Re: Time quandry when dual boot with WinXP Pro
On Sat, 22 Oct 2016 09:57:05 -0500
David Wright <deblis@lionunicorn.co.uk> wrote:
> On Fri 21 Oct 2016 at 18:47:43 (+0100), Joe wrote:
> > On Fri, 21 Oct 2016 09:58:42 -0500
> > David Wright <deblis@lionunicorn.co.uk> wrote:
> > >
> > > . Neither OS was running when Civil Time changed to/from DST,
> > > . After the time changed, one OS has run, updating the Local Time
> > > to match Civil Time, . Another OS is just being booted up.
> > >
> > > What Local Time will eventually be displayed by this system?
> > >
> > DST may well be the answer.
>
> (I can't see how that answers anything, as I hadn't specified which
> way time changed, nor can I see why it would be an answer in either
> case.)
>
> My concern is that the second OS to boot might apply the time change
> in exactly the same manner as the first one did and should have done.
> So the system's Local Time would end up an hour fast (were this late
> Spring) or slow (were this late Fall) after the second OS applied its
> own time change.
>
> Or IOW what mechanism is there for one OS to find out whether another
> OS has altered the RTC by an hour any time recently?¹
>
> > If I boot Linux on my Win8 laptop in the
> > summer, it knows the time perfectly well. If I now boot Win8, the
> > clock is an hour ahead. It does use a network time source but it
> > does not query the source on boot, or soon afterwards. Eventually
> > it will do so, but on a fixed schedule, so not for days, and there
> > seems to be no way to fix it. It's not just the first time after
> > DST arrives, it's every time.
>
> But isn't that just a configuration problem which I assume is unusual
> in that most people are not reporting that problem? What's more, you
> don't say whether your RTC is running UTC or some other time.
>
> Ignoring drift, a RTC running UTC never changes, so the hardware
> always knows the correct time. The Local Time displayed is just a
> matter of sensible configuration.
>
> My question, posed above, is *only* of concern where the RTC is
> running non-UTC, ie it gets fiddled with twice a year. At these two
> times, the RTC could be subject to incorrect alterations by
> erroneously configured OSes, or even multiple OSes perfectly
> configured, but unaware of each other's actions.
>
> > I give it a kick manually, which of course involves entering an
> > admin password...
>
> which is the necessity we're trying to avoid.
>
> ¹ There's another similar concern should you have more than one OS
> thinking it's responsible for measuring and taking account of clock
> drift. Whether this is going to concern people who are rebooting OSes
> all the time is moot.
>
> Cheers,
> David.
>
Reply to: