On 2 April 2013 14:38, Russ Allbery <rra@stanford.edu> wrote:

That's actually one thing that the current abbreviations for Australia get
right; they could be usable for indicating a time zone instead of an
offset because they don't change with daylight saving time.

Yes, abbreviations that don't change with DST are nice... but only that. Such abbreviations such as ET and PT are used frequently within the United States in advertisements, newspapers, and general communication. The question of "What zone is meant by CT in this context?" is easily answered with America/Chicago.

In Australia, the question then becomes, e.g., "What zone is meant by CST in this context?" That question is not so easily answered, if it is answerable at all. The case could be made that the user should be more specific, but that defeats the purpose of using the abbreviations in the first place.

Arizona in the United States provides an interesting study. While some "laymen" might consider their constant offset to "switch" between the common notion of MT and PT, my (limited) experience with Arizona is that most businesses and news outlets explicitly use the three-letter abbreviation MST.

I don't think anyone's applying this argument to Australia (I'm certainly not), but if we did, then Qld should use (A)EST while NSW/ACT/Vic/Tas use (A)ET; NT should use (A)CST while SA uses (A)CT; WA could then simply use (A)WT. There are three issues with that:

Abbreviations must be at least three characters to be POSIX-compliant, so the A becomes necessary for consistency.
Using ACT to refer to Australian Central Time, which is not the time in the ACT (Australian Capital Territory), would be even more confusing than we have now.
Unlike the United States, DST is the exception in Australia, not the rule.

So it seems natural to instead emphasize the exception. Arizona does this by being explicit with the S in its abbreviation. Australia can do this by replacing the S with a D when appropriate. This allows the humans using the abbreviations to more easily use them for time conversion.

On 2 April 2013 14:25, John Hawkinson <jhawk@mit.edu> wrote:

Two simple cases:

(1) I look at the Date: header and I want to know, without thinking too
hard, where the originator is.

(2) I can't remember if we are in daylight time or standard time so
I type "date" and look at the abbreviation.

The current Australian abbrevs do a poor job of both of those cases.

I, too, like to be able to get a sense of what a timestamp means without having to first think about what month it is, what season that means it is "down under", which parts of which countries observe DST, and when those DST changes just to determine an offset. For programmatic purposes, this is something computers do wonderfully with the help of tz, but when I get an email on my phone, the last thing I want to do is find a terminal to figure out what "09:00 Sydney time" means for me.

On 2 April 2013 14:25, John Hawkinson <jhawk@mit.edu> wrote:

If they are worthless to software, let's
make them useful to humans, please.

This is by far the most compelling argument I've seen yet, not just because I happen to agree with it.

--
Tim Parenti