May 2004 - tz - lists.iana.org

proposed tz changes for Argentina, Mongolia, Mars, etc.
by Paul Eggert May 24, 2004

May 24, 2004

Here are proposed changes to the tz data. The most urgent items are this weekend's emergency law in Mendoza, Argentina, and a correction to the daylight-saving rules in Mongolia, as these changes affect current time stamps. Changes affecting current time stamps: * Mendoza, Argentina moved its clocks back this weekend due to an emergency law designed to save energy. (This is unusual, as normally clocks are moved forward to save energy, but apparently the province uses a lot of electricity in the morning.) Thanks to Mariano Absatz for this item. * Mongolia does observe daylight-saving time. Thanks to Ganbold Ts. for this item. Changes affecting historical time stamps: * Fixes for time stamps before 1901 in Singapore and Kuala Lumpur. Thanks to Mok Ly Yng for this item. * Cuiaba, Brazil used normal Brazilian daylight-saving rules in 1994/1995. (Sorry, I forgot to write down who told me this.) * The names of time zones in Alaska didn't change officially until November 30, 1983, which means Alaska was officially observing "Yukon Time" for most of November 1983. (Thanks to Arthur David Olson for this item.) Administrative change to how hard links are created: * Link the old name "Navajo" to America/Shiprock, not America/Denver. Commentary fixes only: * Quite a bit of commentary added for the hot topic of time and time zones on Mars. * A cross-reference to Cyprus in the `europe' file. * Calcutta is now officially called `Kolkata'. * The Date and Time Gateway has moved from bsdi.com (which no longer exists) to twiki.org. * Joseph Myers's page on time in Britain has moved from student.cusu.cam.ac.uk to www.srcf.ucam.org. * Add URLs pointing to ICU, Joda Time, and Sun Java 1.4. =================================================================== RCS file: RCS/southamerica,v retrieving revision 2003.5 retrieving revision 2003.5.0.1 diff -pu -r2003.5 -r2003.5.0.1 --- southamerica 2003/12/15 14:31:42 2003.5 +++ southamerica 2004/05/24 07:26:59 2003.5.0.1 @@ -141,6 +141,13 @@ Rule Arg 2000 only - Mar Sun>=1 0:00 0 - # This kind of things had always been done this way in Argentina. # We are still -03:00 all year round in all of the country. # +# From Mariano Absatz (2004-05-21): +# Today it was officially published that the Province of Mendoza is changing +# its timezone this winter... starting tomorrow night.... +# http://www.gobernac.mendoza.gov.ar/boletin/pdf/20040521-27158-normas.pdf +# From Paul Eggert (2004-05-24): +# It's Law No. 7,210. This change is due to a public power emergency, so for +# now we'll assume it's for this year only. # # From Paul Eggert (2002-01-22): # <a href="http://www.spicasc.net/horvera.html"> @@ -232,6 +239,8 @@ Zone America/Mendoza -4:35:16 - LMT 1894 -4:00 - WART 1992 Oct 18 -3:00 Arg AR%sT 1999 Oct 3 -4:00 Arg AR%sT 2000 Mar 3 + -3:00 - ART 2004 May 23 + -4:00 - WART 2004 Oct 17 -3:00 - ART # Aruba @@ -389,8 +398,8 @@ Rule Brazil 1992 only - Oct 25 0:00 1:0 Rule Brazil 1993 only - Jan 31 0:00 0 - # Decree <a href="http://pcdsh01.on.br/HV942.htm">942</a> (1993-09-28) # adopted by same states, plus AM. -# Decree <a href="http://pcdsh01.on.br/HV1252.htm">1,252</a> (1994-09-22) -# adopted by same states, minus AM and MT. +# Decree <a href="http://pcdsh01.on.br/HV1252.htm">1,252</a> (1994-09-22; +# web page corrected 2004-01-07) adopted by same states, minus AM. # Decree <a href="http://pcdsh01.on.br/HV1636.htm">1,636</a> (1995-09-14) # adopted by same states, plus MT and TO. # Decree <a href="http://pcdsh01.on.br/HV1674.htm">1,674</a> (1995-10-13) @@ -536,8 +545,6 @@ Zone America/Campo_Grande -3:38:28 - LMT # # Mato Grosso (MT) Zone America/Cuiaba -3:44:20 - LMT 1914 - -4:00 Brazil AM%sT 1994 Sep 22 - -4:00 - AMT 1995 Sep 14 -4:00 Brazil AM%sT 2003 Sep 24 -4:00 - AMT # =================================================================== RCS file: RCS/europe,v retrieving revision 2003.5 retrieving revision 2003.5.0.1 diff -pu -r2003.5 -r2003.5.0.1 --- europe 2003/12/15 14:31:42 2003.5 +++ europe 2004/05/24 07:26:59 2003.5.0.1 @@ -707,6 +707,9 @@ Zone Europe/Sofia 1:33:16 - LMT 1880 # Croatia # see Serbia and Montenegro +# Cyprus +# See the `asia' file. + # Czech Republic # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Czech 1945 only - Apr 8 2:00s 1:00 S =================================================================== RCS file: RCS/asia,v retrieving revision 2003.5 retrieving revision 2003.5.0.1 diff -pu -r2003.5 -r2003.5.0.1 --- asia 2003/12/15 14:31:42 2003.5 +++ asia 2004/05/24 07:26:59 2003.5.0.1 @@ -380,7 +380,7 @@ Zone Asia/Dili 8:22:20 - LMT 1912 # India # Zone NAME GMTOFF RULES FORMAT [UNTIL] -Zone Asia/Calcutta 5:53:28 - LMT 1880 +Zone Asia/Calcutta 5:53:28 - LMT 1880 # Kolkata 5:53:20 - HMT 1941 Oct # Howrah Mean Time? 6:30 - BURT 1942 May 15 # Burma Time 5:30 - IST 1942 Sep @@ -1012,17 +1012,13 @@ Rule NBorneo 1935 1941 - Sep 14 0:00 0:2 Rule NBorneo 1935 1941 - Dec 14 0:00 0 - # # peninsular Malaysia -# From Paul Eggert (2003-11-01): # The data here are taken from Mok Ly Yng (2003-10-30) # <http://www.math.nus.edu.sg/aslaksen/teaching/timezone.html>. -# Before 1901, Penang, Malacca and Singapore each had their own time zone; -# assume Kuala Lumpur used Malaccan time. # Zone NAME GMTOFF RULES FORMAT [UNTIL] -Zone Asia/Kuala_Lumpur 6:46:48 - LMT 1880 - 6:49:00 - MMT 1901 Jan 1 # Malacca Mean Time +Zone Asia/Kuala_Lumpur 6:46:46 - LMT 1901 Jan 1 6:55:25 - SMT 1905 Jun 1 # Singapore M.T. 7:00 - MALT 1933 Jan 1 # Malaya Time - 7:00 0:20 MALST 1936 + 7:00 0:20 MALST 1936 Jan 1 7:20 - MALT 1941 Sep 1 7:30 - MALT 1942 Feb 16 9:00 - JST 1945 Sep 12 @@ -1089,6 +1085,15 @@ Zone Indian/Maldives 4:54:00 - LMT 1880 # # [The province of Selenge is omitted from the above lists.] +# From Ganbold Ts., Ulaanbaatar <ganbold(a)micom.mng.net> (2004-04-17): +# Daylight saving occurs at 02:00 local time last Saturday of March. +# It will change back to normal at 02:00 local time last Saturday of +# September.... As I remember this rule was changed in 2001. +# +# From Paul Eggert (2004-04-17): +# For now, assume Rives McDow's informant got confused about Friday vs +# Saturday, and that his 2001 dates should have 1 added to them. + # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Mongol 1983 1984 - Apr 1 0:00 1:00 S Rule Mongol 1983 only - Oct 1 0:00 0 - @@ -1098,8 +1103,9 @@ Rule Mongol 1983 only - Oct 1 0:00 0 - Rule Mongol 1985 1998 - Mar lastSun 2:00s 1:00 S Rule Mongol 1984 1998 - Sep lastSun 2:00s 0 - # IATA SSIM (1999-09) says Mongolia no longer observes DST. -Rule Mongol 2001 only - Apr 27 2:00s 1:00 S -Rule Mongol 2001 only - Sep 28 2:00s 0 - +Rule Mongol 2001 only - Apr lastSat 2:00 1:00 S +Rule Mongol 2001 max - Sep lastSat 2:00 0 - +Rule Mongol 2002 max - Mar lastSat 2:00 1:00 S # Zone NAME GMTOFF RULES FORMAT [UNTIL] # Hovd, a.k.a. Chovd, Dund-Us, Dzhargalant, Khovd, Jirgalanta @@ -1309,10 +1315,10 @@ Zone Asia/Riyadh 3:06:52 - LMT 1950 # The data here are taken from Mok Ly Yng (2003-10-30) # <http://www.math.nus.edu.sg/aslaksen/teaching/timezone.html>. # Zone NAME GMTOFF RULES FORMAT [UNTIL] -Zone Asia/Singapore 6:55:25 - LMT 1880 +Zone Asia/Singapore 6:55:25 - LMT 1901 Jan 1 6:55:25 - SMT 1905 Jun 1 # Singapore M.T. 7:00 - MALT 1933 Jan 1 # Malaya Time - 7:00 0:20 MALST 1936 + 7:00 0:20 MALST 1936 Jan 1 7:20 - MALT 1941 Sep 1 7:30 - MALT 1942 Feb 16 9:00 - JST 1945 Sep 12 =================================================================== RCS file: RCS/tz-link.htm,v retrieving revision 2003.5 retrieving revision 2003.5.0.1 diff -pu -r2003.5 -r2003.5.0.1 --- tz-link.htm 2003/12/15 14:31:42 2003.5 +++ tz-link.htm 2004/05/24 07:26:59 2003.5.0.1 @@ -9,7 +9,7 @@ <meta http-equiv="Content-type" content='text/html; charset="US-ASCII"' /> <meta name="DC.Creator" content="Eggert, Paul" /> <meta name="DC.Contributor" content="Olson, Arthur David" /> -<meta name="DC.Date" content="2003-09-21" /> +<meta name="DC.Date" content="2004-05-24" /> <meta name="DC.Description" content="Sources of information about time zones and daylight saving time" /> <meta name="DC.Identifier" content="http://www.twinsun.com/tz/tz-link.htm" /> @@ -99,8 +99,8 @@ Here are some recent links that may be o </p> <h2>Web pages using recent versions of the <code>tz</code> database</h2> <ul> -<li><a href="http://www.bsdi.com/date/">Date and Time Gateway</a> is a -text-based point-and-click interface to tables of current time +<li><a href="http://twiki.org/cgi-bin/xtra/tzdate">Date and Time Gateway</a> +is a text-based point-and-click interface to tables of current time throughout the world.</li> <li>Fancier web interfaces, roughly in ascending order of complexity, include: <ul> @@ -157,6 +157,15 @@ href="http://www.perl.com/language/misc/ License</a>. DateTime::TimeZone also contains a script <code>tests_from_zdump</code> that generates test cases for each clock transition in the <code>tz</code> database.</li> +<li><a href="http://oss.software.ibm.com/icu/">International Components for +Unicode (ICU)</a> contains a C/C++ library for internationalization that +has a compiler from <samp>tz</samp> source into an ICU-specific format. +ICU is freely available under a BSD-style license.</li> +<li><a href="http://joda-time.sourceforge.net/">Joda Time - Java date +and time API</a> contains a class +<code>org.joda.time.tz.ZoneInfoCompiler</code> that compiles +<code>tz</code> source into a Joda-specific binary format. Joda Time +is freely available under a BSD-style license.</li> </ul> <h2>Other <code>tz</code> binary file readers</h2> <ul> @@ -177,6 +186,9 @@ under a BSD-style license.</li> </ul> <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 recent <samp>tz</samp> database in a Java-specific +format.</li> <li><a href="http://www1.tip.nl/~t876506/AboutTimeZonesHC.html">HyperCard time zones calculator</a> is a HyperCard stack.</li> @@ -330,7 +342,7 @@ is Singapore in the "Wrong" Time Zone?</ history of legal time in Singapore and Malaysia.</dd> <dt>United Kingdom</dt> <dd><a -href="http://student.cusu.cam.ac.uk/~jsm28/british-time/">History of +href="http://www.srcf.ucam.org/~jsm28/british-time/">History of legal time in Britain</a> discusses in detail the country with perhaps the best-documented history of clock adjustments. The National Physical Laboratory also maintains an <a @@ -362,6 +374,11 @@ among time scales like TAI, TDB, TT and Space Flight - Reference Systems - Time Conventions</a> briefly explains interplanetary space flight timekeeping.</li> <li><a +href="http://www.giss.nasa.gov/tools/mars24/help/notes.html">Technical +Notes on Mars Solar Time as Adopted by the Mars24 Sunclock</a> briefly +describes Mars Coordinated Time (MTC) and the diverse local time +scales used by each landed mission on Mars.</li> +<li><a href="http://hpiers.obspm.fr/eop-pc/products/bulletins/bulletins.html">Bulletins maintained by the IERS EOP (PC)</a> contains official publications of the Earth Orientation Parameters Product Center of the =================================================================== RCS file: RCS/northamerica,v retrieving revision 2003.5 retrieving revision 2003.5.0.1 diff -pu -r2003.5 -r2003.5.0.1 --- northamerica 2003/12/15 14:36:18 2003.5 +++ northamerica 2004/05/24 07:26:59 2003.5.0.1 @@ -193,10 +193,6 @@ Rule US 1987 max - Apr Sun>=1 2:00 1:00 # Samoa standard time # The law doesn't give abbreviations. # -# From Paul Eggert (1995-12-19): -# Shanks uses 1983-10-30, not 1983-11-30, for the 1983 transitions. -# Go with Shanks. -# # From Paul Eggert (2000-01-08), following a heads-up from Rives McDow: # Public law 106-564 (2000-12-23) introduced the abbreviation # "Chamorro Standard Time" for time in Guam and the Northern Marianas. @@ -323,13 +319,14 @@ Zone America/Juneau 15:02:19 - LMT 1867 -8:00 US P%sT 1946 -8:00 - PST 1969 -8:00 US P%sT 1983 Oct 30 2:00 + -9:00 US Y%sT 1983 Nov 30 -9:00 US AK%sT Zone America/Yakutat 14:41:05 - LMT 1867 Oct 18 -9:18:55 - LMT 1900 Aug 20 12:00 -9:00 - YST 1942 -9:00 US Y%sT 1946 -9:00 - YST 1969 - -9:00 US Y%sT 1983 Oct 30 2:00 + -9:00 US Y%sT 1983 Nov 30 -9:00 US AK%sT Zone America/Anchorage 14:00:24 - LMT 1867 Oct 18 -9:59:36 - LMT 1900 Aug 20 12:00 @@ -338,6 +335,7 @@ Zone America/Anchorage 14:00:24 - LMT 1 -10:00 - CAT 1967 Apr -10:00 - AHST 1969 -10:00 US AH%sT 1983 Oct 30 2:00 + -9:00 US Y%sT 1983 Nov 30 -9:00 US AK%sT Zone America/Nome 12:58:21 - LMT 1867 Oct 18 -11:01:38 - LMT 1900 Aug 20 12:00 @@ -346,6 +344,7 @@ Zone America/Nome 12:58:21 - LMT 1867 O -11:00 - NST 1967 Apr -11:00 - BST 1969 -11:00 US B%sT 1983 Oct 30 2:00 + -9:00 US Y%sT 1983 Nov 30 -9:00 US AK%sT Zone America/Adak 12:13:21 - LMT 1867 Oct 18 -11:46:38 - LMT 1900 Aug 20 12:00 @@ -354,6 +353,7 @@ Zone America/Adak 12:13:21 - LMT 1867 O -11:00 - NST 1967 Apr -11:00 - BST 1969 -11:00 US B%sT 1983 Oct 30 2:00 + -10:00 US AH%sT 1983 Nov 30 -10:00 US HA%sT # Shanks writes that part of southwest Alaska (e.g. Aniak) # switched from -11:00 to -10:00 on 1968-09-22 at 02:00, =================================================================== RCS file: RCS/backward,v retrieving revision 2003.4 retrieving revision 2003.4.0.1 diff -pu -r2003.4 -r2003.4.0.1 --- backward 2003/10/06 13:32:20 2003.4 +++ backward 2004/05/24 07:26:59 2003.4.0.1 @@ -65,7 +65,7 @@ Link Africa/Tripoli Libya Link America/Tijuana Mexico/BajaNorte Link America/Mazatlan Mexico/BajaSur Link America/Mexico_City Mexico/General -Link America/Denver Navajo +Link America/Shiprock Navajo Link Pacific/Auckland NZ Link Pacific/Chatham NZ-CHAT Link Pacific/Pago_Pago Pacific/Samoa =================================================================== RCS file: RCS/Theory,v retrieving revision 2003.5 retrieving revision 2003.5.0.1 diff -pu -r2003.5 -r2003.5.0.1 --- Theory 2003/12/15 14:36:34 2003.5 +++ Theory 2004/05/24 07:26:59 2003.5.0.1 @@ -7,6 +7,7 @@ Names of time zone regions Time zone abbreviations Calendrical issues + Time and time zones on Mars ----- Time and date functions ----- @@ -504,3 +505,48 @@ convert to the Gregorian calendar until Source: H. Grotefend, _Taschenbuch der Zeitrechnung des deutschen Mittelalters und der Neuzeit_, herausgegeben von Dr. O. Grotefend (Hannover: Hahnsche Buchhandlung, 1941), pp. 26-28. + + +----- Time and time zones on Mars ----- + +Some people have adjusted their work schedules to fit Mars time. +Dozens of special Mars watches were built for Jet Propulsion +Laboratory workers who kept Mars time during the Mars Exploration +Rovers mission (2004). These timepieces look like normal Seikos and +Citizens but use Mars seconds rather than terrestrial seconds. + +A Mars solar day is called a "sol" and has a mean period equal to +about 24 hours 39 minutes 35.244 seconds in terrestrial time. It is +divided into a conventional 24-hour clock, so each Mars second equals +about 1.02749125 terrestrial seconds. + +The prime meridian of Mars goes through the center of the crater +Airy-0, named in honor of the British astronomer who built the +Greenwich telescope that defines Earth's prime meridian. Mean solar +time on the Mars prime meridian is called Mars Coordinated Time (MTC). + +Each landed mission on Mars has adopted a different reference for +solar time keeping, so there is no real standard for Mars time zones. +For example, the Mars Exploration Rover project (2004) defined two +time zones "Local Solar Time A" and "Local Solar Time B" for its two +missions, each zone designed so that its time equals local true solar +time at approximately the middle of the nominal mission. Such a "time +zone" is not particularly suited for any application other than the +mission itself. + +Many calendars have been proposed for Mars, but none have achieved +wide acceptance. Astronomers often use Mars Sol Date (MSD) which is a +sequential count of Mars solar days elapsed since about 1873-12-29 +12:00 GMT. + +The tz database does not currently support Mars time, but it is +documented here in the hopes that support will be added eventually. + +Sources: + +Michael Allison and Robert Schmunk, +"Technical Notes on Mars Solar Time as Adopted by the Mars24 Sunclock" +<http://www.giss.nasa.gov/tools/mars24/help/notes.html> (2004-03-15). + +Jia-Rui Chong, "Workdays Fit for a Martian", Los Angeles Times +(2004-01-14), pp A1, A20-A21.

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Argentina - Mendoza: Changes
by Mariano Absatz May 21, 2004

May 21, 2004

Hi, well, today it was officially published that the Province of Mendoza is changing its timezone this winter... starting tomorrow night. I'm quite in a hurry, but: At midnight Saturday May 22nd, the clocks will be pulled back one hour (from UTC-03:00 to UTC-04:00). At midnight Saturday October 16th, the clocks will get back to UTC-03:00. The Official data is at http://www.gobernac.mendoza.gov.ar/boletin/pdf/20040521-27158-normas.pdf (in Spanish). Regards. -- Mariano Absatz - El Baby mailto:baby@baby.com.ar http://www.baby.com.ar/ PGP KEYS: http://www.baby.com.ar/datos/personales.html#claves_pgp |\ _ _\\/'> Powered by Pegasus Mail /|__) http://www.pmail.com ) )\ ----------------------------------------------------------- Windows, another fine product from the folks who gave us EDLIN.

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possible changes in Argentina (southamerica)
by Mariano Absatz May 19, 2004

May 19, 2004

Hi, Apparently, the Province of Mendoza, in Argentina's Mid-West, is about to change it's timezone to UTC-04:00 Most of Argentina lies 'geographically' in that tz, but at some point in time, after having implemented UTC-03:00 for the summer, the country 'just stayed there'... what's more, a few years ago, for some time, it used a summer tz of UTC-02:00. As Mendoza is one of the Provinces in the Western border, it is most affected for using a 'more Eastern' tz, and this is especially bad in the (Southern) winter. As there's an Energy crisis in Argentina, Mendoza is trying to 'wake up an hour later'. It remains to be seen if the Province of Mendoza effectively legislates this and what the other Provinces do (especially, the other Provinces in the West). Newspaper info (in Spanish): http://www.lanacion.com.ar/04/05/11/de_600178.asp http://www.clarin.com/diario/2004/05/15/elpais/p-00401.htm http://www1.cronica.com.ar/article/articleview/1084567955/1/20/ http://www.losandes.com.ar/2004/0505/editorial/nota186060_1.htm http://www.losandes.com.ar/2004/0512/economia/nota187333_1.htm I'll keep the list posted as this develops. Regards. -- Mariano Absatz - El Baby mailto:baby@baby.com.ar http://www.baby.com.ar/ PGP KEYS: http://www.baby.com.ar/datos/personales.html#claves_pgp |\ _ _\\/'> Powered by Pegasus Mail /|__) http://www.pmail.com ) )\

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Time zones from Windows XP
by Ruby Ballen May 18, 2004

May 18, 2004

I am new in this mailing list so, please, forgive me if this has been asked before. I'm trying to map the list of time zones that Windows XP includes, to the correct binary files in tz Database, but I am missing some of them. I just could not find which one to use or if it is supported at all. Here is the list: (GMT - 12:00) International Date Line West (GMT - 06:00) Central America (GMT - 03:00) Brasilia (GMT - 02:00) Mid-Atlantic (GMT + 01:00) West Central Africa (GMT + 06:00) Sri Jayawardenepura (GMT + 13:00) Nuku’alofa Also, is there any site where I can find documentation about this library? Thanks a lot for your help. RBallen

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tzdata 2003e: imperfections
by Oscar van Vlijmen May 18, 2004

May 18, 2004

I found a couple of small imperfections in the tzdata files. asia file: Cyprus is now (May 01, 2004) part of the European Union. In spite of the interesting remarks for Cyprus in the tz data file, the Cyprus entry should be in the europe file. antarctica file: New Zealand: Rules are given, but no Zone information, so no actual time information. All files: GMT is obsolete. UTC should be used. Nearly all files, lots of entries: In some cases DST is no longer observed, but the Zone lines still mention a DST Rule. One example from the asia file (some information omitted by me): # Korea (North and South) ... # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule ROK 1960 only - May 15 0:00 1:00 D Rule ROK 1960 only - Sep 13 0:00 0 S Rule ROK 1987 1988 - May Sun<=14 0:00 1:00 D Rule ROK 1987 1988 - Oct Sun<=14 0:00 0 S # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Asia/Seoul 8:27:52 - LMT 1890 8:30 - KST 1904 Dec 9:00 - KST 1928 8:30 - KST 1932 9:00 - KST 1954 Mar 21 8:00 ROK K%sT 1961 Aug 10 8:30 - KST 1968 Oct 9:00 ROK K%sT ... Since South Korea no longer observes DST, it would be better for the consistency of the database if the last line was changed into: 9:00 ROK K%sT 1988 Oct and an extra line was added, like: 9:00 - KST The software will give the correct time for e.g. this moment I guess, because no Rule line can be found, valid for May 2004. So, changing the database files for this could get a low priority, but it is still an imperfection! Oscar van Vlijmen 2004-05-17

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RE: tzdata 2003e: imperfections (DST rules)
by Olson, Arthur David (NIH/NCI) May 17, 2004

May 17, 2004

> If I am interpreting the documentation correctly, then the last Zone line says that there is a Rule "ROK" in effect, but for dates after Sunday October 09, 1988 no Rule can be found. The last Rule line says that on Sunday October 09, 1988 you should transition out of DST, and that's what the software does. After that, there aren't any transitions specified by Rules, so the software doesn't do anything else. This really is what's supposed to happen; there's no need for a change here. --ado

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Re: tzdata 2003e: imperfections (DST rules)
by Oscar van Vlijmen May 17, 2004

May 17, 2004

> From: "Olson, Arthur David (NIH/NCI)" > Remember that the Rules tell when DST transitions happen; in the above case, > the Rule that's valid is one that specifies the last transition before May > 2004, which is assumed to be in effect in perpetuity. Excerpts from the zic.8 documentation file: " A rule line has the form Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S .... TO Gives the final year in which the rule applies. In addition to minimum and maximum (as above), the word only (or an abbreviation) may be used to repeat the value of the FROM field. .... The fields that make up a zone line are: Zone NAME GMTOFF RULES/SAVE FORMAT [UNTIL] .... UNTIL The time at which the UTC offset or the rule(s) change for a location. It is specified as a year, a month, a ..... " The Rule and Zone (continuation) lines from the example are: Rule ROK 1987 1988 - Oct Sun<=14 0:00 0 S Zone... 9:00 ROK K%sT If I am interpreting the documentation correctly, then the last Zone line says that there is a Rule "ROK" in effect, but for dates after Sunday October 09, 1988 no Rule can be found. The DST rules were changed, so, strictly speaking, and according to the documentation, there should be a new Zone line. For users of the TZ software there is no problem I guess, but developers who can only use the database files, encounter minor problems interpreting the database. Oscar van Vlijmen 2004-05-17

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RE: tzdata 2003e: imperfections
by Olson, Arthur David (NIH/NCI) May 17, 2004

May 17, 2004

> 9:00 ROK K%sT > ... > > Since South Korea no longer observes DST, it would be better for the consistency of the database if the last line was changed into: > 9:00 ROK K%sT 1988 Oct > and an extra line was added, like: > 9:00 - KST Generally speaking, we want to have the last line of a Zone refer to a Rule line. This is particularly important in cases where a country has multiple time zones. If the country decides in the future to change the way DST is handled (for example, decides to start observing DST again), we can make things right by changing one Rule rather than by changing multiple Zones. > The software will give the correct time for e.g. this moment I guess, because no Rule line can be found, valid for May 2004. > So, changing the database files for this could get a low priority, but it is still an imperfection! Remember that the Rules tell when DST transitions happen; in the above case, the Rule that's valid is one that specifies the last transition before May 2004, which is assumed to be in effect in perpetuity. --ado

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