[tz] Europe/Amsterdam

[Brian Inglis]

On 2023-10-17 05:08, Leo Bekhuis via tz wrote:
> We have some kind of a short discussion on a timezone.
> We are looking for the correct answer.
> *Is Europe/Amsterdam currently an IANA compliant timezone?*

The IANA RFC specifies only management, maintenance, and release procedures for 
tzdb data, so as a whole it is compliant to that RFC.

Individual zone data are discussed on the list, and decisions and changes are 
summarized in the comments for each zone and rule in each data file, and on the 
mailing list at (sometimes much) greater length.

> We see in the most recent version it is linked backwards to Europe/Brussels

With some builds, intended to reduce the distributed size, all zones with the 
same time history agreeing since 1970, may be consolidated by ignoring history 
before 1970, and linking to a zone with a larger population centre and the same 
history.*

> But does that means that Europe/Amsterdam is no longer compliant.

Compliant to what decree, law, regulation, or standard?

> Is zone.tab an actual representation of all current iana compliant timezones?

That file or its consolidated alternative zone1970.tab may be used in a build to 
control the zones built.*

> We read a first comment line "tzdb timezone descriptions (deprecated version)"

That is the current maintainer's view of the use of that file and related history.

The development repository can provide the detailed history of each data file, 
zone, and rule since project inception in SCCS in 1986:

	https://github.com/eggert/tz

although consolidation may have made it harder to find historical details.

*It is up to each distro, packager, org, or developer, how they decide to tailor 
the features and size of the build of the utilities and data files they use: 
whether to include backward compatibility zones and links; and whether zones and 
rules use and generate values which are mainstream "standard" main, backwards 
compatible "rearguard", or require leading edge utilities and libraries to 
handle "vanguard"; whether they include POSIXRULES, leap seconds and TAI offset 
"right" data files, various time_t types, etc.

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer     but when there is no more to cut
                                 -- Antoine de Saint-Exupéry