- tz - lists.iana.org

CST timezone that does not account for DST
by Nilesh Parmar July 31, 2015

July 31, 2015

Hello Team, How can we have CST timezone that does not account for DST ? Using the POSIX string, we can create a timezone called CST that is GMT+6 as follows: [root@hp-dl120gen9-01 ~]# TZ=:CST6 date Thu Jul 9 06:50:29 CST 2015 But this is not consitent if tzdata package is update. Also this does take into account DST change? Thanks, Nilesh P.

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Time zone identifiers in user interfaces
by Gilmore Davidson July 30, 2015

July 30, 2015

Hi, long time lurker here, finally throwing my voice into the ring. This is a follow-up to the “Time Zone City for China” thread a week ago (starting at http://mm.icann.org/pipermail/tz/2015-July/022480.html <http://mm.icann.org/pipermail/tz/2015-July/022480.html> ). What particularly caught my attention was the discussion about the use of time zone IDs in user interfaces. Paul Eggert: "The string 'Asia/Shanghai' is a tzdata-specific identifier, not intended to be visible to non-experts.” Guy Harris: "Several time zone selectors I've seen are lazily-written crap that either directly display the tzdb name or tweak it slightly by, for example, splitting it into continent and city and displaying them in a more "user-friendly" form.” Guy Harris: “> Looks like this logic is not well understood by the communities. Then we need to do a better job of explaining it to them.” Not to put too fine a point on it… Yes, there needs to be a better job done of explaining that the city names in time zone IDs should not be used in user interfaces. After reading that discussion I went looking through the tzdb files for guidance around the use of IDs in UIs. All I managed to find was this snippet in the Theory file, on line 385: This naming convention is not intended for use by inexperienced users to select TZ values by themselves (though they can of course examine and reuse existing settings). Distributors should provide documentation and/or a simple selection interface that explains the names; see the 'tzselect' program supplied with this distribution for one example. Given that the above snippet is around halfway through the file – and its wording still provides a fair bit of leeway – it’s not exactly enforcing the stronger opinions displayed on this list about how the IDs should be used. For some context, my domain knowledge is restricted to web sites/applications, so I can’t speak to the OS-level discussions in the previous thread. What I do know is how web developers deal with time zones, if they deal with them at all. For the most part, they use a library specific to their language of choice which slightly abstracts the tzdb data. There are two things these libraries have in common: 1. They use tzdb zone identifiers as the primary part of their API. 2. They don’t have any mentions in their documentation that these identifiers are not for public display. This is not me picking on time zone library authors, as I know that some of them are on this mailing list. My main point is that web developers are, for the most part, so abstracted from the tzdb source that the zone IDs are the only interface they know. Therefore the IDs are what they put in their selection UIs. There’s also the not-insignificant matter of localisation of display names (even Moment Timezone, referenced in tz-link.htm, notes in its API documentation: "Because these strings are generally localized, Moment Timezone does not provide any long names for zones.”). Personally, I didn’t know of the existence of CLDR until I started reading this mailing list. So, instead of dismissing zone-IDs-in-a-user-interface as “lazily written crap”, how about we: a) Acknowledge that most web-based UIs for picking time zones are written by developers who genuinely don’t know any better (I count my past self in this category) b) Make an effort to better educate them about recommended uses of the IDs. I am not intending for this to come across as antagonistic or facetious. I just genuinely want the quality of time zone selectors on the web to improve. Cheers, Gil

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[PROPOSED PATCH 1/2] * southamerica: Give source for 1965 Venezuela transition.
by Paul Eggert July 30, 2015

July 30, 2015

--- southamerica | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/southamerica b/southamerica index dcc063f..dd9235f 100644 --- a/southamerica +++ b/southamerica @@ -1734,6 +1734,10 @@ Zone America/Montevideo -3:44:44 - LMT 1898 Jun 28 # Venezuela # +# From Paul Eggert (2015-07-28): +# For the 1965 transition see Gaceta Oficial № 27.619 (1964-12-15), p 205.533 +# http://www.pgr.gob.ve/dmdocuments/1964/27619.pdf +# # From John Stainforth (2007-11-28): # ... the change for Venezuela originally expected for 2007-12-31 has # been brought forward to 2007-12-09. The official announcement was @@ -1745,6 +1749,6 @@ Zone America/Montevideo -3:44:44 - LMT 1898 Jun 28 # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone America/Caracas -4:27:44 - LMT 1890 -4:27:40 - CMT 1912 Feb 12 # Caracas Mean Time? - -4:30 - VET 1965 # Venezuela Time + -4:30 - VET 1965 Jan 1 0:00 # Venezuela T. -4:00 - VET 2007 Dec 9 3:00 -4:30 - VET -- 2.1.4

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Uruguay out of DST
by J J July 24, 2015

July 24, 2015

>> >>* Source: http://www.camtur.com.uy/index.php/noticias/281-se-derogo-decreto-del-cambi… <http://www.camtur.com.uy/index.php/noticias/281-se-derogo-decreto-del-cambi…> * >> That is a press release published by an organization lobbying for the change, >> and surely such a source is less reliable than the newspapers we're already citing. >> The whole thing is very mysterious, at least to this outsider. Here is the decree signed by the president of Uruguay, on presidency website, http://archivo.presidencia.gub.uy/sci/decretos/2015/06/cons_min_201.pdf

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Uruguay out of DST
by Steffen Thorsen July 24, 2015

July 24, 2015

According to media in Uruguay, it looks like they will not be using DST the coming summer: http://www.elobservador.com.uy/gobierno-resolvio-que-no-habra-cambio-horari… http://www.republica.com.uy/este-ano-no-se-modificara-el-huso-horario-en-ur… It is a bit unclear if this is just this coming summer, or a permanent change. Our English summary (will be updated when we know more details): http://www.timeanddate.com/news/time/uruguay-stops-dst-2015.html Best regards, Steffen Thorsen - timeanddate.com

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Time Zone City for China
by 寇含军 July 23, 2015

July 23, 2015

Dear Sir or Madam, I have a question that bothered me for many years since I started to use the Linux systems. When we, Chinese users, are selecting the desired timezone for our Linux boxes, we always feel weird that there has been no "Asia/Beijing". Instead we see "Asia/Shanghai" or "Asia/Chongqing". This might by how IANA "thinks" what the China timezone convention is, but SERIOUSLY this is not what we, Chinese users, are expecting. We would be very happy to see "Asia/Beijing" among the list. I googled that this question has been asked in many places to different maintainers or distributors, and finally I figured out that IANA is the ultimate upstream who can fix this issue. As a matter of fact, if you take a look at the Windows time zone settings dialog, Beijing is in the list, but no Shanghai. Please add ""Asia/Beijing" to the list. Please take it into consideration and thank you very much! Best Regards, Hanjun Kou, an ordinary Chinese Linux user

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Lack of "initial" transitions for some zones
by Jon Skeet July 22, 2015

July 22, 2015

I suspect this is just a matter of how the data has been specified, but it's a little odd... I'm looking at the output of zic for each zone, and almost all zones start with a "transition" for some timestamp in the long distant past - including fixed zones such as UTC and Etc/*. However, the legacy "root" zones of CET, EET, PST8PDT etc don't have this initial "transition" in the file - unless I'm misinterpreting it, which is always a possibility. Would it make sense to adjust either the data or zic to make all zic output (in the 8-byte-timestamp format, at least) cover all of time? I realize that this "extra" data (presumably an insertion of "standard time until the first transition") may well not be historically accurate - but I doubt that it would be any less accurate than other zones in a similar situation. Jon

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No DST for Uruguay since 2015
by Guillermo Pereyra July 20, 2015

July 20, 2015

http://archivo.presidencia.gub.uy/sci/decretos/2015/06/cons_min_201.pdf

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About the core city of a tz region
by David Patte ₯ July 20, 2015

July 20, 2015

I am curious about the protocol that tz uses to specify the name of each tz region. Is the core city in a region always the most populous city in the tz region? And what is done if a smaller city's population overtakes the named city? Is the zone renamed? Also, since historical data (pre-1970) is now maintained only for the named city in a region, does it not make sense to use the population as of 1970, since the historical records actually affected more people at that time?

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Zone America/Glace_Bay
by Hank W. July 20, 2015

July 20, 2015

I just read in Wikipedia that Glace Bay, Nova Scotia, Canada existed only from 1901 to 1995. The government of Glace Bay was dissolved on 1 Aug 1995 when eight municipalities, including Glace Bay, were consolidated to form Cape Breton (a.k.a. CBRM, short for Cape Breton Regional Municipality), which is currently the second-most populous municipality in Nova Scotia after Halifax. Wikipedia shows Cape Bretons coordinates as 46° 9 north latitude by 60° 10 west longitude. That longitude corresponds to a local mean time of UTC-4:00:40. https://en.wikipedia.org/wiki/Glace_Bay https://en.wikipedia.org/wiki/Cape_Breton_Regional_Municipality Hank Wisniewski of Austin, Texas, U.S.A.

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