Daylight saving come up soon

Discussion in 'Java' started by Roedy Green, Mar 7, 2008.

  1. Roedy Green

    Roedy Green Guest

    For North Americans daylight saving starts Sunday March 9.

    On daylight saving switch days, don’t set your computer clock forward
    an hour! Instead, make sure your machine is configured to the correct
    time zone, and reset your clock from an atomic time source. It will
    automatically jump at 2 AM. If you fiddle the clock, you will screw up
    the file timestamps which are kept in timezone-independent,
    DST-independent, GMT aka UTC. To make sure your timezone is
    configured correctly, and to set your clock from an atomic timesource,
    use the SetClock utility. http://mindprod.com/webstart/setclock.html


    It works only for windows. With a tiny bit of JNI it would also work
    on other platforms. Hint Hint.

    For background see:

    http://mindprod.com/jgloss/dst.html
    http://mindprod.com/jgloss/timezone.html
    http://mindprod.com/jgloss/timesources.html


    --

    Roedy Green Canadian Mind Products
    The Java Glossary
    http://mindprod.com
     
    Roedy Green, Mar 7, 2008
    #1
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  2. Roedy Green

    Nigel Wade Guest

    Roedy Green wrote:

    >
    > It works only for windows. With a tiny bit of JNI it would also work
    > on other platforms.


    Other platforms don't need hackery to the system clock to deal with DST. Only
    Microsoft/Windows is daft enough to operate in wall-clock time.

    > Hint Hint.
    >


    Quite.

    --
    Nigel Wade, System Administrator, Space Plasma Physics Group,
    University of Leicester, Leicester, LE1 7RH, UK
    E-mail :
    Phone : +44 (0)116 2523548, Fax : +44 (0)116 2523555
     
    Nigel Wade, Mar 7, 2008
    #2
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  3. On Fri, 07 Mar 2008 09:59:22 GMT, Roedy Green wrote:
    > It works only for windows. With a tiny bit of JNI it would also work
    > on other platforms. Hint Hint.


    Other platforms use ntp.

    /gordon

    --
     
    Gordon Beaton, Mar 7, 2008
    #3
  4. Gordon Beaton, 07.03.2008 12:19:
    > On Fri, 07 Mar 2008 09:59:22 GMT, Roedy Green wrote:
    >> It works only for windows. With a tiny bit of JNI it would also work
    >> on other platforms. Hint Hint.

    >
    > Other platforms use ntp.
    >

    Windows has ntp as well.
     
    Thomas Kellerer, Mar 7, 2008
    #4
  5. Nigel Wade wrote:
    > Roedy Green wrote:
    >
    >> It works only for windows. With a tiny bit of JNI it would also work
    >> on other platforms.

    >
    > Other platforms don't need hackery to the system clock to deal with DST. Only
    > Microsoft/Windows is daft enough to operate in wall-clock time.


    Current versions of Windows use UTC internally.

    Windows 9x and ME are not supported anymore.

    Mark Thornton
     
    Mark Thornton, Mar 7, 2008
    #5
  6. Roedy Green

    Roedy Green Guest

    On Fri, 07 Mar 2008 10:52:17 +0000, Nigel Wade <>
    wrote, quoted or indirectly quoted someone who said :

    >Other platforms don't need hackery to the system clock to deal with DST. Only
    >Microsoft/Windows is daft enough to operate in wall-clock time.


    I believe NT, 2000 and Vista all work internally on GST/UTC. They
    will automatically handle DST. All you need do is ensure the timezone
    is correctly configured and the UTC base time is correct.
    Previously they worked on raw wall clock time.
    --

    Roedy Green Canadian Mind Products
    The Java Glossary
    http://mindprod.com
     
    Roedy Green, Mar 7, 2008
    #6
  7. Roedy Green

    Roedy Green Guest

    On Fri, 07 Mar 2008 13:13:34 +0100, Thomas Kellerer
    <> wrote, quoted or indirectly quoted
    someone who said :

    >Windows has ntp as well.


    It does not seem to work. I think the problem is MS has only one time
    server, and it is too busy.

    I use the Windows NTP, SetClock
    http://mindprod.com/jgloss/webstart/setclock.html
    and double check everything with radio controlled "atomic" clock on my
    desk. see http://mindprod.com/jgloss/radiosynchedclock.html
    http://mindprod.com/jgloss/bgloss/wallclock.html


    --

    Roedy Green Canadian Mind Products
    The Java Glossary
    http://mindprod.com
     
    Roedy Green, Mar 7, 2008
    #7
  8. Roedy Green

    Jeff Higgins Guest

    Roedy Green wrote:
    > On Fri, 07 Mar 2008 13:13:34 +0100, Thomas Kellerer
    > <> wrote, quoted or indirectly quoted
    > someone who said :
    >
    >>Windows has ntp as well.

    >
    > It does not seem to work. I think the problem is MS has only one time
    > server, and it is too busy.


    Change the server?

    >
    > I use the Windows NTP, SetClock
    > http://mindprod.com/jgloss/webstart/setclock.html
    > and double check everything with radio controlled "atomic" clock on my
    > desk. see http://mindprod.com/jgloss/radiosynchedclock.html
    > http://mindprod.com/jgloss/bgloss/wallclock.html
    >
    >
     
    Jeff Higgins, Mar 7, 2008
    #8
  9. Roedy Green

    Roedy Green Guest

    On Fri, 7 Mar 2008 18:43:02 -0500, "Jeff Higgins"
    <> wrote, quoted or indirectly quoted someone who
    said :

    >> It does not seem to work. I think the problem is MS has only one time
    >> server, and it is too busy.

    >
    >Change the server?


    I don't think you can. It is built-in to Vista.
    --

    Roedy Green Canadian Mind Products
    The Java Glossary
    http://mindprod.com
     
    Roedy Green, Mar 7, 2008
    #9
  10. Roedy Green

    Arne Vajhøj Guest

    Roedy Green wrote:
    > For North Americans daylight saving starts Sunday March 9.
    >
    > On daylight saving switch days, don’t set your computer clock forward
    > an hour! Instead, make sure your machine is configured to the correct
    > time zone, and reset your clock from an atomic time source. It will
    > automatically jump at 2 AM. If you fiddle the clock, you will screw up
    > the file timestamps which are kept in timezone-independent,
    > DST-independent, GMT aka UTC. To make sure your timezone is
    > configured correctly, and to set your clock from an atomic timesource,
    > use the SetClock utility. http://mindprod.com/webstart/setclock.html
    >
    >
    > It works only for windows. With a tiny bit of JNI it would also work
    > on other platforms. Hint Hint.


    I can not see any point in this utility.

    Windows changes DST automatically and has done so for
    many years.

    Arne
     
    Arne Vajhøj, Mar 8, 2008
    #10
  11. Roedy Green

    Arne Vajhøj Guest

    Roedy Green wrote:
    > On Fri, 7 Mar 2008 18:43:02 -0500, "Jeff Higgins"
    > <> wrote, quoted or indirectly quoted someone who
    > said :
    >>> It does not seem to work. I think the problem is MS has only one time
    >>> server, and it is too busy.

    >> Change the server?

    >
    > I don't think you can. It is built-in to Vista.


    net time /set /yes

    should be able to set the time from a time server (not necessarily
    Windows based) on the network.

    Arne
     
    Arne Vajhøj, Mar 8, 2008
    #11
  12. Roedy Green

    Peter Duniho Guest

    On Fri, 07 Mar 2008 15:50:01 -0800, Roedy Green
    <> wrote:

    >>> It does not seem to work. I think the problem is MS has only one time
    >>> server, and it is too busy.

    >>
    >> Change the server?

    >
    > I don't think you can. It is built-in to Vista.


    Granted, I haven't used Vista on a regular basis. But looking at, for
    example, this page --
    http://www.howtogeek.com/howto/windows-vista/dealing-with-windows-vista-time-sync-problems/
    -- it appears to me that the Vista Internet Time UI is exactly the same as
    it was in XP.

    You can type the name of whatever server you want into the control.

    A good thing for people to remember: "just because you hate Windows, that
    doesn't mean you have a clue about how it works".

    Pete
     
    Peter Duniho, Mar 8, 2008
    #12
  13. Roedy Green

    Jeff Higgins Guest

    Roedy Green wrote:
    > On Fri, 7 Mar 2008 18:43:02 -0500, "Jeff Higgins"
    > <> wrote, quoted or indirectly quoted someone who
    > said :
    >
    >>> It does not seem to work. I think the problem is MS has only one time
    >>> server, and it is too busy.

    >>
    >>Change the server?

    >
    > I don't think you can. It is built-in to Vista.


    Sure you can;
    <http://preview.tinyurl.com/33gdvk>
    keeping in mind;
    <http://preview.tinyurl.com/33fpso>
     
    Jeff Higgins, Mar 8, 2008
    #13
  14. Roedy Green

    Roedy Green Guest

    On Fri, 7 Mar 2008 19:27:22 -0500, "Jeff Higgins"
    <> wrote, quoted or indirectly quoted someone who
    said :

    >> I don't think you can. It is built-in to Vista.

    >
    >Sure you can;
    ><http://preview.tinyurl.com/33gdvk>
    >keeping in mind;
    ><http://preview.tinyurl.com/33fpso>


    thanks. I have added those links to
    http://mindprod.com/jgloss/vista.html
    --

    Roedy Green Canadian Mind Products
    The Java Glossary
    http://mindprod.com
     
    Roedy Green, Mar 8, 2008
    #14
  15. Roedy Green

    Roedy Green Guest

    On Fri, 07 Mar 2008 19:08:18 -0500, Arne Vajhøj <>
    wrote, quoted or indirectly quoted someone who said :

    >I can not see any point in this utility.
    >
    >Windows changes DST automatically and has done so for
    >many years.


    But it doesn't work reliably. Try setclock and you will see.
    --

    Roedy Green Canadian Mind Products
    The Java Glossary
    http://mindprod.com
     
    Roedy Green, Mar 8, 2008
    #15
  16. Roedy Green

    Roedy Green Guest

    On Sat, 08 Mar 2008 09:04:12 GMT, Roedy Green
    <> wrote, quoted or indirectly quoted
    someone who said :

    >>Windows changes DST automatically and has done so for
    >>many years.

    >
    >But it doesn't work reliably. Try setclock and you will see.


    IF you have the timezone configured, it does the DST flip if you have
    the latest updates installed. On some Windows it is a manual update
    to deal with the change in rules.

    However, I could never get the auto NTS update to work with the MS
    time server. I will try it with another. My time would drift many
    seconds off.
    --

    Roedy Green Canadian Mind Products
    The Java Glossary
    http://mindprod.com
     
    Roedy Green, Mar 8, 2008
    #16
  17. Roedy Green wrote:
    > On Sat, 08 Mar 2008 09:04:12 GMT, Roedy Green
    > <> wrote, quoted or indirectly quoted
    > someone who said :
    >
    >>> Windows changes DST automatically and has done so for
    >>> many years.

    >> But it doesn't work reliably. Try setclock and you will see.

    >
    > IF you have the timezone configured, it does the DST flip if you have
    > the latest updates installed. On some Windows it is a manual update
    > to deal with the change in rules.
    >
    > However, I could never get the auto NTS update to work with the MS
    > time server. I will try it with another. My time would drift many
    > seconds off.


    There are advantages to being free from the Dark Side. I've run ntp for
    years on my Linux systems, My internet time sources are the European and
    Pacific timeserver pools and, a historic hang-over from my dial-up days
    and RedHat 6.2, I have a home built receiver for the Rugby MSF time
    signal configured as a tier 2 source.

    Jonathon Buzzard designed the hardware and wrote a shared-memory ntpd
    interface for it. The hardware cost GBP 30 ($US 60) and took barely a
    couple of hours to assemble and test. Its powered from the serial port.
    See http://www.buzzard.me.uk/jonathan/radioclock.html for details.


    --
    martin@ | Martin Gregorie
    gregorie. | Essex, UK
    org |
     
    Martin Gregorie, Mar 8, 2008
    #17
  18. In comp.lang.java.programmer message <rb22t3hh8skch17as5jn922ae19a79e159
    @4ax.com>, Fri, 7 Mar 2008 09:59:22, Roedy Green <
    om.invalid> posted:
    >For North Americans daylight saving starts Sunday March 9.
    >
    >On daylight saving switch days, don’t set your computer clock forward
    >an hour! Instead, make sure your machine is configured to the correct
    >time zone, and reset your clock from an atomic time source. It will
    >automatically jump at 2 AM.


    Some North Americans do not have Summer Time.

    NRC thinks that Newfoundland changes at 00:01 clock time (which IMHO
    gives a risk of advancing the date, in Autumn, twice).

    I believe that Mexico is in North America, and uses different dates.
    I believe that Greenland is in North America, and uses different dates.

    <http://www.worldtimezone.com/daylight.htm>.

    Caveat : I think they are inaccurate about Europe, in that there are
    non-EU non-Russian parts of Europe which follow the Russian times.

    --
    (c) John Stockton, nr London, UK. ?@merlyn.demon.co.uk Turnpike v6.05 MIME.
    Web <URL:http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
    Proper <= 4-line sig. separator as above, a line exactly "-- " (SonOfRFC1036)
    Do not Mail News to me. Before a reply, quote with ">" or "> " (SonOfRFC1036)
     
    Dr J R Stockton, Mar 8, 2008
    #18
  19. Roedy Green

    Karl Guest

    "Martin Gregorie" <> wrote in message
    news:...
    > Roedy Green wrote:
    >> On Sat, 08 Mar 2008 09:04:12 GMT, Roedy Green
    >> <> wrote, quoted or indirectly quoted
    >> someone who said :
    >>
    >>>> Windows changes DST automatically and has done so for
    >>>> many years.
    >>> But it doesn't work reliably. Try setclock and you will see.

    >>
    >> IF you have the timezone configured, it does the DST flip if you have
    >> the latest updates installed. On some Windows it is a manual update
    >> to deal with the change in rules.
    >>
    >> However, I could never get the auto NTS update to work with the MS
    >> time server. I will try it with another. My time would drift many
    >> seconds off.

    >
    > There are advantages to being free from the Dark Side. I've run ntp for
    > years on my Linux systems, My internet time sources are the European and
    > Pacific timeserver pools and, a historic hang-over from my dial-up days
    > and RedHat 6.2, I have a home built receiver for the Rugby MSF time signal
    > configured as a tier 2 source.
    >
    > Jonathon Buzzard designed the hardware and wrote a shared-memory ntpd
    > interface for it. The hardware cost GBP 30 ($US 60) and took barely a
    > couple of hours to assemble and test. Its powered from the serial port.
    > See http://www.buzzard.me.uk/jonathan/radioclock.html for details.


    I have never had problems with any Windows NT-based system including, NTP,
    DST, time zones, etc.

    I have a Java weather data acquisition application that I happen to be
    running on Windows XP, and it sails right through DST time changes with no
    trouble at all, and stays synchronized with time.windows.com or any other
    NTP server I happen to choose.

    http://mysite.verizon.net/Karl_Uppiano/weather.html
    http://mysite.verizon.net/Karl_Uppiano/wxservice.html

    There are minor difficulties if the hardware timebase is not accurate,
    causing wind speed anomalies when it syncs with network time, but that isn't
    Windows' fault.
     
    Karl, Mar 9, 2008
    #19
  20. Dr J R Stockton wrote:
    > In comp.lang.java.programmer message <rb22t3hh8skch17as5jn922ae19a79e159
    > @4ax.com>, Fri, 7 Mar 2008 09:59:22, Roedy Green <
    > om.invalid> posted:
    >> For North Americans daylight saving starts Sunday March 9.

    >
    > Some North Americans do not have Summer Time.
    >
    > NRC thinks that Newfoundland changes at 00:01 clock time (which IMHO
    > gives a risk of advancing the date, in Autumn, twice).
    >
    > I believe that Mexico is in North America, and uses different dates.
    > I believe that Greenland is in North America, and uses different dates.


    He probably just meant USA and Canada.

    Arne
     
    Arne Vajhøj, Mar 9, 2008
    #20
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