Subject: Re: Updated Australian time zone names/strings

From: David Madeo <[email-masked]>
Date: Fri, 06 Apr 2001 00:20:42 -0400

<Caution: cross posted to both ietf-calendar and tz mailgroups.    Please
reply carefully>

Since I'm a lurker on both the tz and ietf lists, occasionally I see that
it's appropriate to mix the audiences.  This thread from the tz list is
whether the tz maintainers should be trying to uniquify the timezone
abbreviations such as "EST" which can mean several different timezones
around the world, depending on whether you ask an Australian or an American.

Greg Black wrote:

> Paul Eggert wrote:
>
> | * How important are unique time zone abbreviations?
> |
> |   Here I tend to agree with the point (most recently made by Chris
> |   Newman) that unique abbreviations should not be essential for proper
> |   operation of software.
>
> I think this flies in the face of common sense and the old
> principle about being flexible in handling input while trying to
> make output as good as possible.

I'd certainly prefer unique and unambiguous abbreviations (AEST) as well as
unique names "Australia/Sydney" based on the Continent/Largest City.
Anytime we can reduce confusion and make something easier for people *and*
computers to understand, we should.

> || The final decision is Arthur David Olson's, since he's maintaining
> | the database.  My own mild preference for now (given what's been said
> | so far) would be to leave it alone.
>
> I know the decision is in Arthur David Olson's hands, but I
> would imagine that he will be responsive to the wishes of the
> affected parties.  I'm keen to see more input into this.

The tz database is the closest thing to a "standard" timezone listing.  As
such, there's a lot of benefit if it does the "right" thing.   I've cc'd the
ietf list since they are effectively "users" of this sort of data and might
have some input.

dmadeo

---

From: "rchapma6 ford.com" <[email-masked]>
Date: Fri, 6 Apr 2001 04:54:20 -0400

Your cross posting caution was noted
I similarly lurk on the ietf list and occasionally sally forth to pass
comment.

The issue of the ambiguity of abbreviations like "EST" might best be solved
by prefixing the three initials with the ISO Country Code see
http://itl5.itlnet.com/isocodes.htm for examples. So the Australian EST
would be AUEST and the US EST would be USEST. 

There may be another advantage to do with Daylight Savings/Summer Time.
These (I believe) are determined at national or regional level so those
countries who do observe Daylight Savings/Summer Time would have two entries
per time zone. 

for example:-
USEST  UTC -5:00
USEDT  UTC -4:00

Add to this the entry and exit criteria for Daylight Savings/Summer Time
(and I hope I get this correct!)

USEST  UTC -5:00 Last Sunday in September 
USEDT  UTC -4:00 Last Sunday in March
GBGMT  UTC  0:00 Last Sunday in October
GBBST  UTC +1:00 4th Sunday in March??

or the explicit dates if there is no sensible way of determining when the
clocks change!

For countries like Japan where they do not observe Daylight Savings the
entry would look like

JPxxx  UTC +8:00 

The absence of date showing non-observation

Hope that helps a bit

Roger Chapman
Specilaist, Collaborative Applications
Ford Systems Integration Center
Information Technology and eBusiness
Ford Motor Company

-----Original Message-----
From: David Madeo [mailto:[email-masked]]
Sent: 06 April 2001 05:21
To: Greg Black
Cc: Paul Eggert; [email-masked]; [email-masked]
Subject: Re: Updated Australian time zone names/strings

dmadeo