[tz] timezone DB distribution

Juergen Naeckel naeckel at adobe.com
Mon Aug 17 21:07:34 UTC 2020

Hi again,
I tried to use the data provided in the timezone files.  I ran some consistency checks.  I think I found some inconsistencies.
Zone America/Barbados – has rule BARB, but none of the BARB rules is currently valid.
Zone America/Costa_Rica – has rule CR, but none of the CR rules is currently valid.Zone America/El_Salvador – has rule BARB, but none of the rules is currently valid
Zone America/Guatemala – has rule Salv, but none of the rules is currently valid
Zone America/Tegucigalpa – has rule Hond, but none of the rules is currently valid

The zone Africa/Johannesburg uses an undefined rule SA
The zone Africa/El_Aaiun uses an undefined rule Morocco
The zone Africa/Casablanca uses an undefined rule Morocco
The zone Indian/Mauritius uses an undefined rule +04/+05
The zone Pacific/Tongatapu uses an undefined rule Tonga
The zone Pacific/Rarotonga uses an undefined rule Cook
The zone Australia/Brisbane uses an undefined rule AQ
The zone Australia/Perth uses an undefined rule AW
The zone Australia/Darwin uses an undefined rule Aus
The zone America/Montevideo uses an undefined rule Uruguay
The zone America/Guayaquil uses an undefined rule Ecuador
The zone America/Cuiaba uses an undefined rule Brazil
The zone America/Campo_Grande uses an undefined rule Brazil
The zone America/Sao_Paulo uses an undefined rule Brazil
The zone America/Argentina/Tucuman uses an undefined rule Arg
The zone America/Argentina/Cordoba uses an undefined rule Arg
The zone America/Argentina/Buenos_Aires uses an undefined rule Arg

I spot checked several of those – and there is no more daylight saving for those regions.  Thus, the zone definition should contain a dash.

I noticed some more inconsistencies specific to the “asia” file.  The data separator is flexible.  Everywhere, the tab is used as a separator.  Here, the tab and the space are used interchangeably.  Also in all the other files, the “Zone” is followed by a space and then the name.  In this asia file, I noticed frequent use of tabs in between.  Do you use space and tab alike?
[cid:image001.png at 01D674B8.E58BB0B0]

Thank you,

From: Juergen Naeckel
Sent: Monday, August 17, 2020 3:02 PM
To: tz at iana.org
Subject: timezone DB distribution

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 at 01D674B5.472618F0]
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 at 01D674B5.472618F0]

Can you shed some light on this?

Thank you!  Not only for an answer but also for researching and compiling this list.

Juergen Naeckel
T 617 766 2381 |  C 617 775 3874
naeckel at adobe.com<mailto:naeckel at adobe.com>
[cid:image004.png at 01D674B5.472618F0]

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