Zion 2011 only - Apr 20 0:00 1:00 D -Rule Zion 2011 only - Oct 2 0:00 0 S -Rule Zion 2012 only - Apr 8 0:00 1:00 D -Rule Zion 2012 only - Sep 23 0:00 0 S -Rule Zion 2013 only - Mar 27 0:00 1:00 D -Rule Zion 2013 only - Sep 8 0:00 0 S -Rule Zion 2014 only - Apr 16 0:00 1:00 D -Rule Zion 2014 only - Sep 28 0:00 0 S -Rule Zion 2015 only - Apr 5 0:00 1:00 D -Rule Zion 2015 only - Sep 20 0:00 0 S -Rule Zion 2016 only - Apr 24 0:00 1:00 D -Rule Zion 2016 only - Oct 9 0:00 0 S -Rule Zion 2017 only - Apr 12 0:00 1:00 D -Rule Zion 2017 only - Sep 24 0:00 0 S -Rule Zion 2018 only - Apr 1 0:00 1:00 D -Rule Zion 2018 only - Sep 16 0:00 0 S -Rule Zion 2019 only - Apr 21 0:00 1:00 D -Rule Zion 2019 only - Oct 6 0:00 0 S -Rule Zion 2020 only - Apr 10 0:00 1:00 D -Rule Zion 2020 only - Sep 27 0:00 0 S -Rule Zion 2021 only - Mar 29 0:00 1:00 D -Rule Zion 2021 only - Sep 12 0:00 0 S -Rule Zion 2022 only - Apr 17 0:00 1:00 D -Rule Zion 2022 only - Oct 2 0:00 0 S -Rule Zion 2023 only - Apr 7 0:00 1:00 D -Rule Zion 2023 only - Sep 24 0:00 0 S -Rule Zion 2024 only - Apr 24 0:00 1:00 D -Rule Zion 2024 only - Oct 6 0:00 0 S -Rule Zion 2025 only - Apr 14 0:00 1:00 D -Rule Zion 2025 only - Sep 28 0:00 0 S -Rule Zion 2026 only - Apr 3 0:00 1:00 D -Rule Zion 2026 only - Sep 20 0:00 0 S -Rule Zion 2027 only - Apr 23 0:00 1:00 D -Rule Zion 2027 only - Oct 10 0:00 0 S -Rule Zion 2028 only - Apr 12 0:00 1:00 D -Rule Zion 2028 only - Sep 24 0:00 0 S -Rule Zion 2029 only - Apr 1 0:00 1:00 D -Rule Zion 2029 only - Sep 16 0:00 0 S -Rule Zion 2030 only - Apr 19 0:00 1:00 D -Rule Zion 2030 only - Oct 6 0:00 0 S -Rule Zion 2031 only - Apr 9 0:00 1:00 D -Rule Zion 2031 only - Sep 21 0:00 0 S -Rule Zion 2032 only - Mar 28 0:00 1:00 D -Rule Zion 2032 only - Sep 12 0:00 0 S -Rule Zion 2033 only - Apr 15 0:00 1:00 D -Rule Zion 2033 only - Oct 2 0:00 0 S -Rule Zion 2034 only - Apr 5 0:00 1:00 D -Rule Zion 2034 only - Sep 17 0:00 0 S -Rule Zion 2035 only - Apr 25 0:00 1:00 D -Rule Zion 2035 only - Oct 7 0:00 0 S -Rule Zion 2036 only - Apr 13 0:00 1:00 D -Rule Zion 2036 only - Sep 28 0:00 0 S -Rule Zion 2037 only - Apr 1 0:00 1:00 D -Rule Zion 2037 only - Sep 13 0:00 0 S +# The proposed law agreed upon by the Knesset Interior Committee on +# 2005-02-14 is that, for 2005 and beyond, DST starts at 02:00 the +# last Friday before April 2nd (i.e. the last Friday in March or April +# 1st itself if it falls on a Friday) and ends at 02:00 on the Saturday +# night _before_ the fast of Yom Kippur. +# +# Those who can read Hebrew can view the announcement at: +# +# ftp://ftp.cs.huji.ac.il/pub/tz/announcements/2005+beyond.ps + +# From Paul Eggert (2005-02-22): +# I used Ephraim Silverberg's dst-israel.el program +# <ftp://ftp.cs.huji.ac.il/pub/tz/software/dst-israel.el> (2005-02-20) +# along with Ed Reingold's cal-hebrew in GNU Emacs 21.4, +# to generate the transitions in this list. +# (I replaced "lastFri" with "Fri>=26" by hand.) +# The spring transitions below all correspond to the following Rule: +# +# Rule Zion 2005 max - Mar Fri>=26 2:00 1:00 D +# +# but older zic implementations (e.g., Solaris 8) do not support +# "Fri>=26" to mean April 1 in years like 2005, so for now we list the +# springtime transitions explicitly. + +# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S +Rule Zion 2005 only - Apr 1 2:00 1:00 D +Rule Zion 2005 only - Oct 9 2:00 0 S +Rule Zion 2006 2010 - Mar Fri>=26 2:00 1:00 D +Rule Zion 2006 only - Oct 1 2:00 0 S +Rule Zion 2007 only - Sep 16 2:00 0 S +Rule Zion 2008 only - Oct 5 2:00 0 S +Rule Zion 2009 only - Sep 27 2:00 0 S +Rule Zion 2010 only - Sep 12 2:00 0 S +Rule Zion 2011 only - Apr 1 2:00 1:00 D +Rule Zion 2011 only - Oct 2 2:00 0 S +Rule Zion 2012 2015 - Mar Fri>=26 2:00 1:00 D +Rule Zion 2012 only - Sep 23 2:00 0 S +Rule Zion 2013 only - Sep 8 2:00 0 S +Rule Zion 2014 only - Sep 28 2:00 0 S +Rule Zion 2015 only - Sep 20 2:00 0 S +Rule Zion 2016 only - Apr 1 2:00 1:00 D +Rule Zion 2016 only - Oct 9 2:00 0 S +Rule Zion 2017 2021 - Mar Fri>=26 2:00 1:00 D +Rule Zion 2017 only - Sep 24 2:00 0 S +Rule Zion 2018 only - Sep 16 2:00 0 S +Rule Zion 2019 only - Oct 6 2:00 0 S +Rule Zion 2020 only - Sep 27 2:00 0 S +Rule Zion 2021 only - Sep 12 2:00 0 S +Rule Zion 2022 only - Apr 1 2:00 1:00 D +Rule Zion 2022 only - Oct 2 2:00 0 S +Rule Zion 2023 2032 - Mar Fri>=26 2:00 1:00 D +Rule Zion 2023 only - Sep 24 2:00 0 S +Rule Zion 2024 only - Oct 6 2:00 0 S +Rule Zion 2025 only - Sep 28 2:00 0 S +Rule Zion 2026 only - Sep 20 2:00 0 S +Rule Zion 2027 only - Oct 10 2:00 0 S +Rule Zion 2028 only - Sep 24 2:00 0 S +Rule Zion 2029 only - Sep 16 2:00 0 S +Rule Zion 2030 only - Oct 6 2:00 0 S +Rule Zion 2031 only - Sep 21 2:00 0 S +Rule Zion 2032 only - Sep 12 2:00 0 S +Rule Zion 2033 only - Apr 1 2:00 1:00 D +Rule Zion 2033 only - Oct 2 2:00 0 S +Rule Zion 2034 2037 - Mar Fri>=26 2:00 1:00 D +Rule Zion 2034 only - Sep 17 2:00 0 S +Rule Zion 2035 only - Oct 7 2:00 0 S +Rule Zion 2036 only - Sep 28 2:00 0 S +Rule Zion 2037 only - Sep 13 2:00 0 S # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Asia/Jerusalem 2:20:56 - LMT 1880 =================================================================== RCS file: RCS/australasia,v retrieving revision 2003.4 retrieving revision 2003.4.0.1 diff -pu -r2003.4 -r2003.4.0.1 --- australasia 2003/10/06 13:32:20 2003.4 +++ australasia 2005/02/22 22:51:26 2003.4.0.1 @@ -434,6 +434,17 @@ Zone Pacific/Johnston -10:00 - HST # uninhabited # Midway +# +# From Mark Brader (2005-01-23): +# [Fallacies and Fantasies of Air Transport History, by R.E.G. Davies, +# published 1994 by Paladwr Press, McLean, VA, USA; ISBN 0-9626483-5-3] +# reproduced a Pan American Airways timeables from 1936, for their weekly +# "Orient Express" flights between San Francisco and Manila, and connecting +# flights to Chicago and the US East Coast. As it uses some time zone +# designations that I've never seen before:.... +# Fri. 6:30A Lv. HONOLOLU (Pearl Harbor), H.I. H.L.T. Ar. 5:30P Sun. +# " 3:00P Ar. MIDWAY ISLAND . . . . . . . . . M.L.T. Lv. 6:00A " +# Zone Pacific/Midway -11:49:28 - LMT 1901 -11:00 - NST 1956 Jun 3 -11:00 1:00 NDT 1956 Sep 2 =================================================================== RCS file: RCS/europe,v retrieving revision 2005.3 retrieving revision 2005.3.0.1 diff -pu -r2005.3 -r2005.3.0.1 --- europe 2005/01/17 23:36:17 2005.3 +++ europe 2005/02/22 22:50:34 2005.3.0.1 @@ -255,6 +255,35 @@ # "Timeball on the ballast office is down. Dunsink time." # -- James Joyce, Ulysses +# From Joseph S. Myers (2005-01-26): +# Irish laws are available online at www.irishstatutebook.ie. These include +# various relating to legal time, for example: +# +# ZZA13Y1923.html ZZA12Y1924.html ZZA8Y1925.html ZZSIV20PG1267.html +# +# ZZSI71Y1947.html ZZSI128Y1948.html ZZSI23Y1949.html ZZSI41Y1950.html +# ZZSI27Y1951.html ZZSI73Y1952.html +# +# ZZSI11Y1961.html ZZSI232Y1961.html ZZSI182Y1962.html +# ZZSI167Y1963.html ZZSI257Y1964.html ZZSI198Y1967.html +# ZZA23Y1968.html ZZA17Y1971.html +# +# ZZSI67Y1981.html ZZSI212Y1982.html ZZSI45Y1986.html +# ZZSI264Y1988.html ZZSI52Y1990.html ZZSI371Y1992.html +# ZZSI395Y1994.html ZZSI484Y1997.html ZZSI506Y2001.html +# +# [These are all relative to the root, e.g., the first is +# <http://www.irishstatutebook.ie/ZZA13Y1923.html>.] +# +# (These are those I found, but there could be more. In any case these +# should allow various updates to the comments in the europe file to cover +# the laws applicable in Ireland.) +# +# (Note that the time in the Republic of Ireland since 1968 has been defined +# in terms of standard time being GMT+1 with a period of winter time when it +# is GMT, rather than standard time being GMT with a period of summer time +# being GMT+1.) + # From Paul Eggert (1999-03-28): # Clive Feather (<news:859845706.26043.0@office.demon.net>, 1997-03-31) # reports that Folkestone (Cheriton) Shuttle Terminal uses Concession Time =================================================================== RCS file: RCS/tz-link.htm,v retrieving revision 2005.3 retrieving revision 2005.3.0.1 diff -pu -r2005.3 -r2005.3.0.1 --- tz-link.htm 2005/01/17 23:36:19 2005.3 +++ tz-link.htm 2005/02/22 23:10:33 2005.3.0.1 @@ -36,9 +36,9 @@ This database (often called <code>tz</co is used by several implementations, including <a href="http://www.gnu.org/software/libc/">the -<acronym title="GNU's Not Unix">GNU</acronym> +<abbr title="GNU's Not Unix">GNU</abbr> C Library</a> used in -<a href="http://www.linux.org/"><acronym>GNU</acronym>/Linux</a>, +<a href="http://www.linux.org/"><abbr>GNU</abbr>/Linux</a>, <a href="http://www.freebsd.org/">FreeBSD</a>, <a href="http://www.netbsd.org/">NetBSD</a>, <a href="http://www.openbsd.org/">OpenBSD</a>, @@ -80,7 +80,7 @@ where <code><var>C</var></code> is the c similarly, the data are in <code>tzdata<var>D</var>.tar.gz</code>, where <code><var>D</var></code> is the data's version. The following shell commands download -these files to a <acronym>GNU</acronym>/Linux or similar host; +these files to a <abbr>GNU</abbr>/Linux or similar host; see the downloaded <code>README</code> file for what to do next.</p> <pre style="margin-left: 2em"><code><a href="http://www.gnu.org/software/wget/">wget</a> 'ftp://elsie.nci.nih.gov/pub/tz*.tar.gz' @@ -164,7 +164,7 @@ Timezone Converter</a> describes a progr <code>tz</code> source into iCalendar-compatible VTIMEZONE files. Vzic is freely available under the <a -href="http://www.gnu.org/copyleft/gpl.html"><acronym>GNU</acronym> +href="http://www.gnu.org/copyleft/gpl.html"><abbr>GNU</abbr> General Public License (<abbr title="General Public License">GPL</abbr>)</a>.</li> <li><a @@ -180,7 +180,7 @@ transition in the <code>tz</code> databa <li><a href="http://oss.software.ibm.com/icu/"><abbr title="International Components for Unicode">ICU</abbr></a> contains a C/C++ library for internationalization that -has a compiler from <samp>tz</samp> source +has a compiler from <code>tz</code> source into an <abbr>ICU</abbr>-specific format. <abbr>ICU</abbr> is freely available under a <abbr title="Berkeley Software Distribution">BSD</abbr>-style license.</li> @@ -198,18 +198,18 @@ It is freely available under a <abbr>BSD <h2>Other <code>tz</code> binary file readers</h2> <ul> <li>The <a -href="http://www.gnu.org/software/libc/"><acronym>GNU</acronym> C +href="http://www.gnu.org/software/libc/"><abbr>GNU</abbr> C Library</a> has an independent, thread-safe implementation of a <code>tz</code> binary file reader. This library is freely available under the <a href="http://www.gnu.org/copyleft/lesser.html"> -<acronym>GNU</acronym> Lesser General Public License +<abbr>GNU</abbr> Lesser General Public License (<abbr title="Lesser General Public License">LGPL</abbr>)</a>, -and is widely used in <acronym>GNU</acronym>/Linux systems.</li> +and is widely used in <abbr>GNU</abbr>/Linux systems.</li> <li><a href="http://www.bmsi.com/java/#TZ">ZoneInfo.java</a> is a <code>tz</code> binary file reader written in Java. -It is freely available under the <acronym>GNU</acronym> +It is freely available under the <abbr>GNU</abbr> <abbr>LGPL</abbr>.</li> <li><a href="http://s.keim.free.fr/tz/doc.html">Python time zones</a> is a <code>tz</code> binary file reader written in Python. @@ -218,7 +218,7 @@ It is freely available under a <abbr>BSD <h2>Other <code>tz</code>-based time zone conversion software</h2> <ul> <li><a href="http://java.sun.com/">Sun Java</a> releases since 1.4 -contain a copy of a subset of a recent <samp>tz</samp> database in a +contain a copy of a subset of a recent <code>tz</code> database in a Java-specific format.</li> <li><a href="http://www1.tip.nl/~t876506/AboutTimeZonesHC.html">HyperCard @@ -287,7 +287,7 @@ zone boundaries for multizone countries< boundaries between time zones within countries.</li> <li>Manifold.net's <a href="http://www.manifold.net/download/freemaps.html">Free Maps and -<acronym title="Geographic Information Systems">GIS</acronym> +<abbr title="Geographic Information Systems">GIS</abbr> Data</a> includes a Manifold-format map of world time zone boundaries distributed under the <abbr>GPL</abbr>.</li> @@ -413,8 +413,8 @@ Times</a> explains more abstruse astrono <abbr title="Barycentric Dynamic Time">TDB</abbr>.</li> <li>The <a href="http://www.iau.org/"><abbr title="International Astronomical Union">IAU</abbr></a>'s <a -href="http://www.iau-sofa.rl.ac.uk/"><acronym -title="Standards Of Fundamental Astronomy">SOFA</acronym></a> +href="http://www.iau-sofa.rl.ac.uk/"><abbr +title="Standards Of Fundamental Astronomy">SOFA</abbr></a> initiative publishes Fortran code for converting among time scales like <abbr title="International Atomic Time">TAI</abbr>, @@ -484,13 +484,21 @@ protocols.</li> Best of Dates, the Worst of Dates</a> covers many problems encountered by software developers when handling dates and time stamps.</li> <li><a -href="http://oss.software.ibm.com/cvs/icu/~checkout~/locale/docs/design/formatting/time_zone_localization.html">Time -Zone Localization</a> is a proposed mechanism for localizing time zone -labels and abbreviations; for example, one might use it to specify +href="http://ibm.com/software/globalization/icu"><abbr +title="International Components for Unicode">ICU</abbr></a> contains a +mechanism for localizing time zone +labels and abbreviations; for example, one can use it to specify Russian translations for "Eastern European Summer Time", "<abbr title="Eastern European Summer Time">EEST</abbr>", -and <code>Europe/Bucharest</code>.</li> -<li> Alphabetic time zone abbreviations should not be used as unique +and <code>Europe/Bucharest</code>. +This mechanism is part of the +<a href="http://unicode.org/cldr/">Unicode +<abbr title="Common Locale Data Repository">CLDR</abbr> Project</a>; +for example, the <a +href="http://www.unicode.org/cldr/data/diff/by_type/dates_timeZoneNames.html">By-Type +Chart for //ldml/dates/timeZoneNames/…</a> +shows values for time zone names in many locales.</li> +<li>Alphabetic time zone abbreviations should not be used as unique identifiers for <abbr>UTC</abbr> offsets as they are ambiguous in practice. For example, "<abbr>EST</abbr>" denotes 5 hours behind <abbr>UTC</abbr> in English-speaking North America, but it denotes 10 @@ -501,6 +509,21 @@ French-speaking North Americans prefer database contains English abbreviations for all time stamps but in many cases these are merely inventions of the database maintainers.</li> +<li>Numeric time zone abbreviations typically count hours east of +<abbr>UTC</abbr>, e.g., <code>+09</code> for Japan and +<code>-10</code> for Hawaii. However, the <abbr>POSIX</abbr> +<code>TZ</code> environment variable uses the opposite convention. For +example, one might use <code>TZ="JST-9"</code> and +<code>TZ="HST10"</code> for Japan and Hawaii, respectively. If the +<code>tz</code> database is available, it is usually better to use +settings like <code>TZ="Asia/Tokyo"</code> and +<code>TZ="Pacific/Honolulu"</code> instead, as this should avoid +confusion, handle old timestamps better, and insulate you better from +any future changes to the rules. One should never set +<abbr>POSIX</abbr> <code>TZ</code> to a value like +<code>"GMT-9"</code>, though, since this would falsely claim that +local time is nine hours ahead of <abbr>UTC</abbr> and the time zone +is called "<abbr>GMT</abbr>".</li> </ul> <h2>Related indexes</h2> <ul>