Re: Time Zone Change Question - Hewlett Packard

This is a discussion on Re: Time Zone Change Question - Hewlett Packard ; i believe the rate of change (how long it takes for t "it depends" :-) i believe the rate of change (how long it takes for time to become correct again) depends on the size box you're running. bigger boxes ...

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Thread: Re: Time Zone Change Question

  1. Re: Time Zone Change Question

    i believe the rate of change (how long it takes for t
    "it depends" :-)

    i believe the rate of change (how long it takes for time to become correct again) depends on the size box you're running. bigger boxes will become correct faster than slower. i don't remember if systemload plays a (significant) factor or not.

    the thing you should tell them is -- don't worry (i'd leave off 'be happy' :-). the 'fallback' process will not allow any time to be repeated. they should not have to make anychanges.

    the following is from help for 'setclock':

    Results of the Time Zone Form
    If the change in time zone is to a later time (a change to Daylight
    Savings Time or an "Eastern" geographic movement),both local time
    and the time zone offset are changed immediately.

    The effect is that users of local system time will see an immediate
    jump forward to the new time zone, while users of Universal Time
    will see no change.

    If the change in time zone is to an earlier time (a change from
    Daylight Savings to Standard Time or a "Western" geographic
    movement), the time zone offset is changed immediately. Then the
    local time slows down until the system time corresponds to the
    time in the new time zone.

    The effect is that users of local system time will see a gradual
    slowdown to match the new time zone, while users of Universal Time
    will see an immediate forward jump, then a slowdown until the
    system time again matches "real" Universal Time.

    This method of changing time zones ensures that no out-of-sequence <<<<
    time stamps will occur either in localtime or in Universal Time. <<<<

    mpe is what unix hopes tobe when it grows up ;-) - d

    ----
    Donna Hofmeister, HP-CSA Sr. System Programmer
    dgarverick -at- longs -dot- com
    925-210-6631 LongsDrug Stores

    >>>MY opinions, not Longs Drug Stores'<<<



    ----- Original Message ----
    From: Dan Barnes
    To: HP3000-L@RAVEN.UTC.EDU
    Sent: Wednesday, March 7, 2007 11:50:26 AM
    Subject: Re: [HP3000-L] Time Zone Change Question


    BTW, I should have beenmore specific and state that we use the SETCLOCK
    TIMEZONE=W6:00 when this is done.

    Dan Barnes
    LCI Offices
    106 Central Avenue, Suite A
    Osseo, MN, 55369-1243
    Tel: 763-425-1639 :: Fax: 763-425-5483
    Cell: 612-240-2136 :: Pager: 952-394-013
    dan.barnes@lci-online.com
    dpbarnes@mmm.com

    -----Original Message-----
    From: HP-3000 Systems Discussion [mailto:HP3000-L@RAVEN.UTC.EDU] On
    Behalf Of Dan Barnes
    Sent: Wednesday, March 07, 2007 1:48 PM
    To: HP3000-L@RAVEN.UTC.EDU
    Subject: [HP3000-L] TimeZone Change Question

    Hi -L Gang,

    I have searched but an unable to find an answer to the specific question
    of:

    When I change the timeBACKWARDS 1 hour in the Fall, how long does that
    change take.

    We have been asked by our apps folks how long it will take for the time
    to be
    adjusted in moving back one hour as they wish to adjust their
    procedures. I
    have not been given other specifics about what they want to do other
    than to
    get them an answer as to how long the change will take.

    TIA,
    Dan

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  2. Re: Time Zone Change Question

    Donna writes,

    [regarding the way MPE does gradual adjustments in such a way that
    neither system time nor UTC ever move backward]

    > mpe is what unix hopes to be when it grows up ;-) - d


    I'd love to agree with Donna's sentiment, but I'm afraid this is one
    area where Unix gets it right.

    In real life, local time DOES "fall backward." At 2:00 AM the time
    instantaneously becomes 1:00 AM again, and that's the way Unix behaves.

    Likewise, in real life, UTC never takes a giant leap forward.

    The gradual time adjustment that MPE does certainly has its advantages,
    especially for people who use the system time as a time stamp, but the
    Unix method more closely matches reality.

    Walter

    Walter J. Murray

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  3. Re: Time Zone Change Question

    Walter J. Murray wrote:
    > The gradual time adjustment that MPE does certainly has its advantages,
    > especially for people who use the system time as a time stamp, but the
    > Unix method more closely matches reality.


    SETCLOCK has the ;NOW option, if you need it immediately.

    Keven

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  4. Re: Time Zone Change Question

    Walter,

    now this is an interesting mental exorcise. The terms Reality and Day
    Light Savings Time adjustment.

    Since the values we assign time are purely our own, and time passes
    regardless of how we adjust our measuring stick. So reality is based on
    some political wind that blows a lot of hot air (based on the fact that
    Savings time requires law makers to enact it). ;-)

    Sorry, just couldn't resist picking on you this morning.


    Walter J. Murray wrote:
    >
    > In real life, local time DOES "fall backward." At 2:00 AM the time
    > instantaneously becomes 1:00 AM again, and that's the way Unix behaves.
    >
    > Likewise, in real life, UTC never takes a giant leap forward.
    >
    > The gradual time adjustment that MPE does certainly has its advantages,
    > especially for people who use the system time as a time stamp, but the
    > Unix method more closely matches reality.
    >
    >


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