[Vm-dev] [Cog] Funny thing about time

[Eliot Miranda]

So what's the algorithm?  If the time changes by more than half an hour
(between the heartbeat sampling the clock) it's a clock change but if its
less than half an hour its clock drift.  What threshold value would you use?
 10 minutes? Half an hour?  A minute? I'm interested in opinions here This
is easy to add and a good idea, but getting that magic constant right is
important.

On Wed, Jan 12, 2011 at 4:24 AM, Igor Stasenko <siguctua at gmail.com> wrote:

>
> Well, putting the CMOS stuff aside,
> i really don't like that VM could hang indefinitely if user will
> adjust the clock settings.
>
> On 12 January 2011 13:22, Levente Uzonyi <leves at elte.hu> wrote:
> >
> > On Wed, 12 Jan 2011, Frank Shearar wrote:
> >
> >>
> >> Yes, Windows like to set the CMOS clock to local time, and Linux likes
> to
> >> use UTC.
> >>
> >> My brother recently ran into a similar problem with a FreeBSD machine
> >> running as a guest inside a Windows host. He had to touch
> >> /etc/wall_cmos_clock to fix it.
> >>
> >> From the adjkerntz man page:
> >>
> >> If the file /etc/wall_cmos_clock exists, it means that CMOS clock keeps
> >> local time (MS-DOS and MS-Windows compatible mode).  If that file does
> not
> >> exist, it means that the CMOS clock keeps UTC time.
> >>
> >> Maybe there's a similar Linux/Mac fix?
> >
> > Yes, there is, but different linux distributions have different files
> IIRC.
> > Btw, if you tell linux to assume that the hardware clock stores the local
> > time, you'll still have problems after daylight saving related time
> changes,
> > because both OSs will adjust the clock.
> >
> >
> > Levente
> >
> >>
> >> frank
> >>
> >> On 2011/01/12 01:18, Chris Muller wrote:
> >>>
> >>> Every time I jump back and forth from Windows to Linux on my primary
> >>> laptop, the clock is wrong...
> >>>
> >>> On Tue, Jan 11, 2011 at 4:37 PM, Igor Stasenko<siguctua at gmail.com>
> >>>  wrote:
> >>>>
> >>>> Yesterday on my comp two separate running images are hung
> >>>> simultaneously, while i were doing something completely outside of
> >>>> them.
> >>>>
> >>>> And now during reading  the sqUnixHeartBeat.c:
> >>>>
> >>>>
> >>>>        /* The native clock may go backwards, e.g. due to NTP
> >>>> adjustments, although
> >>>>         * why it can't avoid small backward steps itself, I don't
> know.
> >>>> Simply
> >>>>         * ignore backward steps and wait until the clock catches up
> >>>> again.  Of
> >>>>         * course this will cause problems if the clock is manually
> >>>> adjusted.  To
> >>>>         * which the doctor says, "don't do that".
> >>>>         */
> >>>>
> >>>> i start recalling that yesterday i adjusted clock back by 1 hour,
> >>>> because after installing a windoze in dual boot it was set it wrongly.
> >>>>
> >>>> But of course it could be anything else :)
> >>>>
> >>>> --
> >>>> Best regards,
> >>>> Igor Stasenko AKA sig.
> >>>>
> >>>
> >>>
> >>
> >>
> >
>
>
>
> --
> Best regards,
> Igor Stasenko AKA sig.
>
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