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From: steveg@hammer.UUCP (Steve Glaser)
Newsgroups: net.micro.mac
Subject: Re: Daylight Savings Time vs. Macintosh
Message-ID: <1254@hammer.UUCP>
Date: Mon, 13-May-85 14:08:15 EDT
Article-I.D.: hammer.1254
Posted: Mon May 13 14:08:15 1985
Date-Received: Wed, 15-May-85 00:20:23 EDT
References: <622@utcs.UUCP> <1484@amdahl.UUCP> <911@peora.UUCP>
Reply-To: steveg@hammer.UUCP (Steve Glaser)
Organization: Tektronix, Wilsonville OR
Lines: 37
Summary: 

In article <911@peora.UUCP> jer@peora.UUCP (J. Eric Roskos) writes:
>>  Don't limit your horizons.  When I step on a plane in N.Y. and get off
>>  at S.F., I want Mac to say, "Time to turn back the clock."  I'm sure
>>  there is some simple hardware solution. Now there is an interesting
>>  engineering question. :-)
>
>Since this has a :-), I can't tell if it is a joke, or a comment on the
>original suggestion.
>
>The original suggestion actually was very reasonable.  As the author
>mentioned, Unix* handles DST correctly.  Except for two years which had
>anomalies, the rules for when daylight savings time starts and stops are
>simple and well-defined.  The code in Unix which handles this is very
>short, and equivalent code could easily be included in the Mac's OS.
>
>*Unix is a trademark of AT&T.

You're forgetting one very important point.  The Mac was intended to be
an *international machine*.  While we US Chauvinists might like it, the
fact is that the algorithm used in the US is not used everywhere.
There are places that don't use DST at all and some that use it but
have different rules.

Unix also uses GMT internally.  On the Mac, this would require
additional space in the nvram for timezone data.  Also, you would get
to solve all the things that unix punted on (saudia arabia uses solar
time, there are places with timezones that are n.5 hours off GMT
[n=integer], the translation from "minutes off GMT with dstflag" to
timezone name is not 1 to 1 outside the US, etc.)

BTW, I think the :-) refered to having the Mac automagically know that
you were in S.F.  Why the Mac would "ask" you to reset the clock I
don't know since it now has enough data to do it for you, I don't know,
but...

	Steve Glaser
	tektronix!steveg