- tz - lists.iana.org

time-zone designators
by LIVINGSTON Alex Dec. 9, 2006

Dec. 9, 2006

I am not in favour of alphabetic abbreviations as designators of time zones. First, their role is not well defined. Do they apply to A: a geographic region and its entire time-offset history and future, B: a particular single offset from UTC/GMT, or C: a particular set of two or more offsets from UTC/GMT and "rules" describing when changes from one of these offsets to another occur? Second, there seems to be no requirement for them to be globally or historically unique. I would support two types of time-offset designation: 1: a numeric specification of a single offset from UTC/GMT (e.g. -04:00) 2: a specification applying to a point on the earth's surface and indicating the entire history (and expected future history) of the time kept at that point by nearby human beings, as in the tz database (as I understand it) Actually, I might also consent to: 1A: a numeric specification of two (or more) offsets from UTC/GMT that apply periodically (e.g. +10:00/11:00), though only if such a specifier is unique in the context it is used in (+10:00/+11:00 applies both to Tasmania and mainland southeast Australia, but the two regions change from +10:00 to +11:00 at different times at present, so using that label for a zone as things currently stand would not be on) 2A: a specification applying to a well-defined, invariant region of the earth's surface and indicating the entire history (and expected future history) of the time kept by human beings occupying that region Type 1 is by far the easiest to work with, and perfectly adequate for single-instant specifications. Only if, for a particular geographic location, a period of time (including possibly a single date) or a repeating scheduled event is to be specified might a single offset not be up to the task. If some apparent standard abbreviated designator is not clear, a lot of effort seems to be put into crafting a "suitable" one for the field labelled (for reasons that aren't all that clear to me) "FORMAT" in the tzdata files. I get the impression that people derive a sense of security from the authority and credibility supposedly lent to time specifications by such labels. Only it is a false sense of security, I would contend. These abbreviations seem to be seized upon by implementors of time-management software as though "official" and indispensable and to be appended enthusiastically to time specifications. I would like to see such enthusiasm diverted to the use, instead, of far less ambiguous and far more informative and helpful designators (like type 1 especially). (I realise now that I have somewhat conflated time zones with time specifications. I don't think my comments are affected that much by this.) I hope I haven't strayed into territory outside the purview of this list.

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FW: time in southeastern Western Australia
by Olson, Arthur David (NIH/NCI) [E] Dec. 8, 2006

Dec. 8, 2006

I'm forwarding this message from Alex Livingston who, since sending it, has subscribed to the time zone mailing list. --ado -----Original Message----- From: LIVINGSTON Alex [mailto:lial@mac.com] Sent: Friday, December 08, 2006 1:03 AM To: tz(a)lecserver.nci.nih.gov Subject: re: time in southeastern Western Australia Further to my previous message, here is a link to a picture of the sign I referred to: http://www.confluence.org/photo.php?visitid=10280&pic=7 It shows that my memory did not serve me perfectly.

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re: time in southeastern Western Australia
by LIVINGSTON Alex Dec. 8, 2006

Dec. 8, 2006

Further to my previous message, here is a link to a picture of the sign I referred to: http://www.confluence.org/photo.php?visitid=10280&pic=7 It shows that my memory did not serve me perfectly.

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time in southeastern Western Australia
by LIVINGSTON Alex Dec. 8, 2006

Dec. 8, 2006

Apologies if this has already been covered. I checked the latest tzdata file and there seems to be no mention of it. I have been meaning to write this for nearly four years; it was just on four years ago that I drove along the Eyre Highway, which passes through eastern Western Australia close to the southern coast of the continent. I paid particular attention to the time kept there. There can be no dispute that UTC+08:45 was considered "the time" from the border village just inside the border with South Australia to as far west as just east of Caiguna. There can also be no dispute that Eucla is the largest population centre in this zone, having a population of "40 or 50" (from memory what the proprietor of the roadhouse said when I asked him); it even has named side streets off the highway, and a very modern meteorological observatory and office. The other settlements, Cocklebiddy, Madura, Mundrabilla, and the border village, have much smaller permanent populations (around a dozen at most). So if a new zone were to be added to the tz database it should be called "Australia/Eucla". To back up my assertions I was going to refer to photographs I took of the three clocks at the border crossing (showing, Perth, local, and Adelaide time, respectively) and of the clearly "official" sign (galvanised-steel posts and frame, well-cut rectangular sheet-metal plate with rounded corners, stencilled lettering, and reflective paint) proclaiming "Central Western Time" that is seen just after leaving Caiguna heading east, but I have not published them yet and I do not have the time to check them now. (I think the sign also says, in smaller lettering, "Advance Clocks 45 Minutes".) This zone is also shown on the excellent map at http://en.wikipedia.org/wiki/Image:Timezones_optimized.png (obviously based on the CIA time-zone map). "Central Western Time" is mentioned in http://en.wikipedia.org/wiki/Time_zone, where an estimated population for this region of 200 (according with what I would have guessed) is also given. (Unfortunately the phrase "Western Central Standard Time" is used in http://en.wikipedia.org/wiki/Time_in_Australia to refer to the same thing.) Now that Western Australia is observing daylight saving, the question arose whether this part of the state would follow suit. I just called the border village [+61 (0)8 9039-3474; from online white pages] and confirmed that indeed they have, meaning that they are now observing UTC+09:45. There is one more curiosity to report about this isolated part of the world. The old Eyre telegraph station, just behind the coastal sand dunes southeast of Cocklebiddy, is now run as a bird observatory as well as a weather station and guest house. Its permanent population is 2 (a caretaker couple). I stayed there for a night on my way through and noticed that they kept a time different both from Perth and "the highway" (phrase used by caretaker; see below); they have a clock in their kitchen with a Dymo label on it stating "Eyre Std. Time" (I took a picture). It was UT+09:00, meaning a whole hour ahead of Perth, making their checking and reporting of weather data (which the Perth weather bureau expects to be done according to Perth time) simpler. I have just called them [+61 (0)8 9039-3450, also from online white pages], and they too have advanced their clocks with the rest of the state, putting them on UTC+10:00 and maintaining their one-hour difference from Perth. As far as I'm concerned this warrants another time zone, Australia/Eyre, despite the tiny permanent population! I seem to remember that what matters to this list is what time people actually keep, not statutory status. I hope the hour or two I've spent preparing and writing this turns out to be of some value.

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Oddness in file interpretation - I assume I am missing something...
by Philip Warner Dec. 6, 2006

Dec. 6, 2006

The current files have the following zone & rules: Freetown Zone Africa/Freetown -0:53:00 - LMT 1882 -0:53:00 - FMT 1913 Jun # Freetown Mean Time -1:00 SL %s 1957 0:00 SL %s Rule SL 1935 1942 - Oct 1 0:00 0 WAT Rule SL 1957 1962 - Jun 1 0:00 1:00 SLST Rule SL 1957 1962 - Sep 1 0:00 0 GMT And zic produces, among others, the following transition: Africa/Freetown Sun Jun 1 00:52:59 1913 UTC = Sat May 31 23:59:59 1913 FMT isdst=0 Africa/Freetown Sun Jun 1 00:53:00 1913 UTC = Sat May 31 23:53:00 1913 WAT isdst=0 The problem/question I have is: based on the above rules, it is not at all clear to me that Sat May 31 23:53:00 1913 should be designated 'WAT'; in fact I would have thought there would be a case for it being 'FMT' since none if the 'SL' rules apply in 1913. This is further complicated by the following rules & zones: Zone Africa/Algiers 0:12:12 - LMT 1891 Mar 15 0:01 0:09:21 - PMT 1911 Mar 11 # Paris Mean Time 0:00 Algeria WE%sT 1940 Feb 25 2:00 1:00 Algeria CE%sT 1946 Oct 7 Rule Algeria 1916 only - Jun 14 23:00s 1:00 S Rule Algeria 1916 1919 - Oct Sun>=1 23:00s 0 - which for the transition in 1911 produces 'WET'; apparently *not* using the 'S' from the first rule. And this set: Zone Africa/Accra -0:00:52 - LMT 1918 0:00 Ghana %s Rule Ghana 1936 1942 - Sep 1 0:00 0:20 GHST Rule Ghana 1936 1942 - Dec 31 0:00 0 GMT which produces 'GMT' for the transition in 1918. Can someone confirm that zic is doing the right thing (which I kind of assume it is by definition), and perhaps give me a rule to follow when performing the %s substitutions? Any help would be greatly appreciated.

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Africa/Asmera / Africa/Asmara
by Klaus Klein Dec. 5, 2006

Dec. 5, 2006

Feedback from one of our users, forwarded with permission. I've checked with the usual suspects (i.e., diplomatic services' web sites), which confirm the Asmara spelling. - Klaus ----- Forwarded message from Zafer Aydogan <zafer(a)aydogan.de> ----- the city name of Asmera has changed to Asmara. Shall we update the name in the zoneinfo file ? /usr/share/zoneinfo/Africa/ Source: http://en.wikipedia.org/wiki/Asmera Zafer. ----- End forwarded message -----

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Cuba is back into the CST zone :-)
by Roger Pe�a Escobio Dec. 4, 2006

Dec. 4, 2006

Hi I am using CentOS-4.4 a clone of RHEL-4.4 and with the more recent updates to the tzdata package (tzdata-2006m) we move from Havana CST to the Havana CDT, then our servers just went 1 hour to the future :-) I look into the changelog and for cuba, inside the northamerica file you can find, I cuote: # From Steffen Thorsen (2006-08-17): # It is likely that they are not reverting back to standard time this # year either, based on the number of responses I have got from users # (when my site claimed Cuba will end DST on lastSun/October) but , as a matter of fact, we revert back to CST last October you can see the Steffen page now: http://www.timeanddate.com/worldclock/city.html?n=99 and the corresponding news in the newspapers: http://www.granma.cubaweb.cu/2006/10/27/nacional/artic03.html http://cubahora.co.cu/index.php?tpl=principal/ver-noticias/ver-not_soc.tpl.… I am placing a bug report into the RedHat Bugzilla also thanks in advance roger __________________________________________ RedHat Certified Engineer ( RHCE ) Cisco Certified Network Associate ( CCNA ) ____________________________________________________________________________________ Yahoo! Music Unlimited Access over 1 million songs. http://music.yahoo.com/unlimited

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Question about From & To rule fields...just t be certain I understand
by Philip Warner Dec. 3, 2006

Dec. 3, 2006

I'd like to clarify which year should be compared in from/to fields for rules (and zone lines). It seems reasonable that the AT field determines which year is to be compared (wallclock, utc or standard) -- is that correct? To give specific example: Rule Test 1999 only - Jan 1 0:00 2:00 - Rule Test 2000 only - Jan 1 0:00 0:00 - These are both wallclock rules, and suppose they are used in a region that is GMT+5. Then at UTC 31-Dec-1999 17:00 the WC time will turn to midnight....is that the point at which the clocks would be adjusted? And if so, in the following example: Rule Test 1999 only - Jan 1 0:00 2:00u - Rule Test 2000 only - Jan 1 0:00 0:00u - would the clocks adjust at UTC time 1-Jan-2000?

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Vzic indicates missing tz rules
by Andy McDonald Dec. 1, 2006

Dec. 1, 2006

I've been using 'vzic' (http://dialspace.dial.pipex.com/prod/dialspace/town/pipexdsl/s/asbm26/vzic/) to convert tz data to iCal. vzic 1.3 issues the following - hopefully self-explanatory warnings when run against tz/2006p: ----------------- andy@zanzibar:~/packages/vzic-1.3$ ./vzic --pure WARNING: Couldn't find a LETTER_S to use in FORMAT: C%sT in Zone: Asia/Macau Leaving TZNAME empty WARNING: Couldn't find a LETTER_S to use in FORMAT: TM%sT in Zone: Asia/Ashgabat Leaving TZNAME empty WARNING: Couldn't find a LETTER_S to use in FORMAT: CE%sT in Zone: Europe/Warsaw Leaving TZNAME empty WARNING: Couldn't find a LETTER_S to use in FORMAT: WE%sT in Zone: Atlantic/Azores Leaving TZNAME empty WARNING: Couldn't find a LETTER_S to use in FORMAT: Y%sT in Zone: America/Nome Leaving TZNAME empty WARNING: Couldn't find a LETTER_S to use in FORMAT: M%sT in Zone: America/Inuvik Leaving TZNAME empty WARNING: Couldn't find a LETTER_S to use in FORMAT: P%sT in Zone: America/Whitehorse Leaving TZNAME empty WARNING: Couldn't find a LETTER_S to use in FORMAT: P%sT in Zone: America/Dawson Leaving TZNAME empty andy@zanzibar:~/packages/vzic-1.3$ ----------------- (this is a slightly modified version of vzic - see below; the '--pure' option is not important). Following through in tz for America/Inuvik, we see: ----------------- # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule NT_YK 1918 only - Apr 14 2:00 1:00 D Rule NT_YK 1918 only - Oct 27 2:00 0 S ... Zone America/Inuvik -8:54:52 - LMT 1884 -8:00 NT_YK P%sT 1979 Apr lastSun 2:00 -7:00 NT_YK M%sT 1980 -7:00 Canada M%sT ----------------- Significantly, America/Inuvik is defined explicitly from the 1800's onwards, but the rule NT_YK is defined only from 1918, hence this missing 'LETTER/S'. Similar issues affect America/Whitehorse and America/Dawson. America/Nome uses the rule 'US' from 1943 to 1946, although the rule isn't defined for most of that period. Spot-checking the other problem zones indicates similar problems. I've exchanged a few e-mails with the developer of vzic; he pointed out that vzic works around most of the above 'problem' zones (see line 899 of vzic_output.c, v1.3); I commented out the workaround to derive the above output. With the workaround, vzic warns on Inuvik, Whitehorse and Dawson only. Andy

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register timezone mailing list
by Tri Duong Minh Nov. 30, 2006

Nov. 30, 2006

Hi All, I would like to join timezone mailing list. Could you please register for me? My information: Email: dmtri(a)tma.com.vn First name: Tri Full name: Duong Minh Tri Sex: Male Nationality: Vietnam Regards, Tri Duong Shasta - Application EXT: 5669

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