Hi, this is just historical curiosity. I notice that "Rule CA" is applied to Zone America/Los_Angeles (and therefore US/Pacific and US/Pacific-New). But Zone PST8PDT does not have these same (California?) rules. Is there a political precedence for this? I see the bulk of the differences are the period from 1948 until the Uniform Time Act. But it's also curious that America/Los_Angeles references the US rule that defines PST from 1983 to 1918; whereas PST8PDT does not. Why this discrepancy between PST8PDT and the equivalent geographically named zones that use PST? If there is an online explanation for this kind of thing, I'd happily go RTFW. ../C
Curtis Doty <Curtis@GreenKey.net> writes:
Why this discrepancy between PST8PDT and the equivalent geographically named zones that use PST?
They're not geographically equivalent, since, for example, Seattle and Los Angeles used different rules before 1970. The PST8PDT rule is just a historical revenant, dating back to when the tz database was done a different way. It's not worth worrying much about. As a practical matter, we don't want it to be a link to Los Angeles because, as the northamerica file says, # We do these as separate Zones rather than as Links to avoid problems if # a particular place changes whether it observes DST.
I guess you are referring to this: # From Arthur David Olson, 2005-12-19 # We generate the files specified below to guard against old files with # obsolete information being left in the time zone binary directory. # We limit the list to names that have appeared in previous versions of # this time zone package. ... # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone EST -5:00 - EST Zone MST -7:00 - MST Zone HST -10:00 - HST Zone EST5EDT -5:00 US E%sT Zone CST6CDT -6:00 US C%sT Zone MST7MDT -7:00 US M%sT Zone PST8PDT -8:00 US P%sT I think that "obsolete information" is the keyword here. These timezones are obsolete but could be used by inexperienced users and therefore they are overwritten by new versions that will presumably be less incorrect. Why "CST" is not defined above when CST6CDT *is* is beyond me, by the way - compare to EST and EST5EDT. Regards, - Jesper Nørgaard Welen -----Original Message----- From: Curtis Doty [mailto:Curtis@GreenKey.net] Sent: Jueves, 18 de Enero de 2007 16:19 To: TZ Subject: variations on GMT-8:00 Hi, this is just historical curiosity. I notice that "Rule CA" is applied to Zone America/Los_Angeles (and therefore US/Pacific and US/Pacific-New). But Zone PST8PDT does not have these same (California?) rules. Is there a political precedence for this? ...
Date: Thu, 18 Jan 2007 22:48:04 -0600 From: Jesper Norgaard Welen <jnorgard@prodigy.net.mx> Message-ID: <!~!UENERkVCMDkAAQACAAAAAAAAAAAAAAAAABgAAAAAAAAADuUZBf7Jo0OrktsA6harmMKAAAAQAAAAUd9MbYQzk02NDykxxjciMwEAAAAA@prodigy.net.mx> | Why "CST" is not defined above | when CST6CDT *is* is beyond me, by the way - compare to EST and EST5EDT. Notice... | # We limit the list to names that have appeared in previous versions of | # this time zone package. which explains that. Why CST never existed as a separate zone in the past when the others did is a different question, which now is really no longer important - it is just a fact with which we need to deal. kre
" | # We limit the list to names that have appeared in previous versions of | # this time zone package. which explains that. Why CST never existed as a separate zone in the past when the others did is a different question, which now is really no longer important - it is just a fact with which we need to deal. Kre" Most likely because, unlike Eastern, Mountain, and Hawaiian, Central never had a location in the USA that actually used it while rejecting DST. (The needs of users in Saskatchewan were apparently not considered.) J Andrew Lipscomb, CPA*ABV, ASA Decosimo Corporate Finance 900 Tallan Building 2 Union Square Chattanooga, TN 37402 423.756.7100 Fax 423.266.6671 www.dcf.decosimo.com
participants (5)
-
Andy Lipscomb -
Curtis Doty -
Jesper Norgaard Welen -
Paul Eggert -
Robert Elz