From: jcowan@reutershealth.com
Date: Fri May 07 2004 - 16:53:19 CDT
Philippe Verdy scripsit:
> I do agree. The fact that both "Europe/Istanbul" and "Asia/Istanbul"
> are referenced is probably not really political, but it reflects
> the fact that this city is on both continents, and that it's timezone
> covers more than just this city. Someone leaving on the Asian area near
> the city, but not in Istanbul must just wonder why its timezone is not
> defined in the "Asia" subcategory, and why he must select it in Europe
> (the reverse is possible).
Correct.
> So the database aliases one to the other. Aliases are used for timezones
> that are compeltely equivalent on the whole timeframe considered
> (apparently only starting in the early years of last century).
The cutoff date is 1970-01-01; if two timezones have been the same ever since
then, they are not separately encoded *unless* they are in separate national
jurisdictions (because after all it is the nation-state which sets up the
rules). This date is the Posix zero point.
> when in fact solar time was most frequently used (with lots of
> approximations) rather than official times.
Standard time dates to the 1890s in Europe and North America; basically, its
existence reflected the need for railroads to use a single time zone (or as few
as possible).
> What I don't know is if the Riyadh Solar Time is still in use today in
> Sauda Arabia (the Olson's database only contains rules for 1987-1989).
> in
I believe that it is not. The intention was to set sunset (the beginning of
the Islamic day) to 00:00 local time, but the difficulties in doing so
were simply too great.
> As well the "yearistype.sh" script is quite bogous if used to determine
> leap years (is it useful or correct for US election years?).
It is (the U.S. elects presidents in years that are divisible by 4
and greater than 1787, when the present constitution came into effect).
No actual time zone depends on whether the year is a presidential election
year, though the idea was proposed at one time.
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