proposed tz changes for Argentina, Mongolia, Mars, etc.

Mon May 24 07:49:37 UTC 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 at 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.

