UTC Time setting? - Unix

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  1. UTC Time setting?

    Quick question -

    For a UNIX server, is it better to set my HW Clock to UTC time?


  2. Re: UTC Time setting?

    as400 wrote:
    >
    > For a UNIX server, is it better to set my HW Clock to UTC time?


    For most of the existance of UNIX times have used UTC and a
    timezone offset. The epoch in UNIX is defined as the first second
    of 1970 UTC.

    So I suspect your question is more about how to set up timezones
    than whether you should follow the standard of using GMT.


  3. Re: UTC Time setting?

    Begin <1137428956.193418.192800@g49g2000cwa.googlegroups. com>
    On 2006-01-16, as400 wrote:
    > For a UNIX server, is it better to set my HW Clock to UTC time?


    Yes. The usual way to run unices is to have the system clock set to UTC
    and then have a timezone locale indicate how much date(1) and assorted
    libc functions have to adjust the time displayed for local time.

    On x86 boxen[1] there's the system clock and an RTC that keeps the time
    while the box is turned off. It is customary for the RTC to also run
    UTC, but at least most free unices allow you to run it at local time
    then adjust the time used to initialize the system clock back to UTC at
    boot. This to allow for broken micros~1 software interoperability in
    multi-boot setups.


    [1] Don't know many details of other platforms' timekeeping, except that it
    might be different and will easily be less broken than the micros~1 way.

    --
    j p d (at) d s b (dot) t u d e l f t (dot) n l .
    This message was originally posted on Usenet in plain text.
    Any other representation, additions, or changes do not have my
    consent and may be a violation of international copyright law.

  4. Re: UTC Time setting?

    I am running Solaris (UNIX)....version 10...

    So how can I set my time to read UTC under the CDE desktop? Please
    explain. Where would I go to do that?

    Also,

    When I do a DATE -U command, the time comes back to a GMT time instead
    of UTC time...UTC time is more accurate than GMT and the term GMT is
    not used that often..So how can I set the date -u to read UTC instead
    of GMT?


  5. Re: UTC Time setting?

    as400 wrote:
    >
    > UTC time is more accurate than GMT


    Huh? They are alternate names for the same thing. Older
    and newer names for the standard time in the standard
    timezone.


  6. Re: UTC Time setting?

    "as400" writes:

    >I am running Solaris (UNIX)....version 10...


    >So how can I set my time to read UTC under the CDE desktop? Please
    >explain. Where would I go to do that?


    If you want to run the RTC clock in UTC, you will need to
    run "rtc_config" as root. (rtc_config -c -z UTC)

    You will then need to fix the clock, I think

    >Also,


    >When I do a DATE -U command, the time comes back to a GMT time instead
    >of UTC time...UTC time is more accurate than GMT and the term GMT is
    >not used that often..So how can I set the date -u to read UTC instead
    >of GMT?


    "UTC" is not more accurate in typical Unix speak (they're generally defined
    as being the same)

    Csper
    --
    Expressed in this posting are my opinions. They are in no way related
    to opinions held by my employer, Sun Microsystems.
    Statements on Sun products included here are not gospel and may
    be fiction rather than truth.

  7. Re: UTC Time setting?

    How can I change the CDE clock in Solaris 10 to show UTC..Thats what I
    need..I have asked this many times and know one knows...

    Is there an easy way to do this?

    I want my clock on my desktop to show as UTC..How can I do it?


  8. Re: UTC Time setting?

    Begin <1137437727.227055.101520@g49g2000cwa.googlegroups. com>
    On 2006-01-16, as400 wrote:
    > How can I change the CDE clock in Solaris 10 to show UTC..Thats what I
    > need..I have asked this many times and know one knows...


    No, you didn't quite ask that. Despite that, however, all the answers
    you've gotten hinted at the ways to do it. Since you asked in a unix
    administration group, it was assumed that you'd know at least basic
    administration skills and would be able to determine from what you were
    told how to do whatever it was that you wanted to do. That you can't,
    means that you're asking in the wrong group.

    To answer[1] what you have finally revealed to be your real question:
    The simplest way you can get UTC everywhere in your CDE is to set the
    TZ environment variable to UTC, and you can do that by putting

    TZ=UTC
    export TZ

    in your .profile file, if my guess that you're using a bourne or
    compatible shell as default shell. For other shells, adjust as needed.
    Then logout and login again. Enjoy.


    [1] With the caveat that I don't have sol10 here but FreeBSD 5.
    Corrections welcome, of course.

    --
    j p d (at) d s b (dot) t u d e l f t (dot) n l .
    This message was originally posted on Usenet in plain text.
    Any other representation, additions, or changes do not have my
    consent and may be a violation of international copyright law.

  9. Re: UTC Time setting?

    as400 wrote:
    >For a UNIX server, is it better to set my HW Clock to UTC time?


    1) there's no such thing as a UNIX server. Different specific systems
    may have different recommendations.

    2) most reasonable implementations have a way to specify what timezone the HW
    clock is in, and it's only used at boot anyway, so it doesn't matter to the
    system. It may be more convenient for the admin to have all machines using
    the same standard.
    --
    Mark Rafn dagon@dagon.net

  10. Re: UTC Time setting?

    On Tue, 17 Jan 2006 09:17:14 -0800, Mark Rafn wrote:
    > as400 wrote:
    >>For a UNIX server, is it better to set my HW Clock to UTC time?

    >
    > 1) there's no such thing as a UNIX server.


    There isn't? (glance) Hm. Wonder what all those noisy things over
    that way are then.

    > Different specific systems
    > may have different recommendations.


    I'm not aware of 'date' being functionally different in any varient of
    Unix.

  11. Re: UTC Time setting?

    In article <434o14F1km14iU2@individual.net>,
    Dave Hinz writes:
    > On Tue, 17 Jan 2006 09:17:14 -0800, Mark Rafn wrote:
    >> as400 wrote:
    >>>For a UNIX server, is it better to set my HW Clock to UTC time?

    >>
    >> 1) there's no such thing as a UNIX server.

    >
    > There isn't? (glance) Hm. Wonder what all those noisy things over
    > that way are then.
    >
    >> Different specific systems
    >> may have different recommendations.

    >
    > I'm not aware of 'date' being functionally different in any varient of
    > Unix.


    Perhaps he meant that UNIX isn't served? I did a double-take on that comment,
    too, and was wondering just what he had in mind.

    Stunned Ol' Bob (who has used UNIX servers for - gasp! - 30 years)


    --
    Robert G. Melson | Rio Grande MicroSolutions | El Paso, Texas
    -----
    "One of the greatest delusions in the world is the hope that the evils in this world are to be cured by legislation." Thomas Reed
    -----


  12. Re: UTC Time setting?

    On Wed, 18 Jan 2006 03:16:00 GMT, Robert Melson wrote:
    > In article <434o14F1km14iU2@individual.net>,
    > Dave Hinz writes:


    >> I'm not aware of 'date' being functionally different in any varient of
    >> Unix.

    >
    > Perhaps he meant that UNIX isn't served? I did a double-take on that comment,
    > too, and was wondering just what he had in mind.


    I _think_ it was a variation on the theme of "your question isn't
    specific enough to answer", except that it was.


  13. Re: UTC Time setting?

    Robert Melson wrote:
    >>> 1) there's no such thing as a UNIX server.

    >> There isn't? (glance) Hm. Wonder what all those noisy things over
    >> that way are then.


    They're probably some version of Solaris or Linux or AIX or something. 'Unix'
    is not a specific enough designation for some questions, including questions
    about hardware like the OP asked.

    >>> Different specific systems
    >>> may have different recommendations.


    >> I'm not aware of 'date' being functionally different in any varient of
    >> Unix.


    Nor am I, but the OP didn't ask about 'date', he asked whether the hardware
    clock in the machine should be set to UTC or local time. I probably should
    have said "whatever's more convenient for the admin" rather than trying to
    nudge the poster into realizing that the answer is specific to his system, not
    a general unix question.

    >Stunned Ol' Bob (who has used UNIX servers for - gasp! - 30 years).

    --
    Mark Rafn dagon@dagon.net

  14. Re: UTC Time setting?

    On Wed, 18 Jan 2006 10:43:34 -0800, Mark Rafn wrote:
    > Robert Melson wrote:
    >>>> 1) there's no such thing as a UNIX server.
    >>> There isn't? (glance) Hm. Wonder what all those noisy things over
    >>> that way are then.

    >
    > They're probably some version of Solaris or Linux or AIX or something. 'Unix'
    > is not a specific enough designation for some questions, including questions
    > about hardware like the OP asked.


    'man date' is as specific of an answer as was needed, for any Unix.

    >>> I'm not aware of 'date' being functionally different in any varient of
    >>> Unix.

    >
    > Nor am I, but the OP didn't ask about 'date', he asked whether the hardware
    > clock in the machine should be set to UTC or local time.


    And how could the flavor of Unix he's running possibly change the
    answer?

  15. Re: UTC Time setting?

    On 2006-01-18, Dave Hinz wrote:
    > On Wed, 18 Jan 2006 10:43:34 -0800, Mark Rafn wrote:
    >> Robert Melson wrote:


    >>>> I'm not aware of 'date' being functionally different in any varient of
    >>>> Unix.

    >>
    >> Nor am I, but the OP didn't ask about 'date', he asked whether the hardware
    >> clock in the machine should be set to UTC or local time.

    >
    > And how could the flavor of Unix he's running possibly change the
    > answer?


    On _some_, set to UTC is the only way it'll work right. On others it's
    possible to choose with no major difference in end-user functionality.

    Sure, you could say that it should be set to UTC and be done with it,
    but ...


    --
    Mikko Nahkola
    #include
    #Not speaking for my employer. No warranty. YMMV.

  16. Re: UTC Time setting?

    Dave Hinz wrote:
    > Mark Rafn wrote:
    >
    > > Nor am I, but the OP didn't ask about 'date', he asked whether the hardware
    > > clock in the machine should be set to UTC or local time.

    >
    > And how could the flavor of Unix he's running possibly change the
    > answer?


    The UNIX standard is for time to be in UTC and that standard is
    continued in UNIX-like systems that don't get to use the
    trademark.

    So for any single-boot variation of any type the hardware clock
    should be set using UTC. That leaves multi-boot hardware.
    While you could potentially have AIX/Linux, HPUX/Linux,
    Tru64/VMS/Linux systems by and large those are done with
    some type of hardware partitioning or emulation method not
    multi-boot. That leaves Intel hardware as the multi-boot ones.

    On Intel hardware it's a judgement call. UNIX standard is UTC
    with timezones to show the local time. Windows standard
    (I think) is to use local time and understand timezones to be
    able to deal with remote hosts. So which is easier - Use local
    time for both and adjust on the UNIX side or use UTC for both
    and adjust on the Windows side? Being a UNIX guy I know
    more about doing adjustments on the UNIX end so I would tend
    to give the Windows side the simple stuff. Were I a Windows
    guy I might choose the reverse.


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