My confusion with Asia/Aqtau

[Chuck Soper]

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 
AQTT isdst=0
Asia/Aqtau  Sat Mar 25 19:00:00 1995 GMT = Sun Mar 26 01:00:00 1995 
AQTST isdst=1
Asia/Aqtau  Sat Sep 23 17:59:59 1995 GMT = Sat Sep 23 23:59:59 1995 
AQTST isdst=1
Asia/Aqtau  Sat Sep 23 18:00:00 1995 GMT = Sat Sep 23 22:00:00 1995 
AQTT isdst=0

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.
Chuck


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
>AQTT isdst=0
>	Asia/Aqtau  Sat Mar 25 21:00:00 1995 UTC = Sun Mar 26 03:00:00 1995
>AQTST isdst=1
>	Asia/Aqtau  Sat Sep 23 17:59:59 1995 UTC = Sat Sep 23 23:59:59 1995
>AQTST isdst=1
>	Asia/Aqtau  Sat Sep 23 18:00:00 1995 UTC = Sat Sep 23 23:00:00 1995
>AQTST isdst=1
>	Asia/Aqtau  Sat Sep 23 21:59:59 1995 UTC = Sun Sep 24 02:59:59 1995
>AQTST isdst=1
>	Asia/Aqtau  Sat Sep 23 22:00:00 1995 UTC = Sun Sep 24 02:00:00 1995
>AQTT isdst=0
>
>(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
>needs tweaking.
>
>				--ado
>
>-----Original Message-----
>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
>Time
>  			4:00 RussiaAsia	AQT%sT
>
>The RussiaAsia rules include the following rules which apply to those
>observances:
>
>  Rule RussiaAsia	1993	max	-	Mar	lastSun	 2:00s	1:00
>S
>  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 ;)
>
>
>-dave
>
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