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Egypt plan to cancell DST during Ramadan and then to resume DST again.
by Alexander Krivenyshev July 20, 2010

July 20, 2010

According to News from Egypt - Al-Masry Al-Youm Egypt's cabinet has decided that Daylight Saving Time will not be used in Egypt during Ramadan. arabic translation: "Clocks to go back during Ramadan--and then forward again " http://www.almasryalyoum.com/en/news/clocks-go-back-during-ramadan-and-then- forward-again or http://www.worldtimezone.com/dst_news/dst_news_egypt02.html Alexander Krivenyshev, http://www.worldtimezone.com

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proposed time zone package changes
by Arthur David Olson July 17, 2010

July 17, 2010

Below find proposed changes to the time zone package. The executive summary: * australasia Change Pacific/Truk to Pacific/Chuuk (with corresponding time zone abbreviation change) and change Pacific/Ponape to Pacific/Pohnpei (with thanks to Clint Adams). * backward add Pacific/Truk and Pacific/Ponape links and adjust Pacific/Yap link. * europe Change Finland transition times in 1981 and 1982 (with thanks to Janne Snabb). * leapseconds Update comments with latest IERS leap second bulletin. * northamerica Correct instant of 2010 move between time zones in Bahia de Banderas. Add comments from Mark Brader on DST in Windsor. Add comments on Canadian DST in 1930 from the Journal of the Royal Astronomical Society of Canada. * tz-link.htm Add link to http://code.google.com/p/tzdata/ (from Rich Tibbett). * zone.tab Change Pacific/Truk to Pacific/Chuuk and change Pacific/Ponape to Pacific/Pohnpei (More research is needed on when Windsor, Ontario started using DST before adding a Windsor time zone.) If no problems are found, these changes will appear on the ftp site on 2010-07-26. --ado diff -c old/australasia new/australasia *** old/australasia Mon May 10 09:07:27 2010 --- new/australasia Sat Jul 17 09:14:35 2010 *************** *** 1,5 **** # <pre> ! # @(#)australasia 8.17 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. --- 1,5 ---- # <pre> ! # @(#)australasia 8.18 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. *************** *** 346,355 **** # Micronesia # Zone NAME GMTOFF RULES FORMAT [UNTIL] ! Zone Pacific/Truk 10:07:08 - LMT 1901 ! 10:00 - TRUT # Truk Time ! Zone Pacific/Ponape 10:32:52 - LMT 1901 # Kolonia ! 11:00 - PONT # Ponape Time Zone Pacific/Kosrae 10:51:56 - LMT 1901 11:00 - KOST 1969 Oct # Kosrae Time 12:00 - KOST 1999 --- 346,355 ---- # Micronesia # Zone NAME GMTOFF RULES FORMAT [UNTIL] ! Zone Pacific/Chuuk 10:07:08 - LMT 1901 ! 10:00 - CHUT # Chuuk Time ! Zone Pacific/Pohnpei 10:32:52 - LMT 1901 # Kolonia ! 11:00 - PONT # Pohnpei Time Zone Pacific/Kosrae 10:51:56 - LMT 1901 11:00 - KOST 1969 Oct # Kosrae Time 12:00 - KOST 1999 diff -c old/backward new/backward *** old/backward Mon May 10 09:07:27 2010 --- new/backward Sat Jul 17 09:14:35 2010 *************** *** 1,5 **** # <pre> ! # @(#)backward 8.8 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. --- 1,5 ---- # <pre> ! # @(#)backward 8.9 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. *************** *** 90,96 **** Link America/Denver Navajo Link Asia/Shanghai PRC Link Pacific/Pago_Pago Pacific/Samoa ! Link Pacific/Truk Pacific/Yap Link Europe/Warsaw Poland Link Europe/Lisbon Portugal Link Asia/Taipei ROC --- 90,98 ---- Link America/Denver Navajo Link Asia/Shanghai PRC Link Pacific/Pago_Pago Pacific/Samoa ! Link Pacific/Chuuk Pacific/Yap ! Link Pacific/Chuuk Pacific/Truk ! Link Pacific/Pohnpei Pacific/Ponape Link Europe/Warsaw Poland Link Europe/Lisbon Portugal Link Asia/Taipei ROC diff -c old/europe new/europe *** old/europe Mon May 10 09:07:27 2010 --- new/europe Sat Jul 17 09:05:51 2010 *************** *** 1,5 **** # <pre> ! # @(#)europe 8.26 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. --- 1,5 ---- # <pre> ! # @(#)europe 8.27 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. *************** *** 1013,1034 **** 2:00 EU EE%sT # Finland ! # # From Hannu Strang (1994-09-25 06:03:37 UTC): # Well, here in Helsinki we're just changing from summer time to regular one, # and it's supposed to change at 4am... # ! # From Paul Eggert (2006-03-22): ! # Shanks & Pottenger say Finland has switched at 02:00 standard time ! # since 1981. Go with Strang instead. # # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Finland 1942 only - Apr 3 0:00 1:00 S Rule Finland 1942 only - Oct 3 0:00 0 - # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Europe/Helsinki 1:39:52 - LMT 1878 May 31 1:39:52 - HMT 1921 May # Helsinki Mean Time ! 2:00 Finland EE%sT 1981 Mar 29 2:00 2:00 EU EE%sT # Aaland Is --- 1013,1059 ---- 2:00 EU EE%sT # Finland ! # From Hannu Strang (1994-09-25 06:03:37 UTC): # Well, here in Helsinki we're just changing from summer time to regular one, # and it's supposed to change at 4am... + + # From Janne Snabb (2010-0715): # ! # I noticed that the Finland data is not accurate for years 1981 and 1982. ! # During these two first trial years the DST adjustment was made one hour ! # earlier than in forthcoming years. Starting 1983 the adjustment was made ! # according to the central European standards. # + # This is documented in Heikki Oja: Aikakirja 2007, published by The Almanac + # Office of University of Helsinki, ISBN 952-10-3221-9, available online (in + # Finnish) at + # + # <a href="http://almanakka.helsinki.fi/aikakirja/Aikakirja2007kokonaan.pdf"> + # http://almanakka.helsinki.fi/aikakirja/Aikakirja2007kokonaan.pdf + # </a> + # + # Page 105 (56 in PDF version) has a handy table of all past daylight savings + # transitions. It is easy enough to interpret without Finnish skills. + # + # This is also confirmed by Finnish Broadcasting Company's archive at: + # + # <a href="http://www.yle.fi/elavaarkisto/?s=s&g=1&ag=5&t=&a=3401"> + # http://www.yle.fi/elavaarkisto/?s=s&g=1&ag=5&t=&a=3401 + # </a> + # + # The news clip from 1981 says that "the time between 2 and 3 o'clock does not + # exist tonight." + # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Finland 1942 only - Apr 3 0:00 1:00 S Rule Finland 1942 only - Oct 3 0:00 0 - + Rule Finland 1981 1982 - Mar lastSun 2:00 1:00 S + Rule Finland 1981 1982 - Sep lastSun 3:00 0 - # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Europe/Helsinki 1:39:52 - LMT 1878 May 31 1:39:52 - HMT 1921 May # Helsinki Mean Time ! 2:00 Finland EE%sT 1983 2:00 EU EE%sT # Aaland Is diff -c old/leapseconds new/leapseconds *** old/leapseconds Mon May 10 09:07:28 2010 --- new/leapseconds Sat Jul 17 08:51:09 2010 *************** *** 1,5 **** # <pre> ! # @(#)leapseconds 8.9 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. --- 1,5 ---- # <pre> ! # @(#)leapseconds 8.10 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. *************** *** 60,68 **** # FAX : 33 (0) 1 40 51 22 91 # Internet : services.iers(a)obspm.fr # ! # Paris, 4 July 2009 # ! # Bulletin C 38 # # To authorities responsible # for the measurement and --- 60,68 ---- # FAX : 33 (0) 1 40 51 22 91 # Internet : services.iers(a)obspm.fr # ! # Paris, 14 July 2010 # ! # Bulletin C 40 # # To authorities responsible # for the measurement and *************** *** 70,78 **** # # INFORMATION ON UTC - TAI # ! # NO positive leap second will be introduced at the end of December 2009. # The difference between Coordinated Universal Time UTC and the ! # International Atomic Time TAI is : # # from 2009 January 1, 0h UTC, until further notice : UTC-TAI = -34 s # --- 70,78 ---- # # INFORMATION ON UTC - TAI # ! # NO positive leap second will be introduced at the end of December 2010. # The difference between Coordinated Universal Time UTC and the ! # International Atomic Time TAI is : # # from 2009 January 1, 0h UTC, until further notice : UTC-TAI = -34 s # *************** *** 82,87 **** # will be no time step at the next possible date. # # Daniel GAMBIS ! # Director # Earth Orientation Center of IERS # Observatoire de Paris, France --- 82,87 ---- # will be no time step at the next possible date. # # Daniel GAMBIS ! # Director # Earth Orientation Center of IERS # Observatoire de Paris, France diff -c old/northamerica new/northamerica *** old/northamerica Mon May 10 09:07:27 2010 --- new/northamerica Sat Jul 17 10:07:20 2010 *************** *** 1,5 **** # <pre> ! # @(#)northamerica 8.31 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. --- 1,5 ---- # <pre> ! # @(#)northamerica 8.34 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. *************** *** 1324,1329 **** --- 1324,1406 ---- # entry since our cutoff date of 1970, so we can move # America/Coral_Harbour to the 'backward' file. + # From Mark Brader (2010-03-06): + # + # Currently the database has: + # + # # Ontario + # + # # From Paul Eggert (2006-07-09): + # # Shanks & Pottenger write that since 1970 most of Ontario has been like + # # Toronto. + # # Thunder Bay skipped DST in 1973. + # # Many smaller locales did not observe peacetime DST until 1974; + # # Nipigon (EST) and Rainy River (CST) are the largest that we know of. + # + # In the (Toronto) Globe and Mail for Saturday, 1955-09-24, in the bottom + # right corner of page 1, it says that Toronto will return to standard + # time at 2 am Sunday morning (which agrees with the database), and that: + # + # The one-hour setback will go into effect throughout most of Ontario, + # except in areas like Windsor which remains on standard time all year. + # + # Windsor is, of course, a lot larger than Nipigon. + # + # I only came across this incidentally. I don't know if Windsor began + # observing DST when Detroit did, or in 1974, or on some other date. + # + # By the way, the article continues by noting that: + # + # Some cities in the United States have pushed the deadline back + # three weeks and will change over from daylight saving in October. + + # From Arthur David Olson (2010-07-17): + # + # "Standard Time and Time Zones in Canada" appeared in + # The Journal of The Royal Astronomical Society of Canada, + # volume 26, number 2 (February 1932) and, as of 2010-07-17, + # was available at + # <a href="http://adsabs.harvard.edu/full/1932JRASC..26...49S"> + # http://adsabs.harvard.edu/full/1932JRASC..26...49S + # </a> + # + # It includes the text below (starting on page 57): + # + # A list of the places in Canada using daylight saving time would + # require yearly revision. From information kindly furnished by + # the provincial governments and by the postmasters in many cities + # and towns, it is found that the following places used daylight sav- + # ing in 1930. The information for the province of Quebec is definite, + # for the other provinces only approximate: + # + # Province Daylight saving time used + # Prince Edward Island Not used. + # Nova Scotia In Halifax only. + # New Brunswick In St. John only. + # Quebec In the following places: + # Montreal Lachine + # Quebec Mont-Royal + # Levis Iberville + # St. Lambert Cap de la Madeleine + # Verdun Loretteville + # Westmount Richmond + # Outremont St. Jerome + # Longueuil Greenfield Park + # Arvida Waterloo + # Chambly-Canton Beaulieu + # Melbourne La Tuque + # St. Theophile Buckingham + # Ontario Used generally in the cities and towns along + # the southerly part of the province. Not + # used in the northwesterlhy part. + # Manitoba Not used. + # Saskatchewan In Regina only. + # Alberta Not used. + # British Columbia Not used. + # + # With some exceptions, the use of daylight saving may be said to be limited + # to those cities and towns lying between Quebec city and Windsor, Ont. + # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Toronto 1919 only - Mar 30 23:30 1:00 D Rule Toronto 1919 only - Oct 26 0:00 0 S *************** *** 2147,2153 **** -6:00 - CST 1942 Apr 24 -7:00 - MST 1949 Jan 14 -8:00 - PST 1970 ! -7:00 Mexico M%sT 2010 Apr 4 -6:00 Mexico C%sT # Baja California (near US border) --- 2224,2230 ---- -6:00 - CST 1942 Apr 24 -7:00 - MST 1949 Jan 14 -8:00 - PST 1970 ! -7:00 Mexico M%sT 2010 Apr 4 2:00 -6:00 Mexico C%sT # Baja California (near US border) diff -c old/tz-link.htm new/tz-link.htm *** old/tz-link.htm Mon May 10 09:07:28 2010 --- new/tz-link.htm Sat Jul 17 08:56:39 2010 *************** *** 18,24 **** <body> <h1>Sources for Time Zone and Daylight Saving Time Data</h1> <address> ! @(#)tz-link.htm 8.27 </address> <p> This file is in the public domain, so clarified as of --- 18,24 ---- <body> <h1>Sources for Time Zone and Daylight Saving Time Data</h1> <address> ! @(#)tz-link.htm 8.28 </address> <p> This file is in the public domain, so clarified as of *************** *** 351,356 **** --- 351,367 ---- → Tzid table</a> maintained by the <abbr title="Common Locale Data Repository">CLDR</abbr> data mentioned below.</li> + <li> + <a href="http://code.google.com/p/tzdata/"> + http://code.google.com/p/tzdata/ + </a> + provides programming-language-specific representations of timezone + data. Currently this includes XML, PHP, Ruby, Javascript, JSON and CSV + formatted data. The repository is updated as soon as the FTP + distribution is updated. All data can be downloaded as a zip and/or it + can be obtained/synced via anonymous SVN. Data is made available under + the MIT license. (From Rich Tibbett.) + </li> </ul> <h2>Maps</h2> <ul> diff -c old/zone.tab new/zone.tab *** old/zone.tab Mon May 10 09:07:28 2010 --- new/zone.tab Sat Jul 17 09:14:35 2010 *************** *** 1,5 **** # <pre> ! # @(#)zone.tab 8.36 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. # --- 1,5 ---- # <pre> ! # @(#)zone.tab 8.37 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. # *************** *** 177,184 **** FI +6010+02458 Europe/Helsinki FJ -1808+17825 Pacific/Fiji FK -5142-05751 Atlantic/Stanley ! FM +0725+15147 Pacific/Truk Truk (Chuuk) and Yap ! FM +0658+15813 Pacific/Ponape Ponape (Pohnpei) FM +0519+16259 Pacific/Kosrae Kosrae FO +6201-00646 Atlantic/Faroe FR +4852+00220 Europe/Paris --- 177,184 ---- FI +6010+02458 Europe/Helsinki FJ -1808+17825 Pacific/Fiji FK -5142-05751 Atlantic/Stanley ! FM +0725+15147 Pacific/Chuuk Chuuk (Truk) and Yap ! FM +0658+15813 Pacific/Pohnpei Pohnpei (Ponape) FM +0519+16259 Pacific/Kosrae Kosrae FO +6201-00646 Atlantic/Faroe FR +4852+00220 Europe/Paris

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Bulletin C number 40
by IERS EOP Product Center July 16, 2010

July 16, 2010

INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE SERVICE DE LA ROTATION TERRESTRE OBSERVATOIRE DE PARIS 61, Av. de l'Observatoire 75014 PARIS (France) Tel. : 33 (0) 1 40 51 22 26 FAX : 33 (0) 1 40 51 22 91 Internet : services.iers(a)obspm.fr Paris, 14 July 2010 Bulletin C 40 To authorities responsible for the measurement and distribution of time INFORMATION ON UTC - TAI NO positive leap second will be introduced at the end of December 2010. The difference between Coordinated Universal Time UTC and the International Atomic Time TAI is : from 2009 January 1, 0h UTC, until further notice : UTC-TAI = -34 s Leap seconds can be introduced in UTC at the end of the months of December or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every six months, either to announce a time step in UTC, or to confirm that there will be no time step at the next possible date. Daniel GAMBIS Director Earth Orientation Center of IERS Observatoire de Paris, France __________________________________________

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FW: Europe/Finland DST correction for years 1981 and 1982
by Olson, Arthur David (NIH/NCI) [E] July 15, 2010

July 15, 2010

I'm forwarding this message from Janne Snabb, who is not on the time zone mailing list. Those of you who are on the list, please direct replies appropriately. --ado -----Original Message----- From: Janne Snabb [mailto:snabb@epipe.com] Sent: Thursday, July 15, 2010 1:21 To: tz(a)lecserver.nci.nih.gov Subject: Europe/Finland DST correction for years 1981 and 1982 Hi, I noticed that the Finland data is not accurate for years 1981 and 1982. During these two first trial years the DST adjustment was made one hour earlier than in forthcoming years. Starting 1983 the adjustment was made according to the central European standards. This is documented in Heikki Oja: Aikakirja 2007, published by The Almanac Office of University of Helsinki, ISBN 952-10-3221-9, available online (in Finnish) at: http://almanakka.helsinki.fi/aikakirja/Aikakirja2007kokonaan.pdf Page 105 (56 in PDF version) has a handy table of all past daylight savings transitions. It is easy enough to interpret without Finnish skills. This is also confirmed by Finnish Broadcasting Company's archive at: http://www.yle.fi/elavaarkisto/?s=s&g=1&ag=5&t=&a=3401 The news clip from 1981 says that "the time between 2 and 3 o'clock does not exist tonight". Thus Paul Eggert's comment in the file (above the relevant entry) is indeed correct. Please see the diff at the bottom of this message. I believe that it produces the desired results. I am not a member of this list, so please CC me with any further correspondence. Best Regards, -- Janne Snabb / EPIPE Communications snabb(a)epipe.com - http://epipe.com/ --- europe.orig 2009-09-09 15:19:43.000000000 +0300 +++ europe 2010-07-15 07:29:53.000000000 +0300 @@ -1023,14 +1023,16 @@ # since 1981. Go with Strang instead. # # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Finland 1942 only - Apr 3 0:00 1:00 S Rule Finland 1942 only - Oct 3 0:00 0 - +Rule Finland 1981 1982 - Mar lastSun 2:00 1:00 S +Rule Finland 1981 1982 - Sep lastSun 3:00 0 - # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Europe/Helsinki 1:39:52 - LMT 1878 May 31 1:39:52 - HMT 1921 May # Helsinki Mean Time - 2:00 Finland EE%sT 1981 Mar 29 2:00 + 2:00 Finland EE%sT 1983 2:00 EU EE%sT # Aaland Is Link Europe/Helsinki Europe/Mariehamn

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Europe/Finland DST correction for years 1981 and 1982
by Janne Snabb July 15, 2010

July 15, 2010

Hi, I noticed that the Finland data is not accurate for years 1981 and 1982. During these two first trial years the DST adjustment was made one hour earlier than in forthcoming years. Starting 1983 the adjustment was made according to the central European standards. This is documented in Heikki Oja: Aikakirja 2007, published by The Almanac Office of University of Helsinki, ISBN 952-10-3221-9, available online (in Finnish) at: http://almanakka.helsinki.fi/aikakirja/Aikakirja2007kokonaan.pdf Page 105 (56 in PDF version) has a handy table of all past daylight savings transitions. It is easy enough to interpret without Finnish skills. This is also confirmed by Finnish Broadcasting Company's archive at: http://www.yle.fi/elavaarkisto/?s=s&g=1&ag=5&t=&a=3401 The news clip from 1981 says that "the time between 2 and 3 o'clock does not exist tonight". Thus Paul Eggert's comment in the file (above the relevant entry) is indeed correct. Please see the diff at the bottom of this message. I believe that it produces the desired results. I am not a member of this list, so please CC me with any further correspondence. Best Regards, -- Janne Snabb / EPIPE Communications snabb(a)epipe.com - http://epipe.com/ --- europe.orig 2009-09-09 15:19:43.000000000 +0300 +++ europe 2010-07-15 07:29:53.000000000 +0300 @@ -1023,14 +1023,16 @@ # since 1981. Go with Strang instead. # # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Finland 1942 only - Apr 3 0:00 1:00 S Rule Finland 1942 only - Oct 3 0:00 0 - +Rule Finland 1981 1982 - Mar lastSun 2:00 1:00 S +Rule Finland 1981 1982 - Sep lastSun 3:00 0 - # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Europe/Helsinki 1:39:52 - LMT 1878 May 31 1:39:52 - HMT 1921 May # Helsinki Mean Time - 2:00 Finland EE%sT 1981 Mar 29 2:00 + 2:00 Finland EE%sT 1983 2:00 EU EE%sT # Aaland Is Link Europe/Helsinki Europe/Mariehamn

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New time zone home (revisited)
by Olson, Arthur David (NIH/NCI) [E] July 14, 2010

July 14, 2010

It seems to have been overly ambitious to find both a new host and a new maintainter for the time zone stuff at the same time. So, one thing at a time. Who has insights on a workable options for new host(s) for the mailing list and the software distribution? --ado

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Double change on Apr 4th in America/Bahia_Banderas?
by Stuart Bishop July 14, 2010

July 14, 2010

Just looking into a failure in my test suite triggered by two timezone jumps within an hour: $ zdump -v America/Bahia_Banderas 2010 | grep 2010 America/Bahia_Banderas Sun Apr 4 06:59:59 2010 UTC = Sat Apr 3 23:59:59 2010 MST isdst=0 gmtoff=-25200 America/Bahia_Banderas Sun Apr 4 07:00:00 2010 UTC = Sun Apr 4 01:00:00 2010 CST isdst=0 gmtoff=-21600 America/Bahia_Banderas Sun Apr 4 07:59:59 2010 UTC = Sun Apr 4 01:59:59 2010 CST isdst=0 gmtoff=-21600 America/Bahia_Banderas Sun Apr 4 08:00:00 2010 UTC = Sun Apr 4 03:00:00 2010 CDT isdst=1 gmtoff=-18000 America/Bahia_Banderas Sun Oct 31 06:59:59 2010 UTC = Sun Oct 31 01:59:59 2010 CDT isdst=1 gmtoff=-18000 America/Bahia_Banderas Sun Oct 31 07:00:00 2010 UTC = Sun Oct 31 01:00:00 2010 CST isdst=0 gmtoff=-21600 Is this really correct, or should the timezone have jumped straight to CDT (-18000) at 0700 UTC? -- Stuart Bishop <stuart(a)stuartbishop.net> http://www.stuartbishop.net/

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Time zone confusion and implementation hints
by Yves Goergen July 10, 2010

July 10, 2010

Hi, I'm currently implementing an API for the tz database that should look like .NET's TimeZoneInfo class to replace that in my application. The API includes: * Convert a date and time from UTC to a time zone * Convert a date and time from a time zone to UTC * Return the base UTC offset of a time zone for a date and time * Return the save offset of a time zone for a date and time * Determine whether a date and time is ambiguous in a time zone * Determine whether a date and time is invalid in a time zone It will come with a code generator that "compiles" the text files into C# code so that there's no need to deploy additional files with the application. The API's internal data structures are very similar to the tz database records, these are already coded. Currently I'm stuck because of the flexibility of the tz rules. These can define transition times either in local, standard or universal time. Additionally, the caller of my API passes a date and time that is either local or universal. All this needs to be matched correctly. The right rule needs to be selected and there can be ambiguous or invalid times all along the way. It's not only hard to implement, it's also hard to describe, it's very confusing not to have a common base [zone] you can hold on to. I have now read about any manpage and code file from the tzcode distribution, starting with zic.c and going backwards in the list. I think the file localtime.c does the actual conversion but it's hard to read because it contains only few comments and uses short all-lowercase global variable names. I couldn't follow it to its core where the magic happens. I have analysed .NET's TimeZoneInfo implementation with .NET Reflector but it's not half as mighty as what the tz database can express. I also looked at the C# library ZoneInfo, but it uses an incompatible license, reads the text files at runtime and last but not least is quite inexact around transition times which it inacceptable for a calendar application. Also I think it's a good idea to write my own API for it because I'll need a Java port later as well, working on the exact same data. Could somebody assist me in this, please? Are there helpful thoughts to use when implementing such a programme? Right now my biggest problem is the transition times and in consequence finding the right rule to use for a given date and time. -- Yves Goergen "LonelyPixel" <nospam.list(a)unclassified.de> Visit my web laboratory at http://beta.unclassified.de

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Data request
by Rahim Bhimani July 9, 2010

July 9, 2010

Hello, Your website is useful. Thanks for managing the same. We tried to access your FTP site but were not able to get access of the same. Can you please send me the data through mail or let me know how else can we access the data. Would it be possible to get the data in following format : Country | City | timezone code | DST Start time | DST End time Will appreciate your prompt response. Warm Regards Rahim

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Olson programming language specific data sets
by Rich Tibbett July 4, 2010

July 4, 2010

Hi, I would like to request that the following resource be added to http://www.twinsun.com/tz/tz-link.htm: http://code.google.com/p/tzdata/ This project provides programming language specific representations of Olson timezone data. Currently this includes XML, PHP, Ruby, Javascript, JSON and CSV formatted data. The repository is updated as soon as the Olson FTP distribution is updated. All data can be downloaded as a zip and/or it can be obtained/synced via anonymous SVN. Data is made available under the MIT license. Thanks for all your hard work and I hope this resource will be of interest for people looking for language-specific timezone bindings. best regards, Rich Tibbett

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