Timezone translations

Peter Ilieve peter at aldie.co.uk
Sun Jun 5 11:21:40 UTC 2005

On 5 Jun 2005, at 00:04, Mark Davis wrote:

> In this particular case, however, it is unclear what we should do;  
> that's
> why I tried to spell out the issues. It would be very easy for us  
> to change
> the summer time to British Summer Time, but for the winter time  
> there is a
> problem, because of the ambiguity of the use of the term "GMT".

But lots of the abbreviations are ambiguous. When I first got involved
with this sort of stuff, back in the days of 4.1c bsd or so, I remember
the surprise of discovering Bering Straits Time for example. It's hard
to avoid this ambiguity when you've only got three letters, and one
of them is almost bound to be T.

It's the concept of "can't use the long name Greenwich Mean Time or the
abbreviation GMT" (from your previous mail) that I'm struggling to
understand. I've been on the timezone mailing list for a long time,
and I like to think I've contributed something towards documenting the
convoluted history of UK summer time changes. During that time I've seen
Arthur Olson and Paul Eggert work to try to make sense of the chaotic
human messiness of timezone naming, and try and catch up with the
capricious changes that politicians make to the clocks. There's
no notion of "can't" in this. If someone pops up and produces credible
evidence that some group of people call their timzeone XYZ, then XYZ
goes in the database. It reflects what people use in their everyday

The CLDR doesn't seem to be like that. Your talk of roundtripping,
parsing and so on implies some higher purpose. I wrote higher as
the result is that I "can't" call my local winter time by the only
name by which I have known it ever since I can remember.

Take the famous man on the Clapham omnibus, now armed with a laptop
and cadging Internet access from a nearby insecure WiFi access point
while his bus is stuck in the traffic. He wants the dates in his emails
to look right, and that means having GMT in the winter. If you tell
him that he can't have that because some bunch of programmers who he's
never heard of say it will upset the internal workings of some software
he's never heard of either he is unlikely to be impressed. If you ask
him if he would mind having "GMT (UK)" instead to fix this he is likely
to give a dusty answer.

> Here is the problem. [calendar scheduling details snipped]

That is indeed a problem. I don't have an answer to it. I suspect the
answer will involve using UTC times and a timezone name like Europe/ 
with the Europe/London taken from the preferences set for the particular
application or from the user's default settings.

Going back to your suggestion that I file a bug report, I visited that
URL and it reminded me why I didn't try and file a bug before. It
has a warning that I must read the Data Formats and Filing Bug Reports
before submitting. OK, I thought, maybe I can skip the data formats
one and just read the one about filing, but no, that page not only
repeats the instruction to read the data formats page but adds more
instructions to consult the comparison and by-type charts.

I'm sorry, but I'm not going to do all that, especially when you've
told me in advance that the only terms I would use for UK non-summer
time will be rejected. What's the point?

Finally, I'll repeat the question from my first mail about this, which
I forgot to add to my last mail: where did the current data for
Europe/London in the en_timezones.html come from?

         Peter Ilieve        peter at aldie.co.uk

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