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FW: Time Zone Data File Conventions
by Olson, Arthur David Oct. 17, 1997

Oct. 17, 1997

(Note that wally.wedel(a)central.sun.com is not on the time zone mailing list; be sure that a copy of any reply gets sent that way. --ado.) ---------- From: Waldo (Wally) Wedel [Sun Professional Services JDC][SMTP:wally.wedel@Central.Sun.COM] Sent: Wednesday, October 15, 1997 4:52 PM To: tz(a)elsie.nci.nih.gov Subject: Time Zone Data File Conventions Gentlemen: I am just finishing up implementing some general time zone classes in Java. I parse your data files and build time zone classes from them. Consequently, I have a few questions. 1) You use the concepts of "wall clock", "standard", and "GMT" time in specifying transition times. I'd like to verify just what these mean. a) Does "wall clock" mean simply take the time as given applying no corrections? b) Does "standard" mean apply DST time shift to given time to find true time? c) Does "GMT" mean apply GMT offset to given time to get true time? 2) Is the convention for rule naming that when searching for the applicable rule, one looks for a rule with the specified name covering the specified date? I assume that failure to find a rule implies no time shift. 3) The comments in the data files contain quite important information about the actual coded information. Have you considered converting them to HTML to get them better tagged? I'm particularly interested in tagging some kind of a long name usable in reports and like. I've been trying to figure out how to preserve them in an OODB so that they are properly associated with the data they describe. Thanks for any help you can provide. -- Wally Wedel Wally.Wedel(a)sun.com SunService Division (303) 804-3073 Java Design Center Fax: (303) 290-1696 5251 S DTC Parkway Englewood, CO 80111-2700

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FW: Time zone in Atikokan, Ontario, Canada
by Olson, Arthur David Oct. 17, 1997

Oct. 17, 1997

---------- From: msb@sq.com[SMTP:msb@sq.com] Sent: Wednesday, October 15, 1997 2:09 AM To: ado(a)elsie.nci.nih.gov Cc: eggert(a)twinsun.com Subject: Time zone in Atikokan, Ontario, Canada If I look at my road atlases, I see a nice straight-line boundary between Eastern and Central Time in Ontario, following the 90th west meridian from the boundary with Manitoba to that with Minnesota. Atikokan is located about 80 miles west of the 90th meridian and about 120 miles west of Thunder Bay. Article in the Toronto Star, 1997-10-14: | Atikokan asked to vote on daylight savings time | | ATIKOKAN (CP) -- Voters here are being asked to decide | what time it should be. | | Like Saskatchewan, this northwestern Ontario community | of 4,000 does not change to daylight savings time. | | That means clocks are an hour behind the rest of the | province in the summer months. | | The chamber of commerce wants the town on eastern time | year-round because it says most of the community's | business dealings are with clients in that region. | | The question will be on the ballot in the Nov. 10 | municipal election. Presumably this means that (1) either the Canadian Press or the Toronto Star is unaware that not all of Ontario observes Eastern Time, and (2) Atikokan has been been observing UTC-5 = Eastern Standard Time = Central Daylight Time all year, and now proposes to move to Eastern Time. I thought the tz mailing list might be interested, if they hadn't already heard. I'm afraid I have no idea which level of government has official jurisdiction on the question here.

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Time Zone Data File Conventions
by Waldo (Wally) Wedel [Sun Professional Services JDC] Oct. 15, 1997

Oct. 15, 1997

Gentlemen: I am just finishing up implementing some general time zone classes in Java. I parse your data files and build time zone classes from them. Consequently, I have a few questions. 1) You use the concepts of "wall clock", "standard", and "GMT" time in specifying transition times. I'd like to verify just what these mean. a) Does "wall clock" mean simply take the time as given applying no corrections? b) Does "standard" mean apply DST time shift to given time to find true time? c) Does "GMT" mean apply GMT offset to given time to get true time? 2) Is the convention for rule naming that when searching for the applicable rule, one looks for a rule with the specified name covering the specified date? I assume that failure to find a rule implies no time shift. 3) The comments in the data files contain quite important information about the actual coded information. Have you considered converting them to HTML to get them better tagged? I'm particularly interested in tagging some kind of a long name usable in reports and like. I've been trying to figure out how to preserve them in an OODB so that they are properly associated with the data they describe. Thanks for any help you can provide. -- Wally Wedel Wally.Wedel(a)sun.com SunService Division (303) 804-3073 Java Design Center Fax: (303) 290-1696 5251 S DTC Parkway Englewood, CO 80111-2700

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sri lanka timezone
by itojun＠itojun.org Oct. 15, 1997

Oct. 15, 1997

Could this be merged into FreeBSD 2.2.5-RELEASE? (and other appropriate database repositories) For details, see FreeBSD problem report #3775. http://www.freebsd.org/cgi/query-pr.cgi?pr=3775 itojun ------- Forwarded Message Return-Path: samath(a)slt.lk Return-Path: samath(a)slt.lk Received: from lakdiva.slt.lk (lakdiva.slt.lk [204.143.96.17]) by coconut.itojun.org (8.8.5/3.6Wbeta6) with ESMTP id PAA10698 for <itojun(a)itojun.org>; Wed, 15 Oct 1997 15:56:53 +0900 (JST) Received: from Penta.sth.slt.lk (colombo4-tty7.slt.lk [204.143.98.135]) by lakdiva.slt.lk (8.7.5/8.7.3) with SMTP id MAA05854 for <itojun(a)itojun.org>; Wed, 15 Oct 1997 12:56:27 +0600 (GMT+0600) Message-Id: <2.2.32.19971015125504.009fcb84(a)slt.lk> X-Sender: samath(a)slt.lk X-Mailer: Windows Eudora Pro Version 2.2 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Wed, 15 Oct 1997 12:55:04 +0000 To: Jun-ichiro Itoh <itojun(a)itojun.org> From: Samath Wijesundera <samath(a)slt.lk> Subject: Re: conf/3775: Time Zone for Sri Lanka - LKT X-Filter: mailagent [version 3.0 PL56] for itojun(a)itojun.org Yes the time zone of Sri Lanka is now different it is GMT + 6:00 now, it will be the Sri Lanka's Permanent time zone ! The following is correct # <URL:http://www.virtual-pc.com/lankaweb/news/items/240596-2.html> (1996-05-24) # reported ``the country's standard time will be put forward by one hour at # midnight Friday (1830 GMT) `in the light of the present power crisis'.'' # Transitions before 1996 are from Shanks (1991). # # From Dharmasiri Senanayake, Sri Lanka Media Minister (1996-10-24), as quoted # in <URL:news:54rka5$m5h@mtinsc01-mgt.ops.worldnet.att.net> (1996-10-26): # With effect from 12.30 a.m. on 26th October 1996 # Sri Lanka will be six (06) hours ahead of GMT. # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Asia/Colombo 5:19:24 - LMT 1880 5:20 - CEYT 1906 # Ceylon Time 5:30 - IST 1942 Jan 5 5:30 0:30 IHST 1942 Sep 5:30 1:00 IST 1945 Oct 16 2:00 5:30 - IST 1996 May 25 0:00 6:30 - LKT 1996 Oct 26 0:30 6:00 - LKT - - Samath At 02:42 PM 10/15/97 +0900, you wrote: >I don't know if it is correct, but do you mean the following >line in >http://www.freebsd.org/cgi/cvsweb.cgi/src/share/zoneinfo/asia?rev=1.11 >should be changed? > 6:30 - LKT # Sri Lanka Time > > ------- End of Forwarded Message

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Does Aix support this code???
by Briggman, Monica Oct. 14, 1997

Oct. 14, 1997

Does this timezone data and code work on AIX ?? Thanks, Monica

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RE: references to `africa' file for zone naming and abbrev. conve ntions.
by Olson, Arthur David Oct. 9, 1997

Oct. 9, 1997

> A minor nit, but when the zone naming and abbreviation conventions > were moved from tzdata/africa to tzcode/Theory cooresponding cross > references in the comments (See the `africa' file for time zone naming > and abbreviation conventions) comments in other data files were not > updated. Thanks for the catch. I've simply eliminated the cross references to avoid dangling pointers to a "Theory" file that some vendors may not distribute. Folks can expect to see the deletions (or rather not see them) the next time a tzdata archive goes out. --ado

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references to `africa' file for zone naming and abbrev. conventions.
by J.T. Conklin Oct. 9, 1997

Oct. 9, 1997

A minor nit, but when the zone naming and abbreviation conventions were moved from tzdata/africa to tzcode/Theory cooresponding cross references in the comments (See the `africa' file for time zone naming and abbreviation conventions) comments in other data files were not updated. --jtc

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RE: Proposed magic number patch
by Olson, Arthur David Oct. 8, 1997

Oct. 8, 1997

Is there a "magic number registration authority" (or an equivalent) to be in touch with either before or after deciding on one? --ado

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Re: Proposed magic number patch
by ncm＠cantrip.org Oct. 8, 1997

Oct. 8, 1997

John Cowan wrote: > Chris Newman wrote: > > Excellent idea, but I'd suggest choosing a magic number based on the > > principles outlined in RFC 2083 section 12.11. I propose: > > > > \211 T Z \r \n ^Z \n > > > > as a magic number. > > Thanks for the reference to RFC 2083. I have two problems: > > 1) 7 bytes is a "peculiar" length. I suggest adding a NUL > (\0) byte just after the Z, if we go with this scheme. > In which case "strncpy" will have to be replaced with > "memcpy". > > 2) There are only 20 available bytes. I am a little > reluctant to consume 8 of them, leaving at most 3 > new 32-bit length quantities. Consuming only 4 > is less risky. I agree that seven bytes is a bit long. PNG format files suffer indignities that I don't think the TZ records need to defend against. I don't know why "^T ^Z" would be insufficient. In addition, though, I'd like to see a version sequence number too, so that if the less-than-20 bytes of slop remaining prove insufficient, we have a recourse. I maintain that advisory timestamps: - when the information was entered - when the information was last known to be current - when the information will no longer be officially trustworthy (24 hours later, by default) - when the local installation will no longer consider the information current (perhaps longer, perhaps shorter, by preference) would be a useful addition to the format, in support of incremental network caching. Of course, we should also move to a 64-bit external time representation as soon as possible, which would also be the first increment of the version sequence number. Nathan Myers ncm(a)cantrip.org

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Proposed magic number patch
by John Cowan Oct. 8, 1997

Oct. 8, 1997

The following patch adds a "magic number" to compiled zoneinfo files. The affected files are zic.c and tzfile.h. In essence, the first four bytes of zoneinfo files are set to "\0x14\0x1a\0x54\0x5a", which in ASCII is "^T^ZTZ". This patch is trivial, but will assist in the automatic recognition of zoneinfo files by the Unix "file" command. *** tzfile.h Sat Jul 19 13:14:50 1997 --- tzfile.new.h Tue Oct 7 16:36:24 1997 *************** *** 46,52 **** */ struct tzhead { ! char tzh_reserved[20]; /* reserved for future use */ char tzh_ttisgmtcnt[4]; /* coded number of trans. time flags */ char tzh_ttisstdcnt[4]; /* coded number of trans. time flags */ char tzh_leapcnt[4]; /* coded number of leap seconds */ --- 46,53 ---- */ struct tzhead { ! char tzh_magic[4]; /* magic string: "^T^ZTZ" */ ! char tzh_reserved[16]; /* reserved for future use */ char tzh_ttisgmtcnt[4]; /* coded number of trans. time flags */ char tzh_ttisstdcnt[4]; /* coded number of trans. time flags */ char tzh_leapcnt[4]; /* coded number of leap seconds */ *** zic.c Tue Sep 23 16:37:14 1997 --- zic.new.c Tue Oct 7 16:34:30 1997 *************** *** 1468,1473 **** --- 1468,1475 ---- convert(eitol(typecnt), tzh.tzh_typecnt); convert(eitol(charcnt), tzh.tzh_charcnt); #define DO(field) (void) fwrite((void *) tzh.field, (size_t) sizeof tzh.field, (size_t) 1, fp) + strncpy(tzh.tzh_magic, "\0x14\0x1a\0x54\0x5a", 4); + DO(tzh_magic); DO(tzh_reserved); DO(tzh_ttisgmtcnt); DO(tzh_ttisstdcnt); -- John Cowan http://www.ccil.org/~cowan cowan(a)ccil.org e'osai ko sarji la lojban

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