HP-UX and Time settings

[andy_197]

During the installation process of HP-UX, does the time automatically set itself to the UTC time format??


I heard that UNIX systems are set to UTC by default but I just want to confirm that.

[Sundar_7]

Andy,

It is not the HP-UX that keeps the time for you. It is the clock in the motherboard of your system that stores the time.

This topic has been discussed number of times.

All your system hardware clock does is to keep counting from Jan'1 1970. When you issue commands like date, for example, refers to the TZ environment variable and convert UTC to the corresponding local time using the /usr/lib/tztab table.

- Sundar

[A. Clay Stephenson]

When HP-UX is installed, you are prompted for the default timezone; this value is then stored in /etc/TIMEZONE. This file is used to set the default value for TZ. If TZ is not set then the kernel tunable 'timezone' comes into play. Bear in mind, a system might have several valid TZ settings at any one time --- users might be scattered across many timezones.

[Bill Hassell]

EVERY HP-UX system keeps time in UTC format. It is not a default, it is the way it operates. When you login. the 'translator' variable TZ is set by /etc/TIMEZONE as part of your login profile, so you see UTC translated by the TZ value. Read the contents of /usr/lib/tztab and the man page for tztab. You can create your own private timezone if you want. HP-UX is somewhat unique in being able to provide *every* timezone at the same time, and also handle any crazy rule about Daylight Saving time. But internally, HP-UX always keep UTC and never changes for Daylight Saving.

[andy_197]

So, just to confirm, does HP-UX manage time in UTC??

Because I heard that ALL UNIXs operates the "default" time format in UTC. But, my question is, if an HP-UX administrator DOES NOT select the Local Timezone (TZ) does that mean that it will automatically set the time in UTC by default?

Thanks

[Sridhar Bhaskarla]

Hi Andy,

The timezone variable "TZ" has nothing to do with how HP-UX keeps it's time. "TZ" variable is only for the interpretation of time. The default "TZ" is listed in /etc/TIMEZONE file. By default everyuser's TZ variable gets it. Generally to make more sense, SAs configure the TIMEZONE to where the systems are located. Some SAs tend to configure GMT if their systems in different locations to get a relative picture.

Default TZ can be overwritten by specifying the user's own Timezone in his/her .profile. For ex., as a user I can do

$export TZ=GMT
$date
$export TZ=CST6CDT
$date

-Sri

[Steven E. Protter]

Answer to your question.

Yes. It does keep time in UTC format. Its Unix.

SEP

;-)

[Bill Hassell]

When HP-UX is installed, you are asked about your location in order to set the TZ value. If your computer came preinstalled, then a default value for TZ was set (probably US-Mountain or US-Pacific). To set your default timezone, just run the program set_parms as root:

/sbin/set_parms timezone

That will set /etc/TIMEZONE and now each user that logs in will have the TZ value set for this location. As mentioned, TZ controls how time is displayed or provided to user programs. So someone from a different country can login to your system, export TZ in their current session and see their local time including timestamps on files (ls -l) as well as applicatins that are run from that session.

[Rick Garland]

You're right - all UNIX tracks time in UTC format. It is the variable TZ that converts the UTC to local time.