topic Re: NTP Timezone in Operating System - HP-UX

NTP Timezone

j773303 — Thu, 17 Jul 2003 00:48:13 GMT

How to define the TIMEZONE for NTP ?
What's the difference EAT-8 and CST6CDT?

Re: NTP Timezone

Bill Hassell — Thu, 17 Jul 2003 01:06:00 GMT

NTP (ike most Unix flavors) have only ONE timezone: GMT or the more modern term UTC (Universal Coordinated Time) or Zulu. NTP keeps the Unix timeclock accurate to within 128ms of Zulu time. Timezones are political, not astrometrical so Unix allows every user to define their own representation for local time. This is done through the TZ environmental variable and can be changed at will for a given session. TZ is normally set in /etc/profile (from the file: /etc/TIMEZONE) and for international logins, changed to match the local time.

All the definitions for each TZ value are in the file: /usr/lib/tztab and of course the man page for tztab will help.

One nit: for programs (typically some daemons) that do not define or inherit the TZ environment value, the HP-UX system calls for time-of-day are adjusted with the kernel parameters timezone and dst. This is a much more crude method (minutes east/west of the Greenwich meridian) as it does not have the dozen of more variations for daylight saving.

Re: NTP Timezone

Steven E. Protter — Thu, 17 Jul 2003 01:07:06 GMT

Timezone is not defined in ntp.

You set your timezone in /etc/TIMZONE

mine looks like this:

TZ=CST6CDT
export TZ

Central time btw.

ntp just points to the server to get time from. It doesn't matter where it is. The system adjusted the time to fit your timezone.

SEP

Re: NTP Timezone

Michael Tully — Thu, 17 Jul 2003 01:08:15 GMT

I'm assuming your in China ??

Then your zone is -8 being 8 hours ahead of GMT (0 hours).
CST6CDT is central canadian time. 6 hours behind GMT.

As far as I know NTP does not have a definition for timezones.

Re: NTP Timezone

A. Clay Stephenson — Thu, 17 Jul 2003 02:03:07 GMT

To add to this, in a very real sense there is no such thing as a system-wide timezone. Of course, there is a default TZ but TZ can be set for each user or even each process. It is perfectly normal for users to have different timezone settings on the same server. After all, remote users might be logged in remotely from thousands of miles away. All UNIX boxes simply count seconds from 00:00 UTC 1-Jan-1970.
Timezone settings only affect how time is displayed. The chief effect of the system-wide timezone setting in /etc/TIMEZONE is that it is used as a default for processes like crond.

Re: NTP Timezone

Patrick Wallek — Thu, 17 Jul 2003 03:10:06 GMT

Umm...Michael, CST6CDT is Central Standard Time / Central Daylight Time and is in use in the whole of North America (US and Canada). ;)

Re: NTP Timezone

Patrick Wallek — Thu, 17 Jul 2003 03:11:24 GMT

Umm...Michael, CST6CDT is Central Standard Time / Central Daylight Time and is in use regiionally in the whole of North America (US and Canada). ;)

Re: NTP Timezone

Suresh Patoria — Thu, 17 Jul 2003 04:43:36 GMT

Hi,

You define the timezone in /etc/TIMEZONE file

and check the timezone using the command echo $TZ

Re: NTP Timezone

Suresh Patoria — Thu, 17 Jul 2003 04:45:19 GMT

Hi,

You define the timezone in /etc/TIMEZONE file

and check the timezone using the command echo $TZ