topic Re: Daylight saving in Operating System - HP-UX

Daylight saving

Ravinder Singh Gill — Fri, 21 Oct 2005 04:43:24 GMT

Hi guys,

I need to know how the time on our HP servers will adjust to match the correct time after the change this weekend. I believe the time on the server will slow down for i.e. 2 hours at the end of which it will be the correct time, but what I need to know is what time it will start to slow down and what time this will finish.

Can anyone help?

Re: Daylight saving

Arunvijai_4 — Fri, 21 Oct 2005 04:47:39 GMT

Same question was floating here yesterday, you can find the answer here,

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=967177

-Arun

Re: Daylight saving

Muthukumar_5 — Fri, 21 Oct 2005 04:51:56 GMT

See man tztab man page.

You have to define time changes with /etc/tztab file so that it will get effective with date / ctime commands.

hth.

Re: Daylight saving

Muthukumar_5 — Fri, 21 Oct 2005 04:52:50 GMT

file is /usr/lib/tztab not /etc/tztab. (Bad day again to give correct information :( ).

thx.

Re: Daylight saving

MarkSyder — Fri, 21 Oct 2005 04:57:03 GMT

I think your understanding is incorrect: I don't believe the server slows down but switches to showing the amended time immediately it changes. In the UK this is 2 am.

Mark Syder (like the drink but spelt different)

Re: Daylight saving

Ravinder Singh Gill — Fri, 21 Oct 2005 05:01:20 GMT

This is what I need to confirm, whether it will slow down or whether it will change immediately & exactly at what time.

Are you guys sure it does not slow down?

Re: Daylight saving

Borislav Perkov — Fri, 21 Oct 2005 06:29:04 GMT

Hi Ravinger,

It will not slow. It will just change the time.

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=967177

Regards,
Borislav

Re: Daylight saving

Ravinder Singh Gill — Fri, 21 Oct 2005 09:10:20 GMT

Hi guys. You were right. from man tztab all is explained. The time changes from 01:59AM to 01:00AM.

Re: Daylight saving

John Waller — Fri, 21 Oct 2005 10:37:27 GMT

Ravinder,

Its not this weekend but next weekend 30th Oct
tztab: 0 1 25-31 10 1996-2038 0
Don't do what a collegue of mine once did, working on a Sunday morning he believed the time had changed and because all the servers were showing the wrong time manually changed them all (all 82 of them).

The problem was he then had to change them all back and because he had put the time forward 1 hour it caused problems with some of the application as it caused dusplicate data.

Re: Daylight saving

Ravinder Singh Gill — Fri, 21 Oct 2005 10:58:16 GMT

Thanks

Re: Daylight saving

Bill Thorsteinson — Fri, 21 Oct 2005 11:25:04 GMT

Time on the server will not change,
it is in UTC (aka GMT, or Zulu).
This timezone does not have daylight time.

Displayed times will change according to the timezone definition. Most definitions change
the time at 2 am (North America or 1 am
(Europe) as per the defined standard.
Using North America the next miniute after
1:59 xDT is 1:00 xST in faall and 3:00 xST
in spring.

More explanation about daylight saving is at:
http://webexhibits.org/daylightsaving/index.html