[tz] Pre-1970 data

Stephen Colebourne scolebourne at joda.org
Tue Nov 9 00:59:24 UTC 2021


On Mon, 8 Nov 2021 at 23:05, Paul Eggert via tz <tz at iana.org> wrote:
> On 11/8/21 13:30, Tony Finch via tz wrote:
> > The tz maintenance rules as written clearly said that each country should
> > have at least one zone until 2019. That rule started being broken in 2013
>
> If I'm reading the tzdb history correctly, from 2013–2019 the guidelines
> said only that there should typically be at least one name (not Zone)
> for each inhabited ISO country or territory. From 1997–2013 the
> guidelines also talked about names, not Zones. (There were no guidelines
> in this area before 1997.)
>
> So it appears that there has never been a guideline saying that each
> country should have at least one zone, and this means no such rule was
> ever broken.

Here is what it said in 2012:

"Include at least one location per time zone rule set per country.
One such location is enough.  Use ISO 3166 (see the file
iso3166.tab) to help decide whether something is a country.
However, uninhabited ISO 3166 regions like Bouvet Island
do not need locations, since local time is not defined there."

It was remove by this commit in 2013:
https://github.com/eggert/tz/commit/d3b025adb25554ee10b986850371e573df92733e

and re-added in the weaker form of "name" after I objected:
https://github.com/eggert/tz/commit/3d046bc0e4351c658d333d1dcc9c69ab15dfb743

IMO the original definition referred to Zone and not just name. That
is no surprise, because it is a very rational way to model timezones.

Stephen



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