FW: Problem in DST fall back procedure
I'm forwarding this message from Avi Koski, who is not on the time zone mailing list. Those of you who are on the time zone mailing list should direct replies appropriately. AK: what's the exact geographic location of the place where things are wrong? --ado ________________________________ From: Koski Avi [mailto:Avi.Koski@comverse.com] Sent: Monday, November 13, 2006 10:46 AM To: tz@lecserver.nci.nih.gov Cc: Sagi Yoav Subject: Problem in DST fall back procedure Hi, We are using the files from: ftp://elsie.nci.nih.gov/pub/ There is a problem in the fall back procedure, which we encountered in all our tested platforms (Tru64 4.0D/4.0F, Linux AS3 Update 8, Solaris 9). We cahnged time to 01:55 , 4 Nov 2007. The time advances normally from 02:00hrs on and "does not fall back to 01:00hrs as desired". # date Sun Nov 4 02:01:23 EST 2007 # zdump -v US/Alaska | grep 2007 US/Alaska Sat Nov 3 23:05:42 2007 AKDT US/Alaska Sun Mar 11 10:59:59 2007 GMT = Sun Mar 11 01:59:59 2007 AKST isdst=0 gmtoff=-32400 US/Alaska Sun Mar 11 11:00:00 2007 GMT = Sun Mar 11 03:00:00 2007 AKDT isdst=1 gmtoff=-28800 US/Alaska Sun Nov 4 09:59:59 2007 GMT = Sun Nov 4 01:59:59 2007 AKDT isdst=1 gmtoff=-28800 US/Alaska Sun Nov 4 10:00:00 2007 GMT = Sun Nov 4 01:00:00 2007 AKST isdst=0 gmtoff=-32400 # zdump -v Canada/Yukon | grep 2007 Canada/Yukon Sat Nov 3 23:06:07 2007 YDT Canada/Yukon Sun Mar 11 10:59:59 2007 GMT = Sun Mar 11 01:59:59 2007 YST isdst=0 gmtoff=-32400 Canada/Yukon Sun Mar 11 11:00:00 2007 GMT = Sun Mar 11 03:00:00 2007 YDT isdst=1 gmtoff=-28800 Canada/Yukon Sun Nov 4 09:59:59 2007 GMT = Sun Nov 4 01:59:59 2007 YDT isdst=1 gmtoff=-28800 Canada/Yukon Sun Nov 4 10:00:00 2007 GMT = Sun Nov 4 01:00:00 2007 YST isdst=0 gmtoff=-32400 # Is there a patch to this problem? Please advise, Avi Koski - Comverse Ltd., Platform Linux Group Tel: +972-50-7348330
"Olson, Arthur David \(NIH/NCI\) [E]" <olsona@dc37a.nci.nih.gov> writes:
We cahnged time to 01:55 , 4 Nov 2007. The time advances normally from 02:00hrs on and "does not fall back to 01:00hrs as desired".
My guess is that you set the time to the _second_ 01:55 on that date. So the clock _should_ advance normally through 02:00. If you want to observe a jump, you have to set the time to the _first_ 01:55 on that date.
# date Sun Nov 4 02:01:23 EST 2007
So far so good; that's a valid time stamp.
# zdump -v US/Alaska | grep 2007 US/Alaska Sat Nov 3 23:05:42 2007 AKDT US/Alaska Sun Mar 11 10:59:59 2007 GMT = Sun Mar 11 01:59:59 2007 AKST isdst=0 gmtoff=-32400 US/Alaska Sun Mar 11 11:00:00 2007 GMT = Sun Mar 11 03:00:00 2007 AKDT isdst=1 gmtoff=-28800 US/Alaska Sun Nov 4 09:59:59 2007 GMT = Sun Nov 4 01:59:59 2007 AKDT isdst=1 gmtoff=-28800 US/Alaska Sun Nov 4 10:00:00 2007 GMT = Sun Nov 4 01:00:00 2007 AKST isdst=0 gmtoff=-32400
This is also valid behavior; the clock jumps backward just before 02:00 on 2007-11-04. Your example for Yukon was similar. So far, I don't see a bug.
Avi, Paul is correct. Try setting the time explicitly using UTC: "date -u 110409552007". As a side issue... I am puzzled as to the output from "zdump -v Canada/Yukon" you provided in your e-mail. It is reporting time zone abbreviations of YST and YDT and showing the same offsets as AKST and AKDT. Canada/Yukon is mapped to America/Whitehorse which has been using PST/PDT for many years. When I run "zdump -v Canada/Yukon | grep 2007" I get a very different output from you. This is what I get: Canada/Yukon Sun Mar 11 09:59:59 2007 UTC = Sun Mar 11 01:59:59 2007 PST isdst=0 Canada/Yukon Sun Mar 11 10:00:00 2007 UTC = Sun Mar 11 03:00:00 2007 PDT isdst=1 Canada/Yukon Sun Nov 4 08:59:59 2007 UTC = Sun Nov 4 01:59:59 2007 PDT isdst=1 Canada/Yukon Sun Nov 4 09:00:00 2007 UTC = Sun Nov 4 01:00:00 2007 PST isdst=0 This is what you reported: Canada/Yukon Sun Mar 11 10:59:59 2007 GMT = Sun Mar 11 01:59:59 2007 YST isdst=0 gmtoff=-32400 Canada/Yukon Sun Mar 11 11:00:00 2007 GMT = Sun Mar 11 03:00:00 2007 YDT isdst=1 gmtoff=-28800 Canada/Yukon Sun Nov 4 09:59:59 2007 GMT = Sun Nov 4 01:59:59 2007 YDT isdst=1 gmtoff=-28800 Canada/Yukon Sun Nov 4 10:00:00 2007 GMT = Sun Nov 4 01:00:00 2007 YST isdst=0 gmtoff=-32400 Did you make any changes to the source files before you compiled and installed? -chris -----Original Message----- From: Paul Eggert [mailto:eggert@CS.UCLA.EDU] Sent: November 13, 2006 2:00 PM To: avi.koski@comverse.com Cc: tz@lecserver.nci.nih.gov Subject: Re: FW: Problem in DST fall back procedure "Olson, Arthur David \(NIH/NCI\) [E]" <olsona@dc37a.nci.nih.gov> writes:
We cahnged time to 01:55 , 4 Nov 2007. The time advances normally from 02:00hrs on and "does not fall back to 01:00hrs as desired".
My guess is that you set the time to the _second_ 01:55 on that date. So the clock _should_ advance normally through 02:00. If you want to observe a jump, you have to set the time to the _first_ 01:55 on that date.
# date Sun Nov 4 02:01:23 EST 2007
So far so good; that's a valid time stamp.
# zdump -v US/Alaska | grep 2007 US/Alaska Sat Nov 3 23:05:42 2007 AKDT US/Alaska Sun Mar 11 10:59:59 2007 GMT = Sun Mar 11 01:59:59 2007 AKST isdst=0 gmtoff=-32400 US/Alaska Sun Mar 11 11:00:00 2007 GMT = Sun Mar 11 03:00:00 2007 AKDT isdst=1 gmtoff=-28800 US/Alaska Sun Nov 4 09:59:59 2007 GMT = Sun Nov 4 01:59:59 2007 AKDT isdst=1 gmtoff=-28800 US/Alaska Sun Nov 4 10:00:00 2007 GMT = Sun Nov 4 01:00:00 2007 AKST isdst=0 gmtoff=-32400
This is also valid behavior; the clock jumps backward just before 02:00 on 2007-11-04. Your example for Yukon was similar. So far, I don't see a bug.
Chris, The result I got refer to Tru64 4.0D (HP) machine. I just modified the source file "northamerica", before running zic. /Avi -----Original Message----- From: Chris Walton [mailto:Chris.Walton@telus.com] Sent: Monday, November 13, 2006 9:54 PM To: Koski Avi Cc: tz@elsie.nci.nih.gov Subject: RE: FW: Problem in DST fall back procedure Avi, Paul is correct. Try setting the time explicitly using UTC: "date -u 110409552007". As a side issue... I am puzzled as to the output from "zdump -v Canada/Yukon" you provided in your e-mail. It is reporting time zone abbreviations of YST and YDT and showing the same offsets as AKST and AKDT. Canada/Yukon is mapped to America/Whitehorse which has been using PST/PDT for many years. When I run "zdump -v Canada/Yukon | grep 2007" I get a very different output from you. This is what I get: Canada/Yukon Sun Mar 11 09:59:59 2007 UTC = Sun Mar 11 01:59:59 2007 PST isdst=0 Canada/Yukon Sun Mar 11 10:00:00 2007 UTC = Sun Mar 11 03:00:00 2007 PDT isdst=1 Canada/Yukon Sun Nov 4 08:59:59 2007 UTC = Sun Nov 4 01:59:59 2007 PDT isdst=1 Canada/Yukon Sun Nov 4 09:00:00 2007 UTC = Sun Nov 4 01:00:00 2007 PST isdst=0 This is what you reported: Canada/Yukon Sun Mar 11 10:59:59 2007 GMT = Sun Mar 11 01:59:59 2007 YST isdst=0 gmtoff=-32400 Canada/Yukon Sun Mar 11 11:00:00 2007 GMT = Sun Mar 11 03:00:00 2007 YDT isdst=1 gmtoff=-28800 Canada/Yukon Sun Nov 4 09:59:59 2007 GMT = Sun Nov 4 01:59:59 2007 YDT isdst=1 gmtoff=-28800 Canada/Yukon Sun Nov 4 10:00:00 2007 GMT = Sun Nov 4 01:00:00 2007 YST isdst=0 gmtoff=-32400 Did you make any changes to the source files before you compiled and installed? -chris -----Original Message----- From: Paul Eggert [mailto:eggert@CS.UCLA.EDU] Sent: November 13, 2006 2:00 PM To: avi.koski@comverse.com Cc: tz@lecserver.nci.nih.gov Subject: Re: FW: Problem in DST fall back procedure "Olson, Arthur David \(NIH/NCI\) [E]" <olsona@dc37a.nci.nih.gov> writes:
We cahnged time to 01:55 , 4 Nov 2007. The time advances normally from 02:00hrs on and "does not fall back to
01:00hrs as desired".
My guess is that you set the time to the _second_ 01:55 on that date. So the clock _should_ advance normally through 02:00. If you want to observe a jump, you have to set the time to the _first_ 01:55 on that date.
# date Sun Nov 4 02:01:23 EST 2007
So far so good; that's a valid time stamp.
# zdump -v US/Alaska | grep 2007 US/Alaska Sat Nov 3 23:05:42 2007 AKDT US/Alaska Sun Mar 11 10:59:59 2007 GMT = Sun Mar 11 01:59:59 2007 AKST isdst=0 gmtoff=-32400 US/Alaska Sun Mar 11 11:00:00 2007 GMT = Sun Mar 11 03:00:00 2007 AKDT isdst=1 gmtoff=-28800 US/Alaska Sun Nov 4 09:59:59 2007 GMT = Sun Nov 4 01:59:59 2007 AKDT isdst=1 gmtoff=-28800 US/Alaska Sun Nov 4 10:00:00 2007 GMT = Sun Nov 4 01:00:00 2007 AKST isdst=0 gmtoff=-32400
This is also valid behavior; the clock jumps backward just before 02:00 on 2007-11-04. Your example for Yukon was similar. So far, I don't see a bug.
participants (4)
-
Chris Walton -
Koski Avi -
Olson, Arthur David (NIH/NCI) [E] -
Paul Eggert