[tz] timezone DB distribution

Brian Inglis Brian.Inglis at SystematicSw.ab.ca
Wed Aug 19 18:50:00 UTC 2020

On 2020-08-18 22:02, Guy Harris wrote:
> On Aug 18, 2020, at 8:43 PM, Tom Lane wrote:
>> While there's nothing particularly wrong with providing a zip-format
>> archive if Paul and Tim feel like doing so, I find myself skeptical that
>> there's actually a need for that.  The primary tzdata distribution is
>> *not* oriented towards the sort of end user who might find the lack
>> of a zipball to be an impediment.  Rather, that dataset is meant to
>> be consumed by OS-level packagers who will then push it out in
>> system updates for their respective platforms.  (Hello, Microsoft?)
> Unfortunately, Juergen may be working on the platform developed by the company you're addressing in that comment.
> I also infer from "I have to implement something in JavaScript that uses timezones.", in his original message, that he's not an "end user" in the sense of somebody just wanting to update their system's time zone files (which, as per the way you addressed the developer of the system, don't exist anyway :-)).
> However, what he said later was
>> 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.
> If he's providing software to a customer base, he might want to consider bundling the tzdb with the JavaScript software; even if the customer has a zipball, it'd be a pain for them to download and install.

J DOT N AT Adobe.com - possibly Javascript embedded in a [PDF] file - maybe form

Even xz compressed tzdb binaries occupy over 200KB - compressed sources 230KB+
(320+KB for zip) - sources nearly 1MB.

Javascript implementations should use system timezones and locales, to avoid
burdening the user with updates, as well as adapting to the user's preferences -
this one should do the same.

There are probably libraries with permissive BSD/MIT licences to access Windows
tz info and others to access tzdb that the OP could port or adapt.
Windows tz info won't help you much with history the last time I looked, and
tzdb is most accurate after 1970.

Windows time zone and "dynamic" (dated) zone info is well documented on the MS
site and you can display it using the Windows command:
$ reg query "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows
NT\CurrentVersion\Time Zones" /s /z

Systems I have admin control over show dates as e.g. 2020 Aug 19 Wed
12:23:19+0600 (except Windows won't include the time zone offset as it has no
user specifiable controls for that) - this one should do the same.

On 2020-08-18 22:13, Paul Eggert wrote:
> On 8/17/20 12:01 PM, Juergen Naeckel via tz wrote:>> First of all, a tar.gz is Linux specific.> Not really; the format is natively
supported by lots of operating systems,
> including macOS and Microsoft Windows 10.
Windows supports [BSD]tar on the command line: it was (relatively) unannounced
and unknown to me (and probably many others) until this; from its date, it may
have been added in the 2019-04 update!
Windows also supports zip in Explorer or newer Powershell, and cab with

On 2020-08-19 11:44, Guy Harris wrote:
> On Aug 19, 2020, at 8:41 AM, Paul Gilmartin wrote:>> And Single UNIX much prefers "pax" over "tar" nowadays.> "prefers" in what
sense?  And, in practice, how many pax archives using its
> extensions to ustar format are out there?
As for pax - I have heard of of it but have never come across anyone else who
even mentioned it or used it (except in man pages) and I don't remember noticing
if any distro installed it by default. POSIX invented something that wasn't as
good or useful as what was already available by the time it was implemented.

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

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