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PPE timezone & ZMAIL

I just noticed some mail I had included a time zone of PPE which ZMAIL
didn't understand.  To fix it, use

	(time:assign-zone "PPE" 7)

From: RISKS Forum <risks@csl.sri.com>
Sender: RISKS Forum <risks@csl.sri.com>
Date: Mon, 26 Oct 92 19:20:50 PST
Subject: RISKS DIGEST 13.87

RISKS-LIST: RISKS-FORUM Digest  Monday 26 October 1992  Volume 13 : Issue 87

   ACM Committee on Computers and Public Policy, Peter G. Neumann, moderator

US presidential election year politics help cause time zone bugs (Paul Eggert)


Date: Mon, 26 Oct 92 14:47:57 PST
From: eggert@twinsun.com (Paul Eggert)
Subject: US presidential election year politics help cause time zone bugs

Several people on the west coast of the US reported that their Unix
systems failed to switch from daylight savings time to standard time
yesterday, 26 October 1992.  The reason?  When they originally
configured their systems, they were asked to choose one of the
following time zone rules:

	US/Alaska	US/Central	US/Hawaii	US/Pacific
	US/Aleutian	US/East-Indiana	US/Michigan	US/Pacific-New
	US/Arizona	US/Eastern	US/Mountain	US/Samoa

Some people chose `US/Pacific-New' instead of `US/Pacific'.
After all, who wants the old version when you can have the new version?

Unfortunately, `US/Pacific-New' stands for ``Pacific Presidential Election
Time'', which was passed by the House in April 1989 but never signed into law.
In presidential election years, this rule would have delayed the PDT-to-PST
switchover until after the election, to lessen the effect of broadcast news
election projections on last-minute west-coast voters.  Thus, US/Pacific-New
and US/Pacific have always been identical -- until yesterday.

This problem comes from combining Arthur David Olson's deservedly popular time
zone software (which you can FTP from elsie.nci.nih.gov in pub/tz92b.tar.Z)
with some overly terse vendor-supplied installation procedures.  No doubt Olson
did not use a more informative name like `US/Pacific-Presidential-Election'
because of the 14-character file name length limit in many Unix file systems.
In view of yesterday's experience, though, it seems unwise to make the
hypothetical choice available under any name, since it gives free rein to
Murphy's Law.