UTC vs GMT
eggert at twinsun.com
Thu Oct 3 23:20:21 UTC 1996
Date: Wed, 02 Oct 1996 15:06:06 -0500
From: kuhn at cs.purdue.edu ("Markus G. Kuhn")
Actually, I *do* suggest to change all occurances of the string GMT in
tzdata to UTC, the correct modern term.
That's a good suggestion for Etc/UTC and Etc/Universal, since anybody
who chooses those zones probably wants `UTC'. (Also, Etc/UCT should
probably generate `UCT' instead of the current `GMT'.) I'll draft a
patch along those lines.
However, I'm not sure it's a good idea for entries like Europe/London.
English speakers most commonly use `GMT' to describe the standard time
in Britain. The tz database tries to use an abbreviation for the
English phrase that's most commonly used for the time in a location.
Reasonable exceptions are only comment text references to historic
time zones before 1972 (when UTC replaced GMT as the reference time
As far as I know, GMT hasn't been an official reference time since the 1920s.
Even though the reference standard has changed a few times since then,
the public continues to call it `GMT'. This is understandable, since
the changes to the standard don't matter to most people.
I also used to believe that UTC was established in 1972, but I've been
corrected. UTC was introduced in 1961. It was originally kept close
to UT1 by periodically adding or subtracting steps of a fraction of a
second. 1972 is when the current leap-second regime was instituted.
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