March 2005 - tz - lists.iana.org

Daylight Savings Time in Kazakhstan?!
by Stefan Hellwig March 17, 2005

March 17, 2005

Hi, I just subscribed to this list so please bear with me if this issue has been discussed already or does not fit in here... This week I was informed that the government of Kazakhstan has decided NOT to perform the "time switch" from winter to summer time anymore (it was mentioned in a local newspaper). Does anyone know if this is really the case and if there is a timezone definition file for that already? The current rule set for the Kazakh timezone Asia/Almaty says: [...] Rule RussiaAsia 1996 max - Oct lastSun 2:00s 0 - [...] Zone Asia/Almaty 5:07:48 - LMT 1924 May 2 # or Alma-Ata 5:00 - ALMT 1930 Jun 21 # Alma-Ata Time 6:00 RussiaAsia ALM%sT 1991 6:00 - ALMT 1992 6:00 RussiaAsia ALM%sT So right now it's scheduled for March 27 (lastSun) at 2:00am. If they don't do that switch anymore we'd have to change that timezone definition on our servers there... Can anyone confirm this "rumor"? Thanks & Regards, Stefan.

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Change in local time in Uruguay
by Eduardo Cota March 15, 2005

March 15, 2005

There has been a change in local time in Uruguay. The decree (dated 10 March 2005) can be found here. http://www.presidencia.gub.uy/_Web/decretos/2005/03/cm%205.PDF Basically it says that the summer time this year is extended until 27/3/2005, at 2:00. We changed our local zones (on a FreeBSD box) for the file southamerica in the following way: 1060c1060 < Rule Uruguay 2005 only - Mar Sun>=8 0:00 0 - --- > Rule Uruguay 2005 only - Mar 27 2:00 0 - Yours, Eduardo Cota.

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RE: Is more detailed timezone history desired?
by Olson, Arthur David (NIH/NCI) March 14, 2005

March 14, 2005

One possibility would be to take advantage of the name space; zic input such as... Zone Past/America/East-Podunk ... ...would segregate data for now-inactive time zones; this would make the data available without unduly cluttering the main directory and subdirectories. --ado

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Tzcode2005g.tar.gz and tzdata2005g.tar.gz
by Olson, Arthur David (NIH/NCI) March 14, 2005

March 14, 2005

The files... ftp://elsie.nci.nih.gov/pub/tzcode2005g.tar.gz ...and... ftp://elsie.nci.nih.gov/pub/tzdata2005g.tar.gz ...are now available; these reflect the changes circulated on the time zone mailing list last week by Paul Eggert (a change to current DST rules in Uruguay and an update to a link to time zone software). --ado

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Two more weeks with DST in Uruguay
by Steffen Thorsen March 12, 2005

March 12, 2005

Uruguay's DST was scheduled to end on Sunday, 2005-03-13, but in order to save energy; it was postponed two weeks, until 2005-03-27, at either 3 or 2 in the morning (I'm not quite sure because the automatic translation tools don't give a very good translation). The official announcement is available here (Spanish): http://www.presidencia.gub.uy/_Web/noticias/2005/03/2005031005.htm Some background information is available here (also Spanish): http://www.cncs.com.uy/?tc=nt&nt=2543 Best regards, Steffen

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FW: Who ist the maintainer of tzdata?
by Olson, Arthur David (NIH/NCI) March 12, 2005

March 12, 2005

Since sending this message Alois Treindl has joined the time zone mailing list. --ado -----Original Message----- From: Alois Treindl [mailto:alois@astro.ch] Sent: Thursday, March 10, 2005 5:24 AM To: tz(a)lecserver.nci.nih.gov Subject: Who ist the maintainer of tzdata? I have a project to expand tzdata. Summarizing shortly, the rough idea is to - add boundary descriptions to each area with a different timezone history so that with given coordinates it can automatically be determined to which timezone history 'table' a given location belongs. I am aware that many non-trivial issues of geo-information processing arise with such a goal. - add more details for the complicated timezone history of some countries, e.g. Canada, where other sources have identified more than 250 regions with different timezone history, whereas current tzdata has only 15 regions. I am aware that this is a large project which will require resources measured in man-years. I may be in a position to contribute/sponsor such resources. I would like to communicate with the current maintainers of tzdata about these ideas, and about the best approach for such an expansion. My motivation background is the field of serious astrology, where reliable timezone history information is an essential requirement. tzdata is doing an excellent job to provide reliable information for current timzones, but it lacks sadly (and understandably, given the complexity of the problem) in historical detail. Alois Treindl

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proposed tz change for Uruguay (plus tz-link update)
by Paul Eggert March 11, 2005

March 11, 2005

Here's a proposed change to the tz database to reflect the news from Uruguay. The tz rules for Uruguay are currently incorrect for time stamps past this Sunday. Thanks to Steffen Thorsen for the info about Uruguay. Also, this patch adds a link to VelaTerra's recent offer of free licenses to tz database contributors. =================================================================== RCS file: RCS/southamerica,v retrieving revision 2005.5 retrieving revision 2005.5.0.2 diff -pu -r2005.5 -r2005.5.0.2 --- southamerica 2005/02/07 21:19:42 2005.5 +++ southamerica 2005/03/11 23:31:13 2005.5.0.2 @@ -1063,8 +1063,12 @@ Rule Uruguay 1993 only - Feb 28 0:00 0 # From Eduardo Cota (2004-09-20): # The uruguayan government has decreed a change in the local time.... # http://www.presidencia.gub.uy/decretos/2004091502.htm -Rule Uruguay 2004 only - Sep Sun>=15 0:00 1:00 S -Rule Uruguay 2005 only - Mar Sun>=8 0:00 0 - +Rule Uruguay 2004 only - Sep 19 0:00 1:00 S +# From Steffen Thorsen (2005-03-11): +# Uruguay's DST was scheduled to end on Sunday, 2005-03-13, but in order to +# save energy ... it was postponed two weeks.... +# http://www.presidencia.gub.uy/_Web/noticias/2005/03/2005031005.htm +Rule Uruguay 2005 only - Mar 27 2:00 0 - # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone America/Montevideo -3:44:44 - LMT 1898 Jun 28 -3:44:44 - MMT 1920 May 1 # Montevideo MT =================================================================== RCS file: RCS/tz-link.htm,v retrieving revision 2005.6 retrieving revision 2005.6.0.2 diff -pu -r2005.6 -r2005.6.0.2 --- tz-link.htm 2005/03/01 13:44:11 2005.6 +++ tz-link.htm 2005/03/11 23:35:28 2005.6.0.2 @@ -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="2005-01-11" /> +<meta name="DC.Date" content="2005-03-11" /> <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" /> @@ -224,8 +224,10 @@ Java-specific format.</li> href="http://www1.tip.nl/~t876506/AboutTimeZonesHC.html">HyperCard time zones calculator</a> is a HyperCard stack.</li> <li><a -href="http://www.veladesigngroup.com/velaterra.html">VelaTerra</a> is -a Mac OS X program.</li> +href="http://www.veladg.com/velaterra.html">VelaTerra</a> is +a Mac OS X program. Its developers +<a href="http://www.veladg.com/tzoffer.html">offer free +licenses</a> to <code>tz</code> contributors.</li> <li><a href="http://www.cimmyt.org/timezone/">World Time Explorer</a> is a Microsoft Windows program.</li>

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RE: Is more detailed timezone history desired?
by Olson, Arthur David (NIH/NCI) March 10, 2005

March 10, 2005

Top priorities would be: 1. Ensure that the format of the time zone source files is adequate to represent historical changes. 2. Document changes since 1970-01-01 (the POSIX epoch). --ado -----Original Message----- From: Alois Treindl [mailto:alois@astro.ch] Sent: Thursday, March 10, 2005 4:54 PM To: tz(a)lecserver.nci.nih.gov Subject: Is more detailed timezone history desired? regarding my project to extend the details of timezone history in tzdata, a first question: Is it desirable, in the eyes of current tzdata maintainers, to add such extensions?

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Time zone: the next generation
by Olson, Arthur David (NIH/NCI) March 10, 2005

March 10, 2005

Time zone package: the next generation Over the last year we've done as much as possible, within the existing time zone package framework, to cope with systems with 64-bit time_t values. But the zone information compiler (zic) still produces binary files with 32-bit transition time values. Something's gotta give. As long as we're making changes, it's best to do as much as possible (to avoid the need for further change down the road). I've listed problems, approaches, and questions below. Much of this material is related to general matters of time rather than specific matters of time zones; my apologies. PROBLEMS * Future transition times/past transition times The binary files produced by zic record transition times as 32-bit values; times after the 2038 (or before 1901) cannot be represented. (The future limit can be extended to 2106 by treating the values as unsigned, but if that's done times before 1970 cannot be represented.) * Transitions in Israel Israel now goes back to standard time in the fall on the Saturday before Yom Kippur; there's no convenient way to represent this in the input to zic. * Julian-Gregorian transition Signed 32-bit time_t values can only represent years going back to 1901; this means that for most areas of the world the Gregorian calendar is in effect for all times representable by such a time_t. Signed 64-bit time_t values have a far greater range; the range always includes all instants when areas switched from Julian to Gregorian. There's no provision for handling the switch in the time zone package. (The transition happens at different times in different places; in addition to handling the jump over a number of days, there's also the matter of figuring out whether a year ending in 00 is a leap year in a particular place.) * Year zero Some year numbering schemes skip over the year zero; others do not. There's no provision for specifying whether or not to skip in the time zone package. * Early years of Julian calendar Leap years were inserted every three (rather than four) years early in the life of the Julian calendar; some leap years were skipped later to make up for this. Month lengths (and names) were also in flux for a while. Documentation of the glitches is shaky; there's no way to reflect what documentation we do have. * Pre-Julian calendars The time zone package cannot handle information about the Roman Republic calendar or any of its predecessors. * Non-Julian-Gregorian calendars The time zone package cannot handle information about non-Julian-Gregorian time schemes (Mayan, Martian, and so on). * Big Bang/Big Crunch Signed 64-bit time_t values have enough range to go back to theorized time of the Big Bang origin of the universe and thus back to the start of time itself. Some folks might want to fold all instants "before" the Big Bang in to that instant. At the other end, advocates of the Big Crunch theory might want to treat time_t values greater than the predicted Crunch instant as if they were the Crunch instant. There's no way to do such pegging in the time zone package. * Creation/Apocalypse Some folks might want to peg past times at a predicted time of Creation and peg future times at a predicted Apocalypse. APPROACHES * Do nothing Since things don't get sticky until at least 2037, it's possible to wait (at least for a while) before taking action. * Tweak the binary file format At the least this would involve widening stored transition times beyond 32 bits. It might also be necessary to widen offsets as a way of coping with Julian/Gregorian shifts and year zero skips. * Abandon binary files We're now operating on the "terminfo" model in which human-readable descriptions are converted to binary form (with some precomputation done) for use by programs. We could shift to the earlier "termcap" model, simply copying files such as "asia" and "northamerica" to a public directory and interpreting them at run time. This eliminates the need to change binary file formats (since such files disappear); there might still be a need to change the source file format if we wanted to do things such as handle Julian/Gregorian transitions. Responsibly taking this approach might involve learning why the termcap-to-terminfo transition occurred, and whether the reasons are still applicable in today's computing environment. * Preprocess We could change "zic" so that for each zone it outputs a file with only those Rule and Zone lines required for the zone; there could be some simplification of the output (such as expressing all times in UTC) to ease interpretation. Again there would be run-time interpretation, but the job would be scaled down (by pre-identification of relevant data) and simplified. * Change zic's output to another format We could take the vzic route of reading the existing source files and producing VZONEINFO format output. We might want to extend the VZONEINFO format (for example, to handle leap seconds). We might want to produce output in some other existing format, or in a newly designed format. QUESTIONS * Do we handle Julian/Gregorian transitions? * Do we allow control of skipping the year zero? * Do we handle early-Julian leap year variations? * Do we handle pegging of far-past and far-future times? * For each new of the above: * What default assumption should be used in zic and in run-time software? * Can the assumption be overridden in a time zone source file? If so, how? * Can the assumption be overridden using an environment variable? If so, how? * Can the assumption be overridden with function calls? If so, how? * Do we simplify handling of events tied to non-Gregorian-calendar-related events (such as Yom Kippur)? * Do we handle pre-Julian or non-Julian-Gregorian time schemes? * When Sherman types... %horton TZ=Europe/Rome wayback March 15 -44 ...will he and Mr. Peabody witness an assassination? So...before discussing any of the above in detail...are the problems, approaches, and questions above correct and complete? If not, what should be changed? --ado

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Timezone converstion
by Rajesh Vargheese March 10, 2005

March 10, 2005

Hello, I was trying to evaluate tz libs for timezone usage for my application. My need: Given a region id [ex. "America/New_York"] and a UTC time, i want to get the offset i need to get the time for that region. I also need the Day light savings to be accounted. Can I use the libtz library to do this. Please let me if there are any location where I can get some sample code in C/C++ to do this. I tried to get the old archive so that I can find an answer, but its erroring out. Thanks in advance, Rajesh

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