[tz] Why did you rename Russian zone name abbreviations
eggert at cs.ucla.edu
Thu Nov 3 15:12:57 UTC 2016
On 11/02/2016 01:58 PM, Alexander Belopolsky wrote:
> There may be exceptions historically, but as a rule Russian timezones
> are defined as fixed offsets from Moscow, so when Moscow Time changes,
> so do all the timezones.
This depends on what one means by "historical". Of course if one goes
back before 1930 things get weird by modern standards. However, even
recently, Vladivostok time has not been at a fixed offset from Moscow
time. For example, in 2014 (the last time Russian clocks changed in a
big way) Vladivostok changed seven hours earlier than Moscow did. Given
this typical practice, we cannot simply use "MSK+07" as the abbreviation
for Vladivostok time, as this abbreviation would be incorrect for
several hours whenever Russians change their clocks. Another practical
objection to "MSK+07" is that it would likely confuse users into setting
the POSIX TZ environment variable to "MSK+07", which would not work as
desired as it would use US Mountain Standard Time and call it "MSK".
Although abbreviations like "VLAT" avoid these problems, they run into
other issues. Because "VLAT" is not a fixed offset from UTC it departs
from the usual English-language semantics for time zone abbreviations,
misleading English-language readers. Also, what do we do with locations
like Europe/Barnaul, which switched from +06 to +07 in March of this
year? Should Barnaul use the abbreviation "OMST" (Omsk time) before
March, and "NOVT" (Novosibirsk time) after? Or should it now use "BART"
for all dates? Neither alternative is satisfactory and neither reflects
common practice in English. In contrast, using numeric abbreviations is
simple and requires no arbitrary inventions on our part.
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