Clock?

[Bernardo Innocenti]

C. Scott Ananian wrote:
> On Dec 23, 2007 4:55 PM, Bernardo Innocenti <bernie at codewiz.org> wrote:
>> Jerry Van Baren wrote:
>>
>>> Hmmm, odd.  After setting the hwclock with --utc, my /etc/adjtime has
>>> "UTC" but, when I cycled power, my system clock was off by my timezone.
>>> Ahh, my /etc/adjtime has "0" instead of "UTC" on the second line.
>> This is probably because adjtime is marked writable in /etc/rwtab,
>> but not preserved in /etc/statetab.  I'll fix that.
> 
> Bernie, be sure to open a trac bug so that we can get this into
> Update.1 if possible.
>
> (Just to clarify, it should be *moved* from /etc/rwtab to
> /etc/statetab, not just added to statetab -- but I'm not 100%
> confident that this is correct.  Please read the man page for hwclock
> carefully.  I think we should really be passing --noadjfile to
> hwclock, and if /etc/sysconfig/clock actually states UTC=true (trac
> #5648) then adjtime should not have the UTC offset in it.)

After some thought, I'm convinced we should *not* preserve
adjtime across reboots.  Preserving adjtime would provide a
minor accuracy improvement, but it's not strictly needed for
correctness, because the --utc flag gets passed both on system
boot and on shutdown.

The reason why we can't effectively preserve adjtime is that
the stateless Linux mounts happen at boot time after hwclock,
so there's no easy way to do it right without ugly surgery in
the rc.sysinit.

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