My confusion with Asia/Aqtau
chucks at lmi.net
Mon Jul 21 18:38:44 UTC 2003
I'm using Darwin (Mac OS X 10.2.6) and I'm getting different output
than you for "zdump -v Asia/Aqtau | grep 1995". Here is the output
that I'm getting:
Asia/Aqtau Sat Mar 25 18:59:59 1995 GMT = Sat Mar 25 23:59:59 1995
Asia/Aqtau Sat Mar 25 19:00:00 1995 GMT = Sun Mar 26 01:00:00 1995
Asia/Aqtau Sat Sep 23 17:59:59 1995 GMT = Sat Sep 23 23:59:59 1995
Asia/Aqtau Sat Sep 23 18:00:00 1995 GMT = Sat Sep 23 22:00:00 1995
Does this indicate that I'm using a different version of the timezone package?
How can I determine what version of the timezone package is installed
on my system? I hope that I'm using version 2003a.
At 8:18 AM -0400 7/18/03, Olson, Arthur David (NIH/NCI) wrote:
>Dave Rolsky's interpretation of what the "asia" file *says* is happening
>is correct, as witness output from "zdump -v Asia/Aqtau | grep 1995":
> Asia/Aqtau Sat Mar 25 20:59:59 1995 UTC = Sun Mar 26 01:59:59 1995
> Asia/Aqtau Sat Mar 25 21:00:00 1995 UTC = Sun Mar 26 03:00:00 1995
> Asia/Aqtau Sat Sep 23 17:59:59 1995 UTC = Sat Sep 23 23:59:59 1995
> Asia/Aqtau Sat Sep 23 18:00:00 1995 UTC = Sat Sep 23 23:00:00 1995
> Asia/Aqtau Sat Sep 23 21:59:59 1995 UTC = Sun Sep 24 02:59:59 1995
> Asia/Aqtau Sat Sep 23 22:00:00 1995 UTC = Sun Sep 24 02:00:00 1995
>(Recall that for each time change zic produces a "before" and "after" line;
>six lines above means there were three changes in 1995).
>I don't know *really* happened in Asia/Aqtau in 1995;
>if there was indeed just one change to clocks, the "1995 Sep lastSun" line
>From: Dave Rolsky [mailto:autarch at urth.org]
>Sent: Friday, July 18, 2003 1:34 AM
>To: tz at lecserver.nci.nih.gov
>Subject: My confusion with Asia/Aqtau
>I'm trying to implement a parse/code generator based on the Olson DB
>_text_ files (not binary).
>I think I've got it mostly working, but there's some strange edge cases.
>One of them involves Asia/Aqtau, and I'm trying to figure out if I'm
>_really_ understanding what the file indicates.
>The observances for this zone include the following:
> 5:00 RussiaAsia AQT%sT 1995 Sep lastSun # Aqtau
> 4:00 RussiaAsia AQT%sT
>The RussiaAsia rules include the following rules which apply to those
> Rule RussiaAsia 1993 max - Mar lastSun 2:00s 1:00
> Rule RussiaAsia 1993 1995 - Sep lastSun 2:00s 0
> Rule RussiaAsia 1996 max - Oct lastSun 2:00s 0
>By my reading, this indicates the following transitions:
>* On Sep 24, 1995 at 00:00:00 _local_ time, the offset from UTC changes
>from 05:00 to 04:00. However, the DST rule is still in effect, so the
>total offset goes from 06:00 to 05:00.
>* On Sep 24, 1995 at 01:00:00 local time (2:00s == 1:00 wall when DST is
>in effect), the rule changes so that DST is no longer in effect, and the
>cumulative offset goes from 05:00 to 04:00.
>Is this _really_ correct? It seems awfully strange to have an observance
>change so close to a DST change. And if cases like these are possible,
>it's really going to complicate my code. But if it is correct, I do want
>to get it right in my code.
>OTOH, if it's wrong, and such things don't happen, I'd be just as happy to
>leave me code as is ;)
>House Absolute Consulting
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