Updated Australian time zone names/strings

Paul Eggert eggert at twinsun.com
Sat Apr 7 06:38:21 UTC 2001

> From: Robert Elz <kre at munnari.OZ.AU>
> Date: Sat, 07 Apr 2001 14:07:13 +1000
> For simply specifying a time having them the same works much better,
> as you never get odd things like "Sat Apr  7 13:59:33 AEDT 2001"
> which would be a date/time/zone combination that simply doesn't
> exist.

Oddities are rarer, but they still occur at times.  For example,
"Sun Aug 27 02:30:00 2000 EST" is a time stamp that didn't exist in
Sydney, as the clock jumped from 01:59:59 to 03:00:00 that morning.

Also, using a different abbreviation disambiguates time stamps within
one hour of the fall-back transition.  For example, with the current
tz database and TZ='Australia/Sydney', the string "Sun Mar 25 02:30:00
2001 EST" is ambiguous, as it could mean either 2001-03-24 15:30:00
UTC or 2001-03-24 16:30:00 UTC.  This ambiguity would not exist if
Sydney used a different abbreviation for summer time.

A practical example of this can be found in the accident reports
published by the Australian Transport Safety Bureau.  My guess is that
the officials there dislike abbreviations ending in "DT" as the phrase
"Summer Time" is more common, and they don't feel the need for the
leading "A" as their reports are only about Australian accidents.
However, they do need an unambiguous abbreviation so that their
accident reports are precise.  So they use EST/ESuT.  See, for
example, <http://www.basi.gov.au/occurs/ob9800604.htm>; it talks about
a fatal crash of a flight with scheduled departure at 1500 ESuT and
scheduled arrival at 1830 EST.

> Its the convenience of the latter that makes me think that the choice of
> "Summer Time" to go with "Standard Time" was very deliberate, so the
> abbreviation would remain the same.

That's an interesting theory, but I think it more plausible that it
was simply an accident.  Other locales that use the phrase "Summer
Time" do not have this problem (e.g. GMT/BST, CET/CEST) because (for
historical reasons) they do not use the phrase "Standard Time".  As
far as I know, only Australia combines the American phrase "Standard
Time" with the the British phrase "Summer Time".  Perhaps this was
because Australia imported the idea of time zones from America (as
Britain wasn't wide enough to need them), while importing the
daylight-saving terminology from Britain (as Australia used wartime
daylight-saving before the United States did).

> You can no more force those people sending from one of the very few
> mailers that still has that broken behaviour to update their
> timezone names than you can get them to update their mailers.

That's quite true.

A similar problem occurs in New Zealand, but for a different reason.
There, people mistakenly sometimes set their computers' equivalent of
TZ to 12 hours behind UTC instead of 12 hours ahead of it, and then
move their clock ahead by 24 hours to work around some of the problems
with the incorrect offset.  Their email headers say -1200, though, and
this causes their mail to get mis-sorted.

I chalk up most of these problems to inadequate time zone software
more than to inadequate mail software.  For example, a few people are
still stuck with POSIX time zones and must set TZ='NZST-12...'.  It is
easy to go wrong and set TZ='NZST+12' instead.

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