Hardy Heron daylight savings time - Ubuntu

This is a discussion on Hardy Heron daylight savings time - Ubuntu ; I have Windows XP running Sun xVM Virtual machine with Hardy Heron and the time is an hour later than it should be. I have the correct time zone selected and I have ntp running and I have done some ...

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  1. Hardy Heron daylight savings time

    I have Windows XP running Sun xVM Virtual machine with Hardy Heron and the
    time is an hour later than it should be. I have the correct time zone
    selected and I have ntp running and I have done some research and this
    seems to be a known problem but I have not been able to find a resolution.
    Does anybody here have a solution?

    Thanks,

    fybar

  2. Re: Hardy Heron daylight savings time

    fybar lothgorian wrote:

    > I have Windows XP running Sun xVM Virtual machine with Hardy Heron and the
    > time is an hour later than it should be. I have the correct time zone
    > selected and I have ntp running and I have done some research and this
    > seems to be a known problem but I have not been able to find a resolution.
    > Does anybody here have a solution?


    Linux expects your hardware clock to run on UTC. I guess your virtual
    machine's clock runs on local time, so you have to use UTC as your
    time zone. Run
    sudo dpkg-reconfigure tzdata
    in an terminal window . You'll find UTC in the "Geographic area" Etc.


    Florian
    --

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  3. Re: Hardy Heron daylight savings time

    On Sat, 11 Oct 2008 03:52:21 +0000, fybar lothgorian wrote:

    > I have Windows XP running Sun xVM Virtual machine with Hardy Heron and
    > the time is an hour later than it should be. I have the correct time
    > zone selected and I have ntp running and I have done some research and
    > this seems to be a known problem but I have not been able to find a
    > resolution. Does anybody here have a solution?


    Whether you should be in Daylight savings now depends on where you are.
    It may or may not be relevant, but I ran 'kdeusdo adept_updater' about a
    week ago and one of the things it downloaded was a new set of timezone
    rules.

  4. Re: Hardy Heron daylight savings time

    On Sat, 11 Oct 2008, in the Usenet newsgroup alt.os.linux.ubuntu, in article
    , fybar lothgorian wrote:

    >I have Windows XP running Sun xVM Virtual machine with Hardy Heron
    >and the time is an hour later than it should be.


    The time displayed where? Find a terminal, and run the commands

    date
    date -u

    The second command should show UTC (formally spoken of as GMT). The IP
    address you posted from seems to be in Edmonton, which should be six
    hours behind UTC (until 8 November, when it switches to seven hours).

    If UTC/GMT is correct and local time is not, then your zone files are
    in error - which seems unlikely as the latest change effecting Edmonton
    was made in June 2006 in tzdata2006.c. If both UTC and local time is
    incorrect by one hour, your clock setting configuration is incorrect.
    As you are running a virtual machine, the access to the hardware clock
    (normally used to initially set the clock) may be a problem. Note also
    that time-keeping on a virtual machine is subject to wild drift rates
    due to the lack of access to hardware interrupts which are (poorly)
    emulated.

    >I have the correct time zone selected and I have ntp running and I
    >have done some research and this seems to be a known problem but I
    >have not been able to find a resolution.


    If you have done the research, you'd know that NTP only deals in UTC
    and has no concept of timezone, much less daylight savings time. Note
    also that NTP normally won't try to correct a clock that is more than
    a few minutes in error. You say the zone selected is correct, but which
    zone is it? From your posting address, this would be America/Edmonton.

    But all of this goes back to the question of where are you looking and
    seeing this time error? Is this some eye-candy clock on your windoze
    desktop? File timestamps? Or what?

    Old guy

  5. Re: Hardy Heron daylight savings time

    On Sat, 11 Oct 2008, in the Usenet newsgroup alt.os.linux.ubuntu, in article
    <8sednViSf8d8a23VnZ2dnUVZ_sPinZ2d@posted.cavenetllc>, Roland Latour wrote:

    >Whether you should be in Daylight savings now depends on where you are.
    >It may or may not be relevant, but I ran 'kdeusdo adept_updater' about a
    >week ago and one of the things it downloaded was a new set of timezone
    >rules.


    Looking at the source (ftp://elsie.nci.nih.gov/pub/), the tz files were
    updated last Monday, but the changes from tzdata2008f (Sep 15) to
    tzdata2008g only effect DST ending dates in Brazil. The last changes to
    effect North American users occurred in March, and that only referred
    to DST dates in Cuba. The last change effecting Canadian or US residents
    occurred in tzdata2007g about 14 months ago.

    Old guy

  6. Re: Hardy Heron daylight savings time

    On Sat, 11 Oct 2008, in the Usenet newsgroup alt.os.linux.ubuntu, in article
    , Florian Diesch wrote:

    >Linux expects your hardware clock to run on UTC.


    This has never been the case. 'man hwclock' and look at the --utc
    option, which says:

    --utc Indicates that the Hardware Clock is kept in Coordinated
    Universal Time. It is your choice whether to keep your
    clock in UTC or local time, but nothing in the clock tells
    which you've chosen. So this option is how you give that
    information to hwclock.

    If you don't specify --utc when you should, or vice versa, both
    setting and querying of the Hardware Clock will be messed up.

    The reason that Linux can accept the hardware clock running on "local"
    time is the a lot of users dual-boot into windoze (which being a single
    user operating system sees no need to know about anything other than
    the local time). Here, note that if you DON'T specify the --utc
    option, /sbin/hwclock assumes the hardware clock to be in local time.
    Setting the hardware clock to UTC may be the _preferred_ choice, but
    it's definitely NOT mandatory.

    Note also that the hardware clock is only used to _SET_ the system
    clock at boot. For all other uses, the system clock (a software
    time kept by the O/S) is used. This is what you see when using the
    'date' command. Virtual systems on x86 style hardware may be lousy
    time-keepers, as system time depends on counting IRQ 0 interrupts,
    which can be easily missed in a virtual machine.

    If you look at your system boot scripts, the first one run (rc.sysinit
    in a SysVInit style setup) checks some file in /etc (such as
    /etc/sysconfig/clock in some distributions) to determine which the
    clock is set to - local or UTC.

    Old guy

  7. Re: Hardy Heron daylight savings time

    ibuprofin@painkiller.example.tld (Moe Trin) wrote in
    news:slrngf2ehh.m09.ibuprofin@compton.phx.az.us:

    > On Sat, 11 Oct 2008, in the Usenet newsgroup alt.os.linux.ubuntu, in
    > article , fybar
    > lothgorian wrote:
    >
    >>I have Windows XP running Sun xVM Virtual machine with Hardy Heron
    >>and the time is an hour later than it should be.

    >
    > The time displayed where? Find a terminal, and run the commands
    >
    > date
    > date -u


    This is just for a desktop clock, Linux desktop that is.
    fybar@fybar-desktop:/$ date
    Sun Oct 12 13:11:23 MDT 2008
    fybar@fybar-desktop:/$ date -u
    Sun Oct 12 19:11:25 UTC 2008

    Actual Daylight Savings Time time is 12:11:27, one hour difference.

    -snip-

    >>I have the correct time zone selected and I have ntp running and I
    >>have done some research and this seems to be a known problem but I
    >>have not been able to find a resolution.

    >
    > If you have done the research, you'd know that NTP only deals in UTC
    > and has no concept of timezone, much less daylight savings time. Note
    > also that NTP normally won't try to correct a clock that is more than
    > a few minutes in error. You say the zone selected is correct, but
    > which zone is it? From your posting address, this would be
    > America/Edmonton.


    I am in Edmonton. I have set up NTP many times and I tried manually
    settting the clock to the correct time and then running NTP, which did
    not work upon a reboot of the guest OS. Yes, I know that NTP provides UTC
    and it is the OS on top of that that needs to display my preference for
    Daylight Savings Time. I included the NTP information so that you would
    know what I had configured. It seems as though my corrected for DST on
    windows is being taken as my hardware clock, which is an hour later and
    thus setting my guest os up an hour. Does Ubuntu require UTC time? Can I
    not just use the time Windows is supplying? I don't require NTP so am
    quite willing to abandon it.

    > But all of this goes back to the question of where are you looking and
    > seeing this time error? Is this some eye-candy clock on your windoze
    > desktop? File timestamps? Or what?
    >
    > Old guy


    Non-production. I am a FreeBSD guy and wanted to try something different
    so I am playing around with Ubuntu on a VM, though I wish I had a
    dedicated box for it. That will happen later when I have one to spare.

    Thank-you very much for the detailed reply. I like understanding what is
    going on under the hood as much as possible.

    fybar

  8. Re: Hardy Heron daylight savings time

    On Sun, 12 Oct 2008, in the Usenet newsgroup alt.os.linux.ubuntu, in article
    , fybar lothgorian wrote:

    >ibuprofin@painkiller.example.tld (Moe Trin) wrote


    >> date
    >> date -u

    >
    >This is just for a desktop clock, Linux desktop that is.
    >fybar@fybar-desktop:/$ date
    >Sun Oct 12 13:11:23 MDT 2008
    >fybar@fybar-desktop:/$ date -u
    >Sun Oct 12 19:11:25 UTC 2008
    >
    >Actual Daylight Savings Time time is 12:11:27, one hour difference.


    I'm confused. You're showing a six hour difference, and that's what
    timezone files say you should see.

    [compton ~]$ /usr/sbin/zdump -v America/Edmonton | grep 2008
    America/Edmonton Sun Mar 9 08:59:59 2008 GMT = Sun Mar 9 01:59:59
    2008 MST isdst=0
    America/Edmonton Sun Mar 9 09:00:00 2008 GMT = Sun Mar 9 03:00:00
    2008 MDT isdst=1
    America/Edmonton Sun Nov 2 07:59:59 2008 GMT = Sun Nov 2 01:59:59
    2008 MDT isdst=1
    America/Edmonton Sun Nov 2 08:00:00 2008 GMT = Sun Nov 2 01:00:00
    2008 MST isdst=0
    [compton ~]$ date -u
    Sun Oct 12 22:34:11 UTC 2008
    [compton ~]$ /usr/sbin/zdump America/Edmonton
    America/Edmonton Sun Oct 12 16:34:16 2008 MDT
    [compton ~]$

    Six hours. ???

    >I am in Edmonton.


    And that's what I'm testing to. I don't see the problem with the
    zonetime. What _MAY_ be the problem is your idea of UTC..

    >I have set up NTP many times and I tried manually settting the clock
    >to the correct time and then running NTP, which did not work upon a
    >reboot of the guest OS. Yes, I know that NTP provides UTC and it is
    >the OS on top of that that needs to display my preference for Daylight
    >Savings Time. I included the NTP information so that you would know
    >what I had configured. It seems as though my corrected for DST on
    >windows is being taken as my hardware clock, which is an hour later
    >and thus setting my guest os up an hour.


    Do you have /sbin/hwclock installed (or any similar tool that reads the
    hardware clock directly)?

    [compton ~]$ date -u ; /sbin/hwclock -r
    Sun Oct 12 22:36:05 UTC 2008
    Sun Oct 12 22:36:06 2008 -0.596022 seconds
    [compton ~]$

    I'm not sure where a one hour difference could come in - you're in
    Edmonton, which the zonefile says is six hours away from UTC.

    >Does Ubuntu require UTC time? Can I not just use the time Windows is
    >supplying? I don't require NTP so am quite willing to abandon it.


    Ubuntu (or any Linux) requires _EITHER_ UTC or Localtime. It merely
    has to know which the time is. The problems occur when the clock is
    set to neither UTC or Localtime. Then stuff gets hairy, but that's
    true on all O/S.

    >Non-production. I am a FreeBSD guy and wanted to try something
    >different so I am playing around with Ubuntu on a VM, though I wish
    >I had a dedicated box for it. That will happen later when I have one
    >to spare.


    Virtual machines are not always optimum.

    Old guy

  9. Re: Hardy Heron daylight savings time

    fybar lothgorian schrieb:
    > I have Windows XP running Sun xVM Virtual machine with Hardy Heron and the
    > time is an hour later than it should be. I have the correct time zone
    > selected and I have ntp running and I have done some research and this
    > seems to be a known problem but I have not been able to find a resolution.
    > Does anybody here have a solution?
    >
    > Thanks,
    >
    > fybar


    I' d suggest you to set one timezone later. I' ve done that with my PC,
    too, and I don' t see any reason, why not to...

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