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Re: [tz] On ISO country for timezones (Re: Classifying IDs)
by dpatte Oct. 7, 2021

Oct. 7, 2021

I believe you are missing an important part of this discussion.There is a strong need for a repository of pre 1970 data, especially for historical research applications. As this is the only tz database, tz has also become the main database for this older data.For any populated place on earth researchers need such a repository. If I want to add the pre 1970 tz history for Ottawa Canada where should it be stored? Since it is called tz, and it also has other pre 1970 data, tz seems the appropriate place.But if no simple method of adding open-ended historical data is negotiated here, then the only other option is to fork tz and work on it as a separate project.Secondly, since the number of locations that could eventually be supported in a historical tz database is potentially very large, it cannot not be micromanaged, and this suggests that each historical zone should use an international standard for naming - iso - for simplicity and clarity.Canada/Ontario/OttawaAre we going to have two tz databases, or just one. That is the question here.Sent from my Galaxy -------- Original message --------From: Steffen Nurpmeso via tz <tz(a)iana.org> Date: 2021-10-07 09:35 (GMT-05:00) To: Stephen Colebourne <scolebourne(a)joda.org> Cc: tz(a)iana.org Subject: Re: [tz] On ISO country for timezones (Re: Classifying IDs) Stephen Colebourne wrote in <CACzrW9Cau-q2e+yoBcg=7Rztu19zZN582Xca9ZMYbz=H_0iOpw(a)mail.gmail.com>: |On Thu, 7 Oct 2021 at 07:08, Watson Ladd via tz <tz(a)iana.org> wrote: ... |I agree with backwards compatibility. The primary concern here is |whether an ID is considered deprecated or not.IDs shall be stable and not change at all. At maximum they shouldbe moved to backward, for example if a zone is renamed (which mayhappen for example for Ukraine in a not too distant future, ifthat is still necessary then, and it looks as if it would be).I would always have been all for making infinite stability of IDsa documented assertion.Even if not, your "six months" claim is nothing but an aggressivestatement. I think this entire thread is shadowboxing and noisefor nothing.Looking at the interface of your JAVA framework i think getID()should simply return the correct ID, which may be a link if it isone, and just in case this is not what getID() already returns.In my opinion there are only two problems with IANA TZ and howPaul Eggert manages it as a maintainer. That is the same PaulEggert who contributes to this software since 1995, an astonishing26 years. Corroding the maintainership with a continuous streamof noise is disgusting.The first is combining of datasets to equal-post-1970 bundles,which is going on for many years. But the data is there, it is inbackzone, and everybody can easily install a complete TZ DB onone's own request. Yet noone did, even though many packagers areon this list. This is schizophrenic. But maybe it is onlybecause of black and yellow people do not matter as much as someblue-eyed white people from northern Europe, which does not trulycome as a surprise given the audience who possibly reads this now,and given the fact that colonianisation ended only about 55 yearsago, and de facto was only turned from armed political to armedmaterial oppression.The second is that documentation did not follow suit the codeimprovements, as has been recently shown for tzselect(8) and the-t option. That tzselect(8) uses the administrative zone1970.taband not the end-user-preferrable zone.tab is a different thing.If you want to enforce upon the maintainer of the TZ database thatthe pre-1970 data is joined back into the normal data, or that"backzone" is splitted into "backzone" and "unreliable", and/orthat "backzone" is included by default, and/or that "ZFLAGS='-r@0'" is made default, then create a thread and try to gain enoughhums, but please stop this subversion by spreading uncertainty andthat even upon topics which never were under discussion as far asi know, and i also read this list for a decade now.It must anyway be said it was nicer once i only had thedistribution and did not know about the list :)Ciao from Germany,--steffen||Der Kragenbaer, The moon bear,|der holt sich munter he cheerfully and one by one|einen nach dem anderen runter wa.ks himself off|(By Robert Gernhardt)

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TZDB use cases
by Stephen Colebourne Oct. 7, 2021

Oct. 7, 2021

In this thread I want to try and capture the *requirements* for the project from the perspective of a downstream user. Given this, we may then have a chance to analyse whether the project needs a change of rules. NOTE: The discussion below is not a proposal, nor does it seek to explore which locations get pre-1970 data. Lets keep that for another thread. -------- 1) "What is the time now?" To answer this question you need a dataset that records the current timezone rules for each region in the world. Over time that data will naturally build up to form a historic record. To aid the project, a 1970 rule has been adopted for data management. In some parts of the world, clocks have agreed since 1970 across large parts of a continent. In other parts of the world, different parts of the same country have had different rules since 1970. Viewing the data through a post-1970 lens splits the planet into regions where clocks have agreed since 1970. Some of these regions are quite abstract, for example the region including Iceland, Ivory Coast, and St Helena. An abstract region would need to be split if one of the parts of the region changed its timezone rules. If a user had previously selected to follow one of these abstract regions, they might have to change their timezone settings. For example, if a user in Iceland selected their abstract region by the recommended ID based on the largest city they would get `Africa/Abidjan`, but if the Ivory Coast changed their rules, users in Iceland would have to change their selected timezone. The minimum set of IDs is one ID for each abstract region. The current ID scheme selects the largest city in the abstract region. My interpretation: * An abstract region should theoretically have an ID separate to the IDs of the cities/countries in the region * Trying the ID of the abstract region to the largest city in the region is prone to failure if that city changes timezone rules but the rest of the abstract region stays the same. * An abstract region ID would naturally have no pre-1970 data, as it doesn't define data in a single city/location. * The alternative is to encourage users to use their local city, which means that IDs like Europe/Amsterdam and Europe/Oslo cannot be deprecated -------- 2) "What was the time at some instant in the past?" The project can answer this question pretty reliably for dates from 1970 onwards because of the data set in #1. The project can never realistically answer the question reliably or accurately before 1970 for *all* locations. For example, timezone rules were entirely local in the US for about 20 years, meaning that hundreds of entries would be needed to correctly capture the data. In addition, much of the historic data globally is unknown and not viable to research, even if someone wanted to do so. It is possible to research and record historic timezone rules for *some* locations. Europe/London being one example. The project generally operates on the basis that if an ID exists, historical data can be recorded against it, although which file that data lives in has varied over time. IDs are generally not created solely to document historic data. There is no minimum set of IDs for this use case - the set of possible IDs is unbounded. My interpretation: * The majority of pre-1970 data isn't much use * Some pre-1970 data is high quality, and almost certainly relied upon (eg Europe/London) * Without a massive increase in scope the best that can be done pre-1970 is to record data against IDs created for some other reason. -------- 3) "An event will happen at this time in the future" If an end-user wants to store an event in the future, eg. a one hour meeting next month, the correct approach is to store the date, time and zone ID, not the offset (which is not yet known for certain).Even if the local timezone authority changes the tz rules between now and the event, the time of the event is still correct. https://stackoverflow.com/questions/19166995/java-calendar-date-and-time-ma… For this approach to work, the ID that is stored must be aligned with the timezone authority. Business contracts are frequently written to describe future events. For example, payment must be made by 2pm Paris time on a given date. The minimum set of IDs for this use case is one ID per timezone authority. This is typically the country but not necessarily, examples being decisions devolved to states/nations etc. My interpretation: * Using TZDB IDs for future events/contracts is very widespread * In most parts of the world, this requires one ID per country, in some parts of the world additional IDs would ideally be needed such as per state in the US * One ID for each ISO country (as was the guideline in the past) is a reasonable minimum expectation of end users * While one might argue IDs for future events are not TZDBs problem, I believe the reality is that they are because usage in this way is already very widespread -------- 4) "An event will happen at this time in the future relative to a shared/common definition" Some future events are declared relative to a definition that is supra-national or federal. For example, US Mountain, US Pacific, EU Central etc. A TV show might be defined to air at 8pm Mountain Time in one months time. It will air at that time regardless of whether any of the states that are currently on Mountain Time change to Pacific Time. For example, even if Denver (and Colorado) moved to Pacific Time or stopped following DST, Mountain Time would still exist and the TV show would still air at 8pm Mountain. The minimum set of IDs for this use case is one ID per shared/common definition. These IDs are not full aliases for a country or city ID, although they may currently share data. To support this use case, these IDs cannot be deprecated. My interpretation: * Some shared zone IDs are distinct and separate enough to warrant a full ID * US Mountain time is not the same as Denver time when considering the future, the IDs could diverge * In TZDB terms, the Link from US/Mountain to America/Denver is fine to define the data, but US/Mountain should not be considered deprecated as it has a real and distinct meaning separate from America/Denver * It would be useful to agree what the criteria for including these shared/federal rules is. -------- 5) "Data should be backwards compatible" The project has various associated downstream projects. Many of these have an expectation of backwards compatibility. This compatibility extends to the binary format, the source format, and the data contained within. This use case wants to see the project just continue with the data it has, enhancing it over time. The project has a pretty good record in terms of not removing IDs. For example, IDs exist for "Portugal" and "Poland", but not "Italy" or "Spain" simply because they were defined once upon a time. My understanding is that IDs in the `backward` file represent deprecated IDs that should not be used going forward. Yet, downstream projects focussed on backwards compatibility will generally use the `backward` file in full. The minimum set of IDs for this use case is the set of IDs that existed in the previous release. My interpretation: * Many users care about compatibility * The current IDs are not going away * Inconsistency has existed in TZDB for many years, see "Portugal" vs "Spain" - no one wants to fix that * It is hard at present to identify IDs that are deprecated because of proper aliasing, such as spelling changes, vs those where the ID is a real location but its TZDB status has been reduced. * Change may be possible with a long notice period --------- Please note that the above is not a proposal, but an exploration of the design space. If you have any use cases I've missed feel free to write them up. thanks Stephen

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timezone Verschlimmbesserung
by Tony Finch Oct. 6, 2021

Oct. 6, 2021

Paul Eggert's rationale is informative https://mm.icann.org/pipermail/tz/2021-September/030764.html But I think there are a few more things to say. The aim of merging timezones was to avoid political issues and to reduce the maintenance burden. It seems to me that it has failed to achieve those goals. There have been several very long discussions on the topic, and the recent arguments are making exactly the same points as were made in 2013. So I think the changes have increased the amount of political discussion and controversy on the tz list, not reduced it. https://mm.icann.org/pipermail/tz/2013-May/thread.html https://mm.icann.org/pipermail/tz/2013-August/thread.html https://mm.icann.org/pipermail/tz/2013-September/thread.html Paul says in his rationale that it was a lot of extra work, and in other messages he said that he has found it hard to keep up with the discussions. So merging timezones has increased the maintenance burden, not reduced it. I have identified two policy changes that caused this argument. In 2013, Paul Eggert started a new policy of merging timezones that are the same since 1970. As far as I can tell, no-one wanted this other than Paul. This merging policy was applied first to places with small populations, and (because of alphabetical order) to Africa, which is not well-represented by the people on the TZ list. Some of the merges also ignored the guideline that each country should have at least one timezone to call its own. The other policy change was to drop the guideline that each country should have at least one timezone. This change occurred in 2019, buried at the end of a very long discussion about Vietnam, and presented as a fait accompli. https://mm.icann.org/pipermail/tz/2019-February/027602.html This was after a great deal of discussion about the need to retain country information in the tz database, back in 2013 when these changes started. As I understand it, the equity / fairness issue is that the timezone merges were implemented in an unfair manner, affecting Africa (since 2014, against the guidelines as written at the time) but not Europe. So although Paul says the merges worked without significant incident, they did in fact cause a political complaint - exactly what the merges were supposed to avoid. The current argument was triggered by the question of whether this fairness issue should be addressed by undoing the data loss in the compiled tz files that caused the complaint, or by imposing the data loss more strictly. I think the way to fix this is to revert both policy changes, and revert all the timezone merges. Tony. -- f.anthony.n.finch <dot(a)dotat.at> https://dotat.at/ Lundy, Fastnet, Irish Sea: Northwest 4 to 6, backing southwest 5 to 7, perhaps gale 8 later. Slight or moderate until later in Irish Sea and Lundy, otherwise moderate or rough. Rain or showers. Good, occasionally poor.

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Italy April 1944 discrepancy between comment and data
by Alois Treindl Oct. 5, 2021

Oct. 5, 2021

For Italy in 1944 zone Europe/Rome there is a discrepancy between the comment and the data. comment: # From Paul Eggert (2016-10-27): # Go with INRiM for DST rules, except as corrected by Inglis for 1944 # for the Kingdom of Italy. This is consistent with Renzo Baldini. # Model Rome's occupation by using C-Eur rules from 1943-09-10 # to 1944-06-04; although Rome was an open city during this period, it # was effectively controlled by Germany. Data for Italy is Rule Italy 1944 only - Apr 2 2:00s 1:00 S Data for C-Eur is: Rule C-Eur 1944 1945 - Apr Mon>=1 2:00s 1:00 S where Mon>=1 in 1944 is April 3. So Rome is NOT following C-Eur. I think the rule for Itay is right, only the comment is misleading.

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legal status of information on TZ database
by nadir altinbas Oct. 5, 2021

Oct. 5, 2021

Hye, Is there a RFC document in which "explain rights and responsibilities of icann TZ coordination , about to solve regulation problems become from legal conflicts that third party person or company got and use of changes on TZ database country data by damage of their economic contracts agreement ?04.10.2021regards, Nadir Altinbasnadiraltinbas(a)yahoo.com n.altinbas

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Re: [tz] TZDB use cases
by Hal Murray Oct. 5, 2021

Oct. 5, 2021

Stephen Colebourne said: > So, it turns out that there is, I believe, a critical difference here between > the US view of timezones and the European one. In the US, timezones do not > follow the boundary of the whole country, nor even States. In Europe, by > contrast, timezone boundaries are very much driven by country boundaries. There is another interesting difference. US borders are stable. Czechoslovakia and Yugoslavia have split post 1970. Did all the pieces retain the same TZ info? I think small regions on the France/German border changed sides after WW 1. Are there others? Anything similar post 1970? Have any US/state borders changed when rivers changed their course? If so, do any people live in the regions that changed and/or did anything interesting happen there? -- These are my opinions. I hate spam.

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32-bit section missing transitions in 2021b
by Daniel Fischer Oct. 2, 2021

Oct. 2, 2021

Hi, It looks like 32-bit data generated by 2021b is missing the effects of transitions below INT32_MIN. Before commit 93132d18, zones had a transition at INT32_MIN to the type in use at that time. For example, the Pacific/Port_Moresby zone used to have these two transitions: -2147483648 -> 1 (+10) 2147483647 -> 1 (+10) Starting with commit 93132d18, including in 2021b, only one transition is present: 2147483647 -> 1 (+10) Since clients are supposed to assume type 0 before the earliest transition, this almost always leads to wrong times for some period of time (or all times for extreme cases like Port Moresby). Danny -- Daniel Fischer Rastatt, Germany Oracle Global Services Germany GmbH

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[tz-announce] 2021c release of tz code and data available
by Paul Eggert via tz-announce Oct. 1, 2021

Oct. 1, 2021

The 2021c release of the tz code and data is available. This is a bugfix release that addresses compatibility problems reported since 2021b came out, notably those reported by Stephen Colebourne. Although this release doesn't address the deeper issues about maintenance philosophy and procedures (discussion of which is ongoing), it does merge in changes to address what Stephen reported was his primary problem with 2021b. This release reflects the following changes, which were either circulated on the tz mailing list or are relatively minor technical or administrative changes: Briefly: Revert most 2021b changes to 'backward'. Fix 'zic -b fat' bug in pre-1970 32-bit data. Fix two Link line typos. Distribute SECURITY file. This release is intended as a bugfix release, to fix compatibility problems and typos reported since 2021b was released. Changes to Link directives Revert almost all of 2021b's changes to the 'backward' file, by moving Link directives back to where they were in 2021a. Although 'zic' doesn't care which source file contains a Link directive, some downstream uses ran into trouble with the move. (Problem reported by Stephen Colebourne for Joda-Time.) Fix typo that linked Atlantic/Jan_Mayen to the wrong location (problem reported by Chris Walton). Fix 'backzone' typo that linked America/Virgin to the wrong location (problem reported by Michael Deckers). Changes to code Fix a bug in 'zic -b fat' that caused old timestamps to be mishandled in 32-bit-only readers (problem reported by Daniel Fischer). Changes to documentation Distribute the SECURITY file (problem reported by Andreas Radke). Here are links to the release files: https://www.iana.org/time-zones/repository/releases/tzcode2021c.tar.gz https://www.iana.org/time-zones/repository/releases/tzdata2021c.tar.gz https://www.iana.org/time-zones/repository/releases/tzdb-2021c.tar.lz The following convenience links are also available, although they may point to the previous release until the relevant caches are refreshed: https://www.iana.org/time-zones/repository/tzcode-latest.tar.gz https://www.iana.org/time-zones/repository/tzdata-latest.tar.gz https://www.iana.org/time-zones/repository/tzdb-latest.tar.lz Links are also available via plain HTTP, and via FTP from ftp://ftp.iana.org/tz/releases with the same basenames as above. Each release file has a GPG signature, which can be retrieved by appending ".asc" to the above URLs. Copies of these signatures are appended to this message. This release corresponds to commit d2c79c4bc68c02b785990a6d4eb161770058078e dated 2021-10-01 14:21:49 -0700 and tagged '2021c' in the development GitHub repository at <https://github.com/eggert/tz>. Here are the SHA-512 checksums for the release files: 9ed7677744058c58656b47d77d464bad6ef503f2892b53c6abe694e68e73fa123dfc5c11bbcbbb7798f0a6bf1da72b81f8f1c63670839b967e15e58d6d36adad tzcode2021c.tar.gz e8de3a17c38f530b2ec39605699742dd32da5ee92ecf64accaaa5b012a1dac51d1f594adc52660602c3425016520346ab6ad614fa475eb310e17ccdcae93e6ca tzdata2021c.tar.gz a6a86b5b84353c952eec6192222f95f348900dfb414f2dd205fa245515a0f240ba50eab83999f2a5c2cc8e3547406c111aacd96ff9043364d679c86a5e4b0794 tzdb-2021c.tar.lz Here are the GPG digital signatures for the release files: -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmFXfJgACgkQ7ZfpDmKq fjReHA/+LiurpLRdXhwkSuhwUKlAQTKmry3F2/zFyobqi+EEEd7naiJIiQbIlScv aZ0cr6Tpq+oP0L8K0EaLMnz9vvb4qd7M3LLGOcrsML8/z0IigMBaA4c8L/Ep3ACa nsLTKESq6bYUJ2SbaFcCFx4KqwA8UEmfhzrPbNxeb3SVgrI1KwUWkpuTCOpewu+g ZYCVO7mFRhLuaD3wCbErtw9g7vQHyHGPGfTDHyc6lPrEbIaY1gwgl6GwBTmJD72a przvxg/0r0X+ZzHH9GZRQaWSDEGXYUdnIwrnS7zwDNk33WO3VwgLWiX2QMGJwiTe wPku4mnGkRhwQLzG+kJxpWe3DJ9/iKFVvxvS3/5RSN1mnELA6xcGOWMTL9cawlwo RkpyN3bLow/9u3wcW2QSrDhCTlGl5kUeK7Qbi20Rji9q2NIO0zrJ732pdr0PgyCN NeuO0YnHUW0bvGO7IMv0JfhQ+VbjB9yAzOg7D2bR2dSVm++38bR8umI757xU/6sT /CTIpmfP67FsXmtg98PbO6rEmoLr7Y/t+JYi/AwzvoHeFS5CAGs9xnTpdk+dBhjh wjLegKDtLZpIUppH9AkJ/T9MAVsfFpsLa2EnteF3LuYZhFTXzLJj3uo3l6Ji0eMZ RRy1jZAxnZ02EoLRIloezzST4pmxIurepluyzvTXVBBuXcoqDk4= =S2t+ -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmFXfJgACgkQ7ZfpDmKq fjR/9g/+LOFIZC6n1xKEMn95PsJx2e+zQ4m2/MG1L1KKZdR6kYnvQHL3hh+dXLdr cKRoB6k4AZDaCl7NZDZ8iKgm0nrXnG4/dVEfVOeJn9VHdRyYZ4sg68Nij0yHheRN fcX/ikKwmVaszwj8t+zTmetZOxlJi1mdLyZaQYgBZuM+8Aj+AnB3QUT00yP3j5xP lZgAToYXyLg8KweHnCuD41ZzU8AmsUU2GSfbTryez5lSGnhTsI+tNFtk5w+2fWZZ C0ZAskT//F2k6viFBozeBoodTs955mPKuzyWte6WyhQOTVUySuaeeAU7Dc9SK1k2 nNMTDeQyR78CL39D/X0qmINAif9YKqQ1k0fJFHH1K+pSbhtw0TaqZarQ7JRQnZpC XSIJ9PwpuLLb4k0pBUWYS+r1bZDWrymmgvDO4uNFRFC8LWR4pKyWZ8k34IYQndaV otWbBcThgyz8JJk5mrf113j7qQ3AYiC/y1lVtBpCXpOy1LzYGSTDUqUoHeib8ToD Q3wD1UTPPlo1nh47+cx/Fq1MasdB4MF/OwX7w33nV7TbYgNOHHjb5ROgf7unbaqM 96rtJDRFXFnnPtDOES3xtF4IEEXeoqx1q6AEEcEBBmkCc+DQk5AvW64JwluKn4b1 XSDP7AuXex+wJKffa/7I2KyNLNiX8aLQcnvVsD9cqV4hComR3O8= =LtLe -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmFXfJoACgkQ7ZfpDmKq fjTWQA/9Geo9i7m1YlBbU6xJQFyT2AVTTeCgA3wnQOc7VXj5Sy8/7JBU/AJW4Vmi iaTE+XZJU8ghslbdwkyEwoFcZ+4dT8qtjIDSaJ989LV8zpL0MPjgQPdYnh9egaGo qUQBXBcBzzK6giDut7vYcldf5YbK8AAv/ApvVyqL9JjdjbE2P3/juPAHUBUTxHIl bGrnRKbXIeqHB2MGgNZcby4HyblR+BCue3r9kN7Jq0kzETHG8UDeEDeHpL9x9DIq QIYpCiiuMvT7FZR4vNlQg5oBm6Tjz47BEWlvpDQcZHSAgXVrMOTds7uameG72DRW TtEGbozg2LQS3RKHn9mN0GK505d/qiSgrR/AoP420g6xa7d49Orz5qTcE4hUUqQ6 /YA2/3LqqCXeNep/BjwDvsvSTN8TKF4y0iF26Ie2BWRCnI377tT/76NncWaXRT3f k4X2qdIu/6EGle9kleanIZvet3/yavwpOXpgjcMPBwa1RoZDcH2/YSTd0uFhBXLw FTgJ2LKU1d7HVn5VR3t0z1ltjTjv5kjAt+/E/xdANN/vY27ef6yOMp9Mq4z3Pp9Y cUtwwM0aXchlCcomOhoKOShW/j8hFFlIX3pEEAQOhvDS4t7zw0x18+737Fi5diY6 5GUcyKs0sgIkGcAco1qZXd6vvR61ekq7rgMANpi8g9H5igjt5TM= =23yb -----END PGP SIGNATURE----- PS. If your tzdata parser does not yet support negative DST offsets or times past 24:00, or if it insists on a 'pacificnew' file that is no longer present, this release's data entries can be turned into a rearguard-format tarball that should work even with these older parsers. This is intended to be a temporary transition aid for these parsers. To generate a rearguard-format tarball, obtain the full distribution as described above, and run the command 'make rearguard_tarballs' on a development host. Or you can run 'make rearguard.zi' to generate a single file that can be fed directly to a parser that works like 'zic'.

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[tz-announce] 2021b release of tz code and data available
by Paul Eggert via tz-announce Oct. 1, 2021

Oct. 1, 2021

The 2021b release of the tz code and data is available. Partly because it's been so long since 2021a, this release has many changes, noted below. In one area, noted "Merge more location-based Zones" below, the mailing list has had significant trouble coming to a long-term consensus. Because we should publish something before the Samoa change takes effect, this release contains just one step towards making tzdb fairer and more equitable in future releases. This release reflects the following changes, which were either circulated on the tz mailing list or are relatively minor technical or administrative changes: Briefly: Jordan now starts DST on February's last Thursday. Samoa no longer observes DST. Merge more location-based Zones whose timestamps agree since 1970. Move some backward-compatibility links to 'backward'. Rename Pacific/Enderbury to Pacific/Kanton. Correct many pre-1993 transitions in Malawi, Portugal, etc. zic now creates each output file or link atomically. zic -L no longer omits the POSIX TZ string in its output. zic fixes for truncation and leap second table expiration. zic now follows POSIX for TZ strings using all-year DST. Fix some localtime crashes and bugs in obscure cases. zdump -v now outputs more-useful boundary cases. tzfile.5 better matches a draft successor to RFC 8536. A new file SECURITY. This release is prompted by recent announcements by Jordan and Samoa. It incorporates many other changes that had accumulated since 2021a. However, it omits most proposed changes that merged all Zones agreeing since 1970, as concerns were raised about doing too many of these changes at once. It does keeps some of these changes in the interest of making tzdb more equitable one step at a time; see "Merge more location-based Zones" below. Changes to future timestamps Jordan now starts DST on February's last Thursday. (Thanks to Steffen Thorsen.) Samoa no longer observes DST. (Thanks to Geoffrey D. Bennett.) Changes to zone name Rename Pacific/Enderbury to Pacific/Kanton. When we added Enderbury in 1993, we did not know that it is uninhabited and that Kanton (population two dozen) is the only inhabited location in that timezone. The old name is now a backward-compatility link. Changes to past timestamps Correct many pre-1993 transitions, fixing entries originally derived from Shanks, Whitman, and Mundell. The fixes include: - Barbados: standard time was introduced in 1911, not 1932; and DST was observed in 1942-1944 - Cook Islands: In 1899 they switched from east to west of GMT, celebrating Christmas for two days. They (and Niue) switched to standard time in 1952, not 1901. - Guyana: corrected LMT for Georgetown; the introduction of standard time in 1911, not 1915; and corrections to 1975 and 1992 transitions - Kanton: uninhabited before 1937-08-31 - Niue: only observed -11:20 from 1952 through 1964, then went to -11 instead of -11:30 - Portugal: DST was observed in 1950 - Tonga: corrected LMT; the introduction of standard time in 1945, not 1901; and corrections to the transition from +12:20 to +13 in 1961, not 1941 Additional fixes to entries in the 'backzone' file include: - Enderbury: inhabited only 1860/1885 and 1938-03-06/1942-02-09 - The Gambia: 1933 and 1942 transitions - Malawi: several 1911 through 1925 transitions - Sierra Leone: several 1913 through 1941 transitions, and DST was NOT observed in 1957 through 1962 (Thanks to P Chan, Michael Deckers, Alexander Krivenyshev and Alois Treindl.) Merge more location-based Zones whose timestamps agree since 1970, as pre-1970 timestamps are out of scope. This is part of a process that has been ongoing since 2013. This does not affect post-1970 timestamps, and timezone historians who build with 'make PACKRATDATA=backzone' should see no changes to pre-1970 timestamps. When merging, keep the most-populous location's data, and move data for other locations to 'backzone' with a backward link in 'backward'. For example, move America/Creston data to 'backzone' with a link in 'backward' from America/Phoenix because the two timezones' timestamps agree since 1970; this change affects some pre-1968 timestamps in America/Creston because Creston and Phoenix disagreed before 1968. The affected Zones are Africa/Accra, America/Atikokan, America/Blanc-Sablon, America/Creston, America/Curacao, America/Nassau, America/Port_of_Spain, Antarctica/DumontDUrville, and Antarctica/Syowa. Changes to maintenance procedure The new file SECURITY covers how to report security-related bugs. Several backward-compatibility links have been moved to the 'backward' file. These links, which range from Africa/Addis_Ababa to Pacific/Saipan, are only for compatibility with now-obsolete guidelines suggesting an entry for every ISO 3166 code. The intercontinental convenience links Asia/Istanbul and Europe/Nicosia have also been moved to 'backward'. Changes to code zic now creates each output file or link atomically, possibly by creating a temporary file and then renaming it. This avoids races where a TZ setting would temporarily stop working while zic was installing a replacement file or link. zic -L no longer omits the POSIX TZ string in its output. Starting with 2020a, zic -L truncated its output according to the "Expires" directive or "#expires" comment in the leapseconds file. The resulting TZif files omitted daylight saving transitions after the leap second table expired, which led to far less-accurate predictions of times after the expiry. Although future timestamps cannot be converted accurately in the presence of leap seconds, it is more accurate to convert near-future timestamps with a few seconds error than with an hour error, so zic -L no longer truncates output in this way. Instead, when zic -L is given the "Expires" directive, it now outputs the expiration by appending a no-change entry to the leap second table. Although this should work well with most TZif readers, it does not conform to Internet RFC 8536 and some pickier clients (including tzdb 2017c through 2021a) reject it, so "Expires" directives are currently disabled by default. To enable them, set the EXPIRES_LINE Makefile variable. If a TZif file uses this new feature it is marked with a new TZif version number 4, a format intended to be documented in a successor to RFC 8536. zic -L LEAPFILE -r @LO no longer generates an invalid TZif file that omits leap second information for the range LO..B when LO falls between two leap seconds A and B. Instead, it generates a TZif version 4 file that represents the previously-missing information. The TZif reader now allows the leap second table to begin with a correction other than -1 or +1, and to contain adjacent transitions with equal corrections. This supports TZif version 4. The TZif reader now lets leap seconds occur less than 28 days apart. This supports possible future TZif extensions. Fix bug that caused 'localtime' etc. to crash when TZ was set to a all-year DST string like "EST5EDT4,0/0,J365/25" that does not conform to POSIX but does conform to Internet RFC 8536. Fix another bug that caused 'localtime' etc. to crash when TZ was set to a POSIX-conforming but unusual TZ string like "EST5EDT4,0/0,J365/0", where almost all the year is DST. Fix yet another bug that caused 'localtime' etc. to mishandle slim TZif files containing leap seconds after the last explicit transition in the table, or when handling far-future timestamps in slim TZif files lacking leap seconds. Fix localtime misbehavior involving positive leap seconds. This change affects only behavior for "right" system time, which contains leap seconds, and only if the UT offset is not a multiple of 60 seconds when a positive leap second occurs. (No such timezone exists in tzdb, luckily.) Without the fix, the timestamp was ambiguous during a positive leap second. With the fix, any seconds occurring after a positive leap second and within the same localtime minute are counted through 60, not through 59; their UT offset (tm_gmtoff) is the same as before. Here is how the fix affects timestamps in a timezone with UT offset +01:23:45 (5025 seconds) and with a positive leap second at 1972-06-30 23:59:60 UTC (78796800): time_t without the fix with the fix 78796800 1972-07-01 01:23:45 1972-07-01 01:23:45 (leap second) 78796801 1972-07-01 01:23:45 1972-07-01 01:23:46 ... 78796815 1972-07-01 01:23:59 1972-07-01 01:23:60 78796816 1972-07-01 01:24:00 1972-07-01 01:24:00 Fix an unlikely bug that caused 'localtime' etc. to misbehave if civil time changes a few seconds before time_t wraps around, when leap seconds are enabled. Fix bug in zic -r; in some cases, the dummy time type after the last time transition disagreed with the TZ string, contrary to Internet RFC 8563 section 3.3. Fix a bug with 'zic -r @X' when X is a negative leap second that has a nonnegative correction. Without the fix, the output file was truncated so that X appeared to be a positive leap second. Fix a similar, even-less-likely bug when truncating at a positive leap second that has a nonpositive correction. zic -r now reports an error if given rolling leap seconds, as this usage has never generally worked and is evidently unused. zic now generates a POSIX-conforming TZ string for TZif files where all-year DST is predicted for the indefinite future. For example, for all-year Eastern Daylight Time, zic now generates "XXX3EDT4,0/0,J365/23" where it previously generated "EST5EDT,0/0,J365/25" or "". (Thanks to Michael Deckers for noting the possibility of POSIX conformance.) zic.c no longer requires sys/wait.h (thanks to spazmodius for noting it wasn't needed). When reading slim TZif files, zdump no longer mishandles leap seconds on the rare platforms where time_t counts leap seconds, fixing a bug introduced in 2014g. zdump -v now outputs timestamps at boundaries of what localtime and gmtime can represent, instead of the less-useful timestamps one day after the minimum and one day before the maximum. (Thanks to Arthur David Olson for prototype code, and to Manuela Friedrich for debugging help.) zdump's -c and -t options are now consistently inclusive for the lower time bound and exclusive for the upper. Formerly they were inconsistent. (Confusion noted by Martin Burnicki.) Changes to build procedure You can now compile with -DHAVE_MALLOC_ERRNO=0 to port to non-POSIX hosts where malloc doesn't set errno. (Problem reported by Jan Engelhardt.) Changes to documentation tzfile.5 better matches a draft successor to RFC 8536 <https://datatracker.ietf.org/doc/draft-murchison-rfc8536bis/01/>. Here are links to the release files: https://www.iana.org/time-zones/repository/releases/tzcode2021b.tar.gz https://www.iana.org/time-zones/repository/releases/tzdata2021b.tar.gz https://www.iana.org/time-zones/repository/releases/tzdb-2021b.tar.lz The following convenience links are also available, although they may point to the previous release until the relevant caches are refreshed: https://www.iana.org/time-zones/repository/tzcode-latest.tar.gz https://www.iana.org/time-zones/repository/tzdata-latest.tar.gz https://www.iana.org/time-zones/repository/tzdb-latest.tar.lz Links are also available via plain HTTP, and via FTP from ftp://ftp.iana.org/tz/releases with the same basenames as above. Each release file has a GPG signature, which can be retrieved by appending ".asc" to the above URLs. Copies of these signatures are appended to this message. This release corresponds to commit 9ffa3f6e5019dfa7cfb5c0e4e8a84fa95adec704 dated 2021-09-24 16:23:00 -0700 and tagged '2021b' in the development GitHub repository at <https://github.com/eggert/tz>. Here are the SHA-512 checksums for the release files: 00fca7508cfbc42123065fe8087397c9dd2acbdda96f3bb0936187825348cf13538f1893f2d02bd8bfa3465427ca7a9a65451baffe39889bc58ba0a77a047806 tzcode2021b.tar.gz ca61d64af5ae791f337533c09d2b4f7caa645ecab7b9d13e9bcafc47c7c68535abe7c103c56bbd41d6bd913a8607f9c5187c8ce8a91b4891a750a643f89c8b51 tzdata2021b.tar.gz 326fb99666c8d5bb798a9c24d2869307620dce918d47fbedd7f765c91eb35ea44bf776f43cb00cde1944884150232ac6dcdc0194a0364e2d28f6470691cf9177 tzdb-2021b.tar.lz Here are the GPG digital signatures for the release files: -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmFOX/wACgkQ7ZfpDmKq fjRKwA//RVH1mmf13Uz99KBQZMc/meVaYT1YSpMqilocZo1w+i+Omai7Aw/r9u1e lnwLQukqjpCH4TJWdq8VuloL5ojN1ImoZuIRYECWRHOShxMaS9DLkPRr4qA9Fxic hladneiIglVrnzQbG4pH0Vnu9Qakb6I+1um8lCNiJHng84y5KAOIcZu1m9O+A1F1 bdik8Ddxc4qBluUvcq9n9aqWSgDBvIyCYik6bOo3lOd5zP1rcjSr8VJ+15cAkH4X hU/igj9qloyqAmoOyJOzIIwv63T3Xg63rH/V2hJWyux54ayP4Kt8nZqLYA9V8gFI V/HL5qNafSYEqguO2H3hTwURc3Utini8Oa2Ou89Ih0hkO+nySacc0ZnhaunmX7Ip D5Oj6A8kssG0Uj5fZqpqUp1FeRbziAinSdwTOpRxdkdeHI6tfS0XVnRvRiFATfTu oh9107e3okwKAb2UPJtr8Oev0uU8rz8+EorN9/PqJv0n2c3I69NUv6TudFVHM8uB lwG3hUNtWWYpK/rzwX8AQkwTrOHMN3VJ94T8xaTm13/jtk6R/+GgSjXKC2C9XZG6 5uvi6et06WnRVRO+V5TwnQdfY85pe5nqRDLeo0clxdkAvx6fslLpz9YNacLV/Gn8 0UIGt9CBKjE+PU1F5w+O/5btA/1aTojuSpKscdzgQIzXTfDlTZo= =+McC -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmFOX/0ACgkQ7ZfpDmKq fjRYmg/9H3rMpV7uQdd+G2K0wybdzTH6vJiNQClWE1+wqCPh/L3e8kCbPIjSo7MF SFV/Pu4EDb9kjeA2ruEMYlLnpg5nTP7dYfFRsRDcQJ5Yw70luNImm1ipUkKr9o5Q oQqYFKzxvB0G1rE+/gMaxmCHtGaJnv0DEChhmAS5U4j48z71Fn3+UJIU9XPEaODD U1Fw62xDsxIlFKjZ9UvilhlVRMnnP5nK9hjrsFKn7OGbxYvkdaRoK5f3M+G5nGXh L9nZcE0cd/7zhD3+wlttcH+xw3b+5P+7sxMhucoWQXEl3KyIklh97fi7jzHBHz+s DRYLZv/yPoEp94QyCfaYdvWL/i4OX4/9YnXK3ruXDcEV2y8Zl7Wc70Ihxk3I2XAb S4YeMcb30uls93QUdSmuhpEEUWrS5e45OnPy9RnT/VnpCalxsukudSNRzuvivKZn TsPpf90VUtI9ncLZ4l7OoNVXSj5pJ6DS+V1nCesEQyfyFnFvgK/rogCZ0yt+Cosp zaXwBtGyOWwWsGgXHGdJoiQqt/FF8o387EL95vpFr9BRSdSQoKd6K9RrRIH9fuy/ nnpaksD86fx+WbdLMtbHzsZgCqL1RTGO+kc35Qlr3vqH02UAZiwC9l3DHS9SA01c MGDy9zaiLsL/8/lUV3AP31dEP1+DY+BXvdFhIJkmIceBUf7zl0E= =PO3W -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmFOX/4ACgkQ7ZfpDmKq fjSaPg//ZlKREhlxjnstpEl6W3x4sStpUrF/Kebp62txYoCjbK22EDnw4BbE0wFh BcIBGbfxioC2+1gAjG57LK0RzTqFPPuDA69qYIZFk+xLrREISDqrGHViLGkFEgm5 jEDamuGW59UoBdnu4Klp1JAd7hvYQYEbbVaIVsrUlAL99OTyujeA6QoZdIjM43eh jx4g1P/XuHBqJEH7d9kOM5tBCRvgFhhcu/s4vOvrfFibRHRimYBuPlep5nJ88bb/ UyCQ1oYIQucWtl+DOszICl/GTmuM33FMTeAX6OrlGxwON6KPI2qNzAaQVpK1apB/ qF9dTnOVP8pygW6HkiFwNOKx4mplB2V8f1eqLT9mfdOQsEWPRuDyUvejBIr/Hmww jHF1w9TX8FxND2KQmcfZNTlKqYcw1O8Vz4m+0UnDzNuLiZAsnTBTrfnKMnVrTOFt 1K6KKK+v5y4WYu+pE36cIBM2YxITEpD+YrRr7G1ilzVgRH5FRGCJsxJu0O+BO35z rv9qVnJz0xISMJs+qSdJT8v4W4Uc6+crnHjAc7T7eAin3i3y/GY/MA44isCACmhx +Rq165laaHXnqTOgQfHhGjigJoH3JCnDYUwg6q+fMMBU2eALkOs+IbgdfVB3hoyo UOlYH/A25nuI0PrRgUKsN6N2lrfPjq3bM4twDw33BOyGJ/LN88w= =aNBd -----END PGP SIGNATURE----- PS. If your tzdata parser does not yet support negative DST offsets or times past 24:00, or if it insists on a 'pacificnew' file that is no longer present, this release's data entries can be turned into a rearguard-format tarball that should work even with these older parsers. This is intended to be a temporary transition aid for these parsers. To generate a rearguard-format tarball, obtain the full distribution as described above, and run the command 'make rearguard_tarballs' on a development host. Or you can run 'make rearguard.zi' to generate a single file that can be fed directly to a parser that works like 'zic'.

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Discussion on LWN on the equity controversy
by Sanjeev Gupta Oct. 1, 2021

Oct. 1, 2021

Folks, On Linux Weekly News (which actually is about more than Linux), there is a summary and discussion on the issues raised here. LWN has a very high signal/noise ratio, I find. I have been a paid subscriber for a couple of decades. Here is a link (LWN allows subscribers to generate a link to an article for viewing by non-subscribers, all content s free after a week): https://lwn.net/SubscriberLink/870478/9dcc3764b87edfaf/ Thanks, -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane

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