topic Re: DST 2007 fallback in Operating System - HP-UX

DST 2007 fallback

Abhijeet_3 — Tue, 02 Oct 2007 03:12:18 GMT

Hi ,

After successful fallover DST 2007 change on March 11, 2007. Now it is time for fallback on November 04.

Is any new special instructions,patch available for this fallback.

We have PHCO_36097 tztab patch present on our HP-UX 11i v1.

Thanks
Abhijeet

Re: DST 2007 fallback

melvyn burnard — Tue, 02 Oct 2007 03:30:20 GMT

Have you checked your tztab file to see what date it will change?
According to the origional patch it includes both the Spring and the Fall changes.
Also, PHCO_36097 has ben superseded by PHCO_37053, but you shouldn't need it unless you ar eon New Zealand time

Re: DST 2007 fallback

Steven E. Protter — Tue, 02 Oct 2007 03:49:41 GMT

Shalom,

You seem current on patching. If your government has not made any changes since you last patched, you should be fine.

SEP

Re: DST 2007 fallback

whiteknight — Tue, 02 Oct 2007 11:11:08 GMT

Abhijeet,

the latest patch is PHCO_37053 for New Zealand timezone

( SR:8606494752 CR:JAGag46685 )
Daylight Saving time NZDT for New Zealand time zone
NZDT-12NZDT ceases one hour earlier than expected.

HP DST info
http://h10072.www1.hp.com/dst/

WK

Re: DST 2007 fallback

A. Clay Stephenson — Tue, 02 Oct 2007 11:26:08 GMT

Rather than relying upon "it's probably ok" why not ask the box itself. The attached perl script will check for you. Because it uses the same underlying libc() functions that standard commands such as date use, if this script works then the standard commands and applications which use the same libc() functions will also work.

Use it like this:
dst.pl -n

to display the exact seconds before and after the next time transition for the current TZ setting.

Invoke as dst.pl -u for full usage.

Re: DST 2007 fallback

Geoff Wild — Tue, 02 Oct 2007 12:03:21 GMT

No - there was only 1 patch - and you have it.

The dst.pl script that Clay posted works great:

# dst.pl
Sun Mar 11 01:59:59 MST 2007 --> Sun Mar 11 03:00:00 MDT 2007
Sun Nov 04 01:59:59 MDT 2007 --> Sun Nov 04 01:00:00 MST 2007

Rgds...Geoff

Re: DST 2007 fallback

pnvs — Tue, 16 Oct 2007 10:40:23 GMT

Hi all,
I ran the above script in all our servers and got the below output.

Sun Mar 11 01:59:59 EST 2007 --> Sun Mar 11 03:00:00 EDT 2007
Sun Nov 04 01:59:59 EDT 2007 --> Sun Nov 04 01:00:00 EST 2007

Is it means no need to take any manual action for the DST happening on 4th november? all our servers located in USA & Canada.

Re: DST 2007 fallback

TwoProc — Tue, 16 Oct 2007 11:14:33 GMT

Nice script A. Clay. Thanks!

Re: DST 2007 fallback

JoAnn Nagel — Tue, 16 Oct 2007 16:20:10 GMT

I acturally changed our test server time to November 4, 2007 at 1:59:00 AM and watched for it to fall back. Unfortunately, it did not do as it should. I have patch PHCO_37053 on my 11.11 system. Has anyone else actually tested by changing the system date and seen it work?

Re: DST 2007 fallback

A. Clay Stephenson — Tue, 16 Oct 2007 16:59:30 GMT

>>> I acturally changed our test server time to November 4, 2007 at 1:59:00 AM and watched for it to fall back. Unfortunately, it did not do as it should. I have patch PHCO_37053 on my 11.11 system. Has anyone else actually tested by changing the system date and seen it work?

The problem with this approach is that you chose an ambiguous time. 4-Nov-2007 01:59:00 AM could be either Standard or Daylight Saving Time. Had you set the time to 00:59:00 then that would not have been an ambiguous time although you would have had to wait an hour. The problem with setting the system time ahead is that you also have to set the time back and that can cause all kinds of problems with timestamp sensitive data such as databases and makefiles. Use the Perl script, it is a much safer and completely reliable test as it doesn't actually change the system time, it jut sends the epoch seconds to the standard routines and displays the results.

Re: DST 2007 fallback

JoAnn Nagel — Wed, 17 Oct 2007 11:36:05 GMT

Yeah, after thinking about it, that does make sense. I ran the script and it came up with
Sun Nov 04 01:59:59 EDT 2007 --> Sun Nov 04 01:00:00 EST 2007
so I guess I have to trust it!
Thanks, Clay!