- tz - lists.iana.org

DST on Twitter :-)
by Sergiusz Wolicki Sept. 9, 2020

Sept. 9, 2020

User Brent Terhune (@BrentTerhune) wrote at 9:55 PM on Sep 9: The guy who invented Daylight Saving was ahead of his time. Or behind, depending on which month it was. (https://twitter.com/BrentTerhune/status/1303784188584300545?s=03) -- Sergiusz

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timezone DB distribution
by Juergen Naeckel Sept. 8, 2020

Sept. 8, 2020

Hey there, First of all, I would like to thank you. I have to implement something in JavaScript that uses timezones. However, I am using an older JS version that does not have the flexibility like today’s JS. So I was looking for a repository holding all current timezones and rules for it, rather then me, checking time and again how which timezone is configured 😉 This really could help me. Reading through the files, it sometimes made me chuckle and I was actually surprised how fluent timezones are handled. Changes almost every year… I would like to recommend some improvements. I know you have pretty stable release by now. I am aware that changes probably to the structure might affect a lot of people/projects. However… First of all, a tar.gz is Linux specific. True, you could install additional Windows software. But, that might not go well with customers of mine. I think a ZIP would be acceptable for both worlds. Since I was interested in the repository, I downloaded the “Data only distribution”. I found six files containing the TZ information. And I found 27 files, containing other stuff. Well, there might be three or four files in a grey zone (calendars, backlist…). But I definitely do not consider MAKEFILE and .awk file as part of a “data only distribution”. Maybe move them to a separate folder in the GZ file? Finally, I got one more recommendation/question. I had read the readme file but it didn’t explain the data I saw in the files. It took me a while to understand the concept of the data structure. Some info of what to see in the file, and how to read it would help. And I think the first line of the ZONE definition contains some inconsistency (maybe I still didn’t understand it correctly). Below is a screenshot. See the first line for the zones? It looks mismatched with the New York. The RULE and the [UNTIL] are probably in the wrong column. Format is probably missing. [cid:image002.png@01D674A5.27F71B60] Then I noticed that the open-end validity. For rules it is denoted as “max” and for zones it is just a <blank>. Could we get some consistency here? And finally here comes my question: In the rules, I see in the column several times denoted with a tailing “u” or “s”. I think I read on one occasion that the times are denoted in “standard time”. I do not recall anymore where that was. But regardless, 1. I don’t understand what that “denoted in standard time” would mean 2. I definitely have no clue would the tailing “u”: would imply. [cid:image003.png@01D674A6.99550F50] Can you shed some light on this? Thank you! Not only for an answer but also for researching and compiling this list. Juergen Juergen Naeckel PRINCIPAL ARCHITECT T 617 766 2381 | C 617 775 3874 naeckel(a)adobe.com [cid:image001.png@01D6749A.D7B33580]

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Iceland stays put on time zone
by Paul Eggert Sept. 7, 2020

Sept. 7, 2020

After more than two years of discussion, Iceland's government decided not to move its time zone back to -01, where it was before daylight saving time was introduced. Currently Iceland is at +00, effectively permanent DST. Proponents of changing back had argued that DST has harmful effects on human health. To counteract DST's health effects, the government decided instead to launch an educational campaign to get Icelanders to sleep more. It is also considering monitoring children's sleep habits and starting school days later. See: Gréta Sigríður Einarsdóttir, Iceland’s Time Zone to Remain Unchanged. Iceland Review. 2020-09-01. https://www.icelandreview.com/sci-tech/icelands-time-zone-to-remain-unchang…

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DST in the news
by Arthur David Olson Aug. 29, 2020

Aug. 29, 2020

"American Academy of Sleep Medicine calls for elimination of daylight saving time" https://aasm.org/american-academy-of-sleep-medicine-calls-for-elimination-o… (Use your browser's vertical scroll bar to move through the article while avoiding an obscuring popup.) Noted on @Twitter by @AASMorg and retweeted by Jef Poskanzer (@JefPosk): https://twitter.com/AASMorg/status/1299334700478201858 @dash dashado

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[PROPOSED] * asia: Cite Barak 2020 on Israeli DST controversy.
by Paul Eggert Aug. 23, 2020

Aug. 23, 2020

--- asia | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/asia b/asia index 106efad..fff9a10 100644 --- a/asia +++ b/asia @@ -1699,6 +1699,10 @@ Zone Asia/Baghdad 2:57:40 - LMT 1890 # Israel +# For more info about the motivation for DST in Israel, see: +# Barak Y. Israel's Daylight Saving Time controversy. Israel Affairs. +# 2020-08-11. https://doi.org/10.1080/13537121.2020.1806564 + # From Ephraim Silverberg (2001-01-11): # # I coined "IST/IDT" circa 1988. Until then there were three -- 2.25.4

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ta and VBA
by Marlon Rosenthal Aug. 22, 2020

Aug. 22, 2020

Hello there, I am working on a private research procedure where I would like to use your database. Unfortunately I am working in Excel/VBA and have not found any link or advice how to use it with VBA. I hope there is something and maybe you can help me with a link? Best regards, Marlon Marlon Rosenthal german voice-over [image: Logo] <http://www.sprecherprofi.de/> sprecherprofi | +49 163 6002666 | marlon(a)sprecherprofi.de [image: Banner] <http://www.sprecherprofi.de/>

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XKCD Comic
by stevejones＠ontimezone.com Aug. 19, 2020

Aug. 19, 2020

While this comic neither represents the strength of the TZ infrastructure or the significant body of persons who contribute to and maintain it, I thought this still provided an amusing way to look at it: https://xkcd.com/2347/ Steve Jones

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Change Request: Europe/Kiev to Europe/Kyiv
by Victor Perov Aug. 16, 2020

Aug. 16, 2020

Dear Sir/Madam, I hope this email finds you well. I'm writing to you with a request to accept proposed changes of correcting the spelling of capital of Ukraine Kyiv in the Time Zone Database. I've found previously closed PR with the same intention. It was about renaming Kyiv and other two cities of Ukraine: Uzhhorod and Zaporizhia. It was closed 4y ago with no changes applied. I am deeply sorry for comments left by their authors in that PR. Those messages were sounding offensive and I understand your decision of closing that PR with no decision made. I agree, 4y ago the usage of Kiev was much wider than nowadays, and believe you will find materials I attached to my PR meaningful. The link to PR I've brought to your attention: https://github.com/eggert/tz/pull/27 I have also attached a patch of the commit to the email. Looking forward to hearing from you. Kind regards, Viktor Perov

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[PROPOSED 1/2] Minor editorial improvements for newstrftime.3
by Paul Eggert Aug. 15, 2020

Aug. 15, 2020

* newstrftime.3: Improve this a bit to have it match POSIX better. Resurrect the BSD manual’s phase-of-the-moon joke. --- newstrftime.3 | 103 ++++++++++++++++++++++++++++++++------------------ 1 file changed, 66 insertions(+), 37 deletions(-) diff --git a/newstrftime.3 b/newstrftime.3 index df38d1a..63842c7 100644 --- a/newstrftime.3 +++ b/newstrftime.3 @@ -50,12 +50,14 @@ strftime \- format date and time .B cc ... \-ltz .fi .SH DESCRIPTION -.ie '\(en'' .ds en \- -.el .ds en \(en .ie '\(lq'' .ds lq \&"\" .el .ds lq \(lq\" .ie '\(rq'' .ds rq \&"\" .el .ds rq \(rq\" +.de c +.ie \n(.g \f(CW\\$1\fP\\$2 +.el \\$1\\$2 +.. .de q \\$3\*(lq\\$1\*(rq\\$2 .. @@ -63,7 +65,7 @@ The .B strftime function formats the information from .I timeptr -into the buffer +into the array pointed to by .I buf according to the string pointed to by .IR format . @@ -72,24 +74,24 @@ The .I format string consists of zero or more conversion specifications and ordinary characters. -All ordinary characters are copied directly into the buffer. +All ordinary characters are copied directly into the array. A conversion specification consists of a percent sign .Ql % and one other character. .PP No more than .I maxsize -characters are placed into the array. -If the total number of resulting characters, including the terminating -null character, is not more than +bytes are placed into the array. +If the total number of resulting bytes, including the terminating +NUL character, is not more than .IR maxsize , .B strftime -returns the number of characters in the array, not counting the -terminating null. -Otherwise, zero is returned. +returns the number of bytes placed into the array, not counting the +terminating NUL. +Otherwise, zero is returned and the array contents are unspecified. .PP Each conversion specification is replaced by the characters as -follows which are then copied into the buffer. +follows which are then copied into the array. .TP %A is replaced by the locale's full weekday name. @@ -105,99 +107,122 @@ is replaced by the locale's abbreviated month name. .TP %C is replaced by the century (a year divided by 100 and truncated to an integer) -as a decimal number (00\*(en99). +as a decimal number [00,99]. .TP %c is replaced by the locale's appropriate date and time representation. .TP %D -is replaced by the date in the format %m/%d/%y. +is equivalent to +.c %m/%d/%y . .TP %d -is replaced by the day of the month as a decimal number (01\*(en31). +is replaced by the day of the month as a decimal number [01,31]. .TP %e -is replaced by the day of month as a decimal number (1\*(en31); +is replaced by the day of month as a decimal number [1,31]; single digits are preceded by a blank. .TP %F -is replaced by the date in the format %Y\*-%m\*-%d. +is equivalent to +.c %Y-%m-%d +(the ISO 8601 date format). .TP %G is replaced by the ISO 8601 year with century as a decimal number. +See also the +.c %V +conversion specification. .TP %g -is replaced by the ISO 8601 year without century as a decimal number (00\*(en99). +is replaced by the ISO 8601 year without century as a decimal number [00,99]. +This is the year that includes the greater part of the week. +(Monday as the first day of a week). +See also the +.c %V +conversion specification. .TP %H -is replaced by the hour (24-hour clock) as a decimal number (00\*(en23). +is replaced by the hour (24-hour clock) as a decimal number [00,23]. .TP %I -is replaced by the hour (12-hour clock) as a decimal number (01\*(en12). +is replaced by the hour (12-hour clock) as a decimal number [01,12]. .TP %j -is replaced by the day of the year as a decimal number (001\*(en366). +is replaced by the day of the year as a decimal number [001,366]. .TP %k -is replaced by the hour (24-hour clock) as a decimal number (0\*(en23); +is replaced by the hour (24-hour clock) as a decimal number [0,23]; single digits are preceded by a blank. .TP %l -is replaced by the hour (12-hour clock) as a decimal number (1\*(en12); +is replaced by the hour (12-hour clock) as a decimal number [1,12]; single digits are preceded by a blank. .TP %M -is replaced by the minute as a decimal number (00\*(en59). +is replaced by the minute as a decimal number [00,59]. .TP %m -is replaced by the month as a decimal number (01\*(en12). +is replaced by the month as a decimal number [01,12]. .TP %n is replaced by a newline. .TP %p -is replaced by the locale's equivalent of either AM or PM. +is replaced by the locale's equivalent of either +.q AM +or +.q PM . .TP %R -is replaced by the time in the format %H:%M. +is replaced by the time in the format +.c %H:%M . .TP %r is replaced by the locale's representation of 12-hour clock time using AM/PM notation. .TP %S -is replaced by the second as a decimal number (00\*(en60). +is replaced by the second as a decimal number [00,60]. +The range of +seconds is [00,60] instead of [00,59] to allow for the periodic occurrence +of leap seconds. .TP %s -is replaced by the number of seconds since the Epoch (see newctime(3)). +is replaced by the number of seconds since the Epoch (see +.BR ctime (3)). .TP %T -is replaced by the time in the format %H:%M:%S. +is replaced by the time in the format +.c %H:%M:%S . .TP %t is replaced by a tab. .TP %U is replaced by the week number of the year (Sunday as the first day of -the week) as a decimal number (00\*(en53). +the week) as a decimal number [00,53]. .TP %u is replaced by the weekday (Monday as the first day of the week) -as a decimal number (1\*(en7). +as a decimal number [1,7]. .TP %V is replaced by the week number of the year (Monday as the first day of -the week) as a decimal number (01\*(en53). If the week containing January +the week) as a decimal number [01,53]. If the week containing January 1 has four or more days in the new year, then it is week 1; otherwise it is week 53 of the previous year, and the next week is week 1. +The year is given by the +.c %G +conversion specification. .TP %W is replaced by the week number of the year (Monday as the first day of -the week) as a decimal number (00\*(en53). +the week) as a decimal number [00,53]. .TP %w is replaced by the weekday (Sunday as the first day of the week) -as a decimal number (0\*(en6). +as a decimal number [0,6]. .TP %X is replaced by the locale's appropriate time representation. @@ -209,7 +234,7 @@ is replaced by the locale's appropriate date representation. is replaced by the year with century as a decimal number. .TP %y -is replaced by the year without century as a decimal number (00\*(en99). +is replaced by the year without century as a decimal number [00,99]. .TP %Z is replaced by the time zone abbreviation, @@ -217,7 +242,7 @@ or by the empty string if this is not determinable. .TP %z is replaced by the offset from the Prime Meridian -in the format +HHMM or \*-HHMM as appropriate, +in the format +HHMM or \*-HHMM (ISO 8601) as appropriate, with positive values representing locations east of Greenwich, or by the empty string if this is not determinable. The numeric time zone abbreviation \*-0000 is used when the time is @@ -231,7 +256,9 @@ time zone abbreviation begins with is replaced by a single %. .TP %+ -is replaced by the date and time in date(1) format. +is replaced by the locale's date and time in +.BR date (1) +format. .SH SEE ALSO date(1), getenv(3), @@ -239,3 +266,5 @@ newctime(3), newtzset(3), time(2), tzfile(5) +.SH BUGS +There is no conversion specification for the phase of the moon. -- 2.17.1

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tz database update on a publication & thank-you.
by Andrew Lyon Aug. 3, 2020

Aug. 3, 2020

Several months ago I posted queries about the tz database to this discussion list as I investigated a series of errors triggered in software used to order and report clinical laboratory tests in our hospital network. Our main software system uses universal time for date& time of birth a recently added peripheral system (based on Android OS, and Java Joda-time that relies on the tz database) that triggered the peripheral system to freeze every few weeks. Investigation revealed that there were 10 years (between 1935 and 1945) in the America/Regina tz time zone data where the transition to daylight saving time occurred at midnight on spring transition dates. If our hospital (which is in the America/Regina time zone) encountered patients born on one of those spring daylight savings time transitions dates 1935-1945, the system froze, because the hour of birth was usually unknown and was assigned to midnight local time by default, and midnight local time on those dates does not map back to universal time. A software patch was quickly developed by the software provider and this susceptibility is now avoided. I understand now that this type of situation is well known to members of this group. I want to pass on a 'thank-you' to the tz database community for their helpful messages as this case was investigated. A description of this investigation was published today in the Journal of Applied Laboratory Medicine: "No Lab Tests" When You Are Born in The Twilight Zone: A Clinical Informatics Case Report. [ https://pubmed.ncbi.nlm.nih.gov/32728691/ | https://pubmed.ncbi.nlm.nih.gov/32728691/ ] best wishes, Andrew Dr. A.W. Lyon Dept Pathology and Laboratory Medicine University of Saskatchewan, SK, Canada

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[PATCH] Update Bahrain as per article in The National
by Paul Eggert July 25, 2020

July 25, 2020

* backzone (Asia/Bahrain): Adjust transitions before 1944 to match Ashleigh Stewart’s article in today’s The National (Abu Dhabi). --- backzone | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/backzone b/backzone index 91fa21d..7cf026d 100644 --- a/backzone +++ b/backzone @@ -459,7 +459,22 @@ Zone Asia/Aden 2:59:54 - LMT 1950 3:00 - +03 # Bahrain -Zone Asia/Bahrain 3:22:20 - LMT 1920 # Manamah +# +# From Paul Eggert (2020-07-22): +# Most of this data comes from: +# Stewart A. Why Gulf Standard Time is far from standard: the fascinating story +# behind the time zone's invention. The National (Abu Dhabi). 2020-07-22. +# https://www.thenational.ae/arts-culture/why-gulf-standard-time-is-far-from-… +# Stewart writes that before 1940 some companies in Bahrain were at +0330 and +# others at +0323. Reginald George Alban, a British political agent based in +# Manama, worked to standardize this, and from 1941-07-20 Bahrain was at +# +0330. However, BOAC asked that clocks be moved to gain more light at day's +# end, so Bahrain switched to +04 on 1944-01-01. +# +# We don't know when companies chose +0330 or +0323 before 1940; for now +# assume that there was no real standard in Bahrain before 1941-07-20. +Zone Asia/Bahrain 3:22:20 - LMT 1941 Jul 20 # Manamah + 3:30 - +0330 1944 Jan 1 4:00 - +04 1972 Jun 3:00 - +03 -- 2.17.1

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Re: [tz] Fwd: DST changes in Hungary (full historical revision)
by Paul Eggert July 25, 2020

July 25, 2020

Thanks for those corrections. I installed the attached patch to the development database on GitHub. It's not exactly what you emailed me, but it should generate equivalent transitions. It'd help if we could list citations for the transitions; are URLs available for each decree etc. that you consulted? We could add them as comments. Thanks again.

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[PROPOSED] * backzone: More commentary re 1940s Bahrain.
by Paul Eggert July 23, 2020

July 23, 2020

--- backzone | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/backzone b/backzone index 7cf026d..f2684b4 100644 --- a/backzone +++ b/backzone @@ -460,19 +460,31 @@ Zone Asia/Aden 2:59:54 - LMT 1950 # Bahrain # -# From Paul Eggert (2020-07-22): +# From Paul Eggert (2020-07-23): # Most of this data comes from: # Stewart A. Why Gulf Standard Time is far from standard: the fascinating story # behind the time zone's invention. The National (Abu Dhabi). 2020-07-22. # https://www.thenational.ae/arts-culture/why-gulf-standard-time-is-far-from-… -# Stewart writes that before 1940 some companies in Bahrain were at +0330 and +# Stewart writes that before 1941 some companies in Bahrain were at +0330 and # others at +0323. Reginald George Alban, a British political agent based in # Manama, worked to standardize this, and from 1941-07-20 Bahrain was at # +0330. However, BOAC asked that clocks be moved to gain more light at day's # end, so Bahrain switched to +04 on 1944-01-01. # -# We don't know when companies chose +0330 or +0323 before 1940; for now -# assume that there was no real standard in Bahrain before 1941-07-20. +# Re the 1941 transition, Stewart privately sent me this citation: +# "File 16/53 Enquiries Re: Calculation of Local Time", British Library: India +# Office Records and Private Papers, IOR/R/15/2/1564, in Qatar Digital Library +# https://www.qdl.qa/archive/81055/vdc_100000000282.0x00012b +# It says there was no real standard in Bahrain before 1941-07-20. +# +0330 was used by steamers of the British India Co, by Petroleum Concessions +# and by Cable & Wireless; +0323 was used by the Eastern Bank Ltd, BOAC, and +# Bahrein Petroleum (Bapco), and California Arabian Standard Oil Co (Casoc) +# adopted DST effective 1941-05-24. Alban suggested adopting DST, R.B. Coomb +# of C&W countersuggested +0330, and although C.A. Rodstrom of Casoc (formerly +# of Bapco) stated that Bahrain had formerly used +0330 before Bapco arrived +# but Bapco switched to +0323 because of "constant confusion", the consensus +# was +0330. The government adopted +0330 in 1941-07-20 and companies seem to +# have switched by 08-01. No time of day was given for the 1940s transitions. Zone Asia/Bahrain 3:22:20 - LMT 1941 Jul 20 # Manamah 3:30 - +0330 1944 Jan 1 4:00 - +04 1972 Jun -- 2.17.1

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Re: [tz] A warning on the tzdb 2020a
by Paul Eggert July 9, 2020

July 9, 2020

On 7/8/20 2:22 PM, Matias Fonzo wrote: > ./zic -d '/usr/src/qi/build/package-tzdb/etc/zoneinfo-leaps' -L leapseconds > tzdata.zi > warning: "leapseconds", line 79: "#expires" is obsolescent; use "Expires" Yes, that's a known warning. You can silence the warning by removing the leapseconds file and then building with 'make EXPIRES_LINE=1'. See the Makefile for details. At some point in the not-too-distant future I plan to fix this by defaulting EXPIRES_LINE=1 in the Makefile; this will change the "#Expires" line to an "Expires" line in the distributed leapseconds file. In reviewing the EXPIRES_LINE=1 code I noticed that it put a wrong comment in its output, which I fixed by installing the attached. I also updated the expires line as noted in <https://mm.icann.org/pipermail/tz/2020-July/029165.html>.

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[PATCH] No leap second on 2020-12-31
by Paul Eggert July 9, 2020

July 9, 2020

* leap-seconds.list: Update file from NIST, retrieved from ftp://ftp.nist.gov/pub/time/leap-seconds.list in ASCII mode. --- leap-seconds.list | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/leap-seconds.list b/leap-seconds.list index ac153da..e897a86 100644 --- a/leap-seconds.list +++ b/leap-seconds.list @@ -204,10 +204,10 @@ # current -- the update time stamp, the data and the name of the file # will not change. # -# Updated through IERS Bulletin C59 -# File expires on: 28 December 2020 +# Updated through IERS Bulletin C60 +# File expires on: 28 June 2021 # -#@ 3818102400 +#@ 3833827200 # 2272060800 10 # 1 Jan 1972 2287785600 11 # 1 Jul 1972 @@ -252,4 +252,4 @@ # the hash line is also ignored in the # computation. # -#h a1c168ae 27c79a7d 9dddcfc3 bcfe616b 2e2c44ea +#h 064356a8 39268b92 76e4d5ef 3e22fae1 0cca529c -- 2.17.1

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Tim Parenti as backup TZ Coordinator?
by Paul Eggert July 9, 2020

July 9, 2020

Tim Parenti's recent emails to the list reminded me that I'd long been meaning to nominate him to be my backup as TZ Coordinator. We should have a backup in case I am no longer available due to retirement or whatever, not that I'm planning to retire any time soon. I would like to start by giving him commit privileges to the development repository on GitHub, so that his contributions can become part of releases more easily. Tim has been a longtime and substantial contributor to tzdb, as evidenced by his detailed and careful patches. Although he's mostly worked in the tzdata area, he's also proficient on the code side, as his recent patch proposals demonstrate. He and I have corresponded by email about this and he's indicated his willingness to take on the responsibility. I'd appreciate reactions to Tim's offer to be backup; please respond within the next week.

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North Vietnam 1970 to 1975 - Asia/Hanoi belongs into main file
by Alois Treindl July 2, 2020

July 2, 2020

(Corrected subject line) The backzone file contains the zone Asia/Hanoi It should go into the main file for Asia. There exists no doubt that in all of what was North Vietnam between at least 1970 and 1975 the timezone was 7h east, and not 8h east as in South Vietnam. There may be unclear borders, but most of North Vietnam, including its capital, was not unclear at all. I find it a discrimination of former North Vietnam to not have it represented correctly, at least for the post-1970 period. What Paul Eggert writes in the comments is a poor excuse. From Paul Eggert (2019-02-19): # # The Ho Chi Minh entry suffices for most purposes as it agrees with all of # Vietnam since 1975-06-13. Presumably clocks often changed in south Vietnam # in the early 1970s as locations changed hands during the war; however the # details are unknown and would likely be too voluminous for this database. # # For timestamps in north Vietnam back to 1970 (the tzdb cutoff), # use Asia/Bangkok; see the VN entries in the file zone1970.tab. # For timestamps before 1970, see Asia/Hanoi in the file 'backzone'.

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Re: [tz] Mirmalek on Martian timekeeping
by Paul Eggert June 30, 2020

June 30, 2020

On 6/30/20 2:00 AM, BASTIAN Michelle wrote: > I wondered if you had come across this ethnography of mars working time https://brill.com/view/journals/kron/8/2/article-p159_7.xml?language=en No, I wasn't familiar with Mirmalek's work. I see she turned it into a book published in March. Thanks for the heads-up. I updated theory.html's discussion of Martian timekeeping based on the info you sent, and installed the attached patch. This patch also changes some tenses in the text, as the Mars Exploration Rover mission's second rover bit the dust in 2018 (literally: communications cut off during a planetwide dust storm).

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re SPDX, I'll do the work, if you'll use the tag
by Mark Atwood June 30, 2020

June 30, 2020

I was tagged in to this list because of the discussion about SPDX license tagging. I sit on the SPDX committee (which doesn't mean much, it's similar to an IETF WG, in that anyone who joins the list, joins the calls, and then does needed work is "on the committee"). It may be useful to have an SPDX tag for the TZ database data files. The SPDX makes nearly zero legal assessment about a license. Applying an SPDX tag to an existing project is intended to document reality in a machine readable way, it is not intended to change reality. Having an SPDX tag is mostly for the benefit of systems and companies who are trying to be scrupulously correct when complying with open source licenses. When the SPDX evaluates a license, the things looked for are "does/will it have real users?", "does it have a stable enough text that the matching tools can correctly identify it?", and "is it for content intended for mostly uncontrolled distribution?". We very much do not get into all the arguments about "is this well defined in europe", "is this a license or a public domain declaration", "is copyright even appropriate", "copyleft is theft", etc etc etc. We don't practice law, and we don't want to dictate policy, we just id licenses for people who just want to know they are doing the right thing when using your files, and make suggestions for projects that want to write a policy about it. Looking at the TZ database history, it has a very long history with lots of contributors, its mostly just a collection of facts, it appears to be a public domain declaration, that started out kind of adhoc. Using one of the existing PD declarations in the SPDX database would not be appropriate, because of the need to get the past contributors to assent, lots of work for no value. What does make sense is creating a new tag, something like "TZ-PD". Then you can start putting "# SDPX-License-Identifier: TZ-PD" in your database text source file, and make life easier for a bunch of people who just want to do the right thing with your data. To repeat, adding that SPDX license tag of a new identifer to id an existing stable in the field declaration, like this, does not change any legal obligations or expose anyone to any new legal risks. It's just a machine readable way of saying what's already been said about the copyright status of the TZ database. So, I'm willing to volunteer to do that lift for the TZ community, if you are willing to use the resulting id tag. What say you? ..m Mark Atwood <mark.atwood(a)gmail.com> https://keybase.io/fallenpegasus +1-206-604-2198

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North Vietnam 1970 to 1970 - Asia/Hanoi belongs into main file
by Alois Treindl June 28, 2020

June 28, 2020

The backzone file contains the zone Asia/Hanoi It should go into the main file for Asia. There exists no doubt that in all of what was North Vietnam between at least 1970 and 1975 the timezone was 7h east, and not 8h east as in South Vietnam. There may be unclear borders, but most of North Vietnam, including its capital, was not unclear at all. I find it a discrimination of former North Vietnam to not have it represented correctly, at least for the post-1970 period. What Paul Eggert writes in the comments is a poor excuse. From Paul Eggert (2019-02-19): # # The Ho Chi Minh entry suffices for most purposes as it agrees with all of # Vietnam since 1975-06-13. Presumably clocks often changed in south Vietnam # in the early 1970s as locations changed hands during the war; however the # details are unknown and would likely be too voluminous for this database. # # For timestamps in north Vietnam back to 1970 (the tzdb cutoff), # use Asia/Bangkok; see the VN entries in the file zone1970.tab. # For timestamps before 1970, see Asia/Hanoi in the file 'backzone'.

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Use or Apply for SPDX Licence
by Brian Inglis June 23, 2020

June 23, 2020

Hi folks, It would be useful to distributions, packagers, and organization licence checkers if the tzcode and tzdata were covered by (a) Public Domain SPDX licence identifier(s) https://spdx.org/licenses/ e.g. CC-PDDC, PDDL, SAX-PD, Unlicense, WTFPL, etc. or applied for it's own e.g. IANA-TZ-PD. -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised. [Data in IEC units and prefixes, physical quantities in SI.]

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[PROPOSED] zic now defaults to ‘-b slim’
by Paul Eggert June 21, 2020

June 21, 2020

Make zic’s ‘-b slim’ option the default. This option first appeared in tzdb 2019b (2019-07-01), and is already the default in NetBSD 9.0 (2020-02-14) and seems to be working there. Using slim format should help finish off the TZif format’s Y2038 transition that began in tzcode 95f (1995-10-28). * Makefile, NEWS, zic.8: Mention this. * zic.c (ZIC_BLOAT_DEFAULT): Default to "slim". --- Makefile | 10 +++++----- NEWS | 2 ++ zic.8 | 10 ++++------ zic.c | 5 ++--- 4 files changed, 13 insertions(+), 14 deletions(-) diff --git a/Makefile b/Makefile index 0da7c3f..8abd4d0 100644 --- a/Makefile +++ b/Makefile @@ -22,6 +22,7 @@ BUGEMAIL= tz(a)iana.org # DATAFORM= main # To wait even longer for new features, use: # DATAFORM= rearguard +# Rearguard users might also want "ZFLAGS = -b fat"; see below. DATAFORM= main # Change the line below for your timezone (after finding the one you want in @@ -249,13 +250,12 @@ LDLIBS= # other than simply getting garbage data # -DUSE_LTZ=0 to build zdump with the system time zone library # Also set TZDOBJS=zdump.o and CHECK_TIME_T_ALTERNATIVES= below. -# -DZIC_BLOAT_DEFAULT=\"slim\" to default zic's -b option to "slim", and -# similarly for "fat". Fat TZif files work around incompatibilities +# -DZIC_BLOAT_DEFAULT=\"fat\" to default zic's -b option to "fat", and +# similarly for "slim". Fat TZif files work around incompatibilities # and bugs in some TZif readers, notably readers that mishandle 64-bit # data in TZif files. Slim TZif files are more efficient and do not # work around these incompatibilities and bugs. If not given, the -# current default is "fat" but this is intended to change as readers -# requiring fat files often mishandle timestamps after 2037 anyway. +# default is "slim". # -DZIC_MAX_ABBR_LEN_WO_WARN=3 # (or some other number) to set the maximum time zone abbreviation length # that zic will accept without a warning (the default is 6) @@ -390,7 +390,7 @@ ZIC= $(zic) $(ZFLAGS) # To shrink the size of installed TZif files, # append "-r @N" to omit data before N-seconds-after-the-Epoch. -# You can also append "-b slim" if that is not already the default; +# To grow the files and work around older application bugs, append "-b fat"; # see ZIC_BLOAT_DEFAULT above. # See the zic man page for more about -b and -r. ZFLAGS= diff --git a/NEWS b/NEWS index bfe02ea..6b9fd43 100644 --- a/NEWS +++ b/NEWS @@ -23,6 +23,8 @@ Unreleased, experimental changes Changes to code + zic now defaults to '-b slim' instead of to '-b fat'. + zic's new '-l -' and '-p -' options uninstall any existing localtime and posixrules files, respectively. diff --git a/zic.8 b/zic.8 index a431311..8d34368 100644 --- a/zic.8 +++ b/zic.8 @@ -61,15 +61,13 @@ is .BR slim , keep the output files small; this can help check for the bugs and incompatibilities. -Although the default is currently -.BR fat , -this is intended to change in future -.B zic -versions, as software that mishandles the 64-bit data typically +The default is +.BR slim , +as software that mishandles 64-bit data typically mishandles timestamps after the year 2038 anyway. Also see the .B \*-r -option for another way to shrink output size. +option for another way to alter output size. .TP .BI "\*-d " directory Create time conversion information files in the named directory rather than diff --git a/zic.c b/zic.c index c874b04..3aed819 100644 --- a/zic.c +++ b/zic.c @@ -661,8 +661,7 @@ static const char * tzdefault; static const char * yitcommand; /* -1 if the TZif output file should be slim, 0 if default, 1 if the - output should be fat for backward compatibility. Currently the - default is fat, although this may change. */ + output should be fat for backward compatibility. The default is slim. */ static int bloat; static bool @@ -672,7 +671,7 @@ want_bloat(void) } #ifndef ZIC_BLOAT_DEFAULT -# define ZIC_BLOAT_DEFAULT "fat" +# define ZIC_BLOAT_DEFAULT "slim" #endif int -- 2.17.1

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Sudan/Khartoum time zone
by Ubay Abdelgadir June 21, 2020

June 21, 2020

Dears at IANA, Khartoum's time zone is +2 since 1/Nov/2017. I think it is wrong in the IANA database: Zone Africa/Khartoum 2:10:08 - LMT 1931 2:00 Sudan CA%sT 2000 Jan 15 12:00 3:00 - EAT 2017 Nov 1 2:00 - CAT BR Ubay Abdelgadir

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Formal models and the need for storing original source data
by Michael Kenniston June 21, 2020

June 21, 2020

> > ---------- Forwarded message ---------- > From: Robert Elz <kre(a)munnari.oz.au> > To: Lester Caine <lester(a)lsces.uk> > Cc: tz(a)iana.org > Bcc: > Date: Wed, 03 Jun 2020 19:31:43 +0700 > Subject: Re: [tz] How good is pre-1970 time zone history represented in TZ > database? > Date: Wed, 3 Jun 2020 12:22:32 +0100 > From: Lester Caine <lester(a)lsces.uk> > Message-ID: <3576438c-e0bd-7188-2153-43d80e9054b8(a)lsces.uk> > > There are two kinds of > changes that may be made to a zone. One affects only future timestamps, > and is the common old garden variety "government interference" or however > you think of it. These are far and away the most common changes. While > when we have insufficient notification of a change, it may be applied > retrospectively, when that has happened, everyone tends to be very aware > that there were bad time conversions for a while. In any case, old > historic stored data isn't affected at all by this kind of change, it > is as valid (or not) after the change as it was before. > You can also have data recorded in the past which refers to the future, so even a change that affects only future timestamps can still invalidate existing stored data. > The second kind of change is a correction to historic data. This happens > when > we discover an error in what was present (and these days, almost only ever > affects pre-1970 timestamps). > > In those, if someone had stored the UTC converted form of some local > timestamp, > then after the correction they wouldn't get back the data that was > originally > used to produce it. > > The problem there is having discarded the original data instead of > retaining > it. Always retain the original source data. Then by all means, when > computing, convert timestamps from their various local values to UTC so > they can be more easily correctly ordered (or whatever) but use those > converted values only for transient computations. Store the original. > Always. > > If that is done correctly, then after a correction to old data, the > results might be different than they were before - but that's only because > they were wrong before, and (hopefully) better after the fix. > I agree 100%. I've been struggling for years to really get my head wrapped around this stuff, and finally decided to create a formal model using abstract data types. I'm finding that approach to be quite helpful, so I wrote it up in a couple of essays that folks on this list might find interesting. In fact, the folks on this list may well be the *only* people who would find them interesting. :-) The first is aimed at the general programmer, but it introduces the fundamental concepts: https://drive.google.com/file/d/1WntAyhIawYtbL2k3fPE71cM9EFkVCJGQ/view?usp=… The second is aimed at time geeks and goes much deeper into the underlying theory: https://drive.google.com/file/d/1aOj9YeDFUST0lQFXZiUsCSmxjnzlbIe4/view?usp=… These are still in draft form, but I hope others find some value in them. (Teaser: the model makes no reference to years, days, hours, or seconds. How's that for abstract?) What is rather interesting (and reassuring) is that the formal model ends up telling us pretty much what this thread has been saying: store original data. However, by looking at things in terms of abstract data types, you can easily see *why* you need to do that without having to resort to specific examples, and many seemingly unrelated cases can be seen to be special cases of the same underlying phenomenon. The model also points you to the very specific places in your design and code where you have to watch out for problems. > The only time it makes sense to store timestamps in other than the original > form is when we *know* that the conversion is correct (and hence, no later > correction will change it). For users of tzdata that really only applies > to post-1970 timestamps. > When exactly do we *know* anything, I mean really for sure? Imagine yourself back in 1966. UTC has been chugging along nicely for five years, providing a well-behaved predictable time standard. We know it's never going to change. Now it's 1967. Oops, the name just changed. Well, that doesn't really count, a rose by any other name ... Now it's 1972. Oops again, we just added a leap second, and there are more on the way. Sorry unix time_t, your fundamental assumption was just revoked -- and so for the next 50 years, nearly every computer on the planet will stubbornly refuse to accept the existence of leap seconds. Never say never. > ---------- Forwarded message ---------- > From: Robert Elz <kre(a)munnari.oz.au> > To: Lester Caine <lester(a)lsces.uk> > Cc: tz(a)iana.org > Bcc: > Date: Wed, 03 Jun 2020 23:48:42 +0700 > Subject: Re: [tz] How good is pre-1970 time zone history represented in TZ > database? > Date: Wed, 3 Jun 2020 16:02:45 +0100 > From: Lester Caine <lester(a)lsces.uk> > Message-ID: <3b7f0c78-4dd7-0f2e-a8e3-2b24401e7e1c(a)lsces.uk> > > | I came into this 20 years ago > > I've been involved with it for longer than that - back to my first > unix experience, in '76, where the US tz rules were compiled into the > code, and most people in AU simply adjusted their computer's clock > (their offset from UTC) 4 times a year (when the US switched summer time > on and off, and when AU did - and yes, that meant that the generated GMT > timestamps were wrong, most of the time). From that (a bit later) I was > responsible for the mess that existed until ado invented tzdata (and yes, > I mean the 2nd arg to gettimeofday()). > You make me look like a newbie. I first got into this seriously in 1997 while updating legacy systems to handle Y2K. > >From all of this I have learned that time is hard. Really hard. > > Many people believe that since they learned to tell the time when > they were 4 or 5 years old, and have been doing it ever since, they > know all there is to know. That's sad... > See the discussion of seduction and polar bears in the first essay linked above. > | now while working with a data archive > | which has now been simply dumped because we had no idea what rules were > | used to produce the normalised data. > > That's a pity, byt sometimes past mistakes simply come back to bite, > and sometimes bite hard. Note that the error there was normalising the > data, if that hadn't been done, none of the rest of it would matter, > you'd now have the original data and could manipulate it however seems > best, for now, regardless of what anyone did with it decades ago (and if > you get it all wrong, future generations could cope, because they'd also > still have the original data, and can fix any errors). > > | Nowadays yes it does make sense to > | store both an original time and a normalised time, > > No, it doesn't, just the original, plus ... > > | along with a location, > > yes, something which can be mapped into a timezone - and as accurate > a location as possible. > > | and a record of which version of rules was used to do the > | normalization. > > Don't care about that, since the result won't be being saved. > > | Add to that a flag that indicates if the UTC time is fixed! > > If the UTC time is the authoritative one, that is what is stored. > No need for extra flags. Just the authoritative time - the one > which defines whatever it is that is being recorded. > I second everything Robert Elz said here. - Michael Kenniston

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[PROPOSED 1/2] zic has new ‘-l -’ and ‘-p -’ options
by Paul Eggert June 13, 2020

June 13, 2020

* NEWS, zic.8: Mention this. * zic.c (dolink): If fromfield is "-", simply remove tofield. --- NEWS | 3 +++ zic.8 | 12 ++++++++++++ zic.c | 5 ++++- 3 files changed, 19 insertions(+), 1 deletion(-) diff --git a/NEWS b/NEWS index 3bcddd0..cdcdbc1 100644 --- a/NEWS +++ b/NEWS @@ -23,6 +23,9 @@ Unreleased, experimental changes Changes to code + zic's new '-l -' and '-p -' options uninstall any existing + localtime and posixrules files, respectively. + The undocumented and ineffective tzsetwall function has been removed. diff --git a/zic.8 b/zic.8 index b1bf437..a431311 100644 --- a/zic.8 +++ b/zic.8 @@ -85,6 +85,12 @@ will act as if the input contained a link line of the form .ti +.5i .ta \w'Link\0\0'u +\w'\fItimezone\fP\0\0'u Link \fItimezone\fP localtime +.sp +If +.I timezone +is +.BR \*- , +any already-existing link is removed. .TP .BI "\*-L " leapsecondfilename Read leap second information from the file with the given name. @@ -109,6 +115,12 @@ and it should not be combined with if .IR timezone 's transitions are at standard time or Universal Time (UT) instead of local time. +.sp +If +.I timezone +is +.BR \*- , +any already-existing link is removed. .TP .BR "\*-r " "[\fB@\fP\fIlo\fP][\fB/@\fP\fIhi\fP]" Reduce the size of output files by limiting their applicability diff --git a/zic.c b/zic.c index 2875b55..c874b04 100644 --- a/zic.c +++ b/zic.c @@ -981,6 +981,7 @@ hardlinkerr(char const *from, char const *to) static void dolink(char const *fromfield, char const *tofield, bool staysymlink) { + bool remove_only = strcmp(fromfield, "-") == 0; bool todirs_made = false; int link_errno; @@ -988,7 +989,7 @@ dolink(char const *fromfield, char const *tofield, bool staysymlink) ** We get to be careful here since ** there's a fair chance of root running us. */ - if (itsdir(fromfield)) { + if (!remove_only && itsdir(fromfield)) { fprintf(stderr, _("%s: link from %s/%s failed: %s\n"), progname, directory, fromfield, strerror(EPERM)); exit(EXIT_FAILURE); @@ -1003,6 +1004,8 @@ dolink(char const *fromfield, char const *tofield, bool staysymlink) progname, directory, tofield, e); exit(EXIT_FAILURE); } + if (remove_only) + return; link_errno = staysymlink ? ENOTSUP : hardlinkerr(fromfield, tofield); if (link_errno == ENOENT && !todirs_made) { mkdirs(tofield, true); -- 2.17.1

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