On Fri, 08 Sep 2006 07:24:14 PDT, "Garrett D'Amore" wrote:
> Perry E. Metzger wrote:

> > You miss #3
> >
> > 3) As with my laptop, sometimes the box is connected to the network
> >    and has access to external references, and sometimes it is not, and
> >    there is no easy way to predict in advance what state you will be in.
> >   
> 
> In case 3, ntp will correct the drift when you connect.  While
> disconnected, if you did say 10 shutdowns/restarts a day, the worst case
> drift is about 20 seconds.  I know of onboard RTCs that drift that much
> per day anyway.   (Granted, that's pretty darn bad.)
> 

No.  That's the whole point.  If you don't write the clock on each 
shutdown then the drift is zero.  At startup your machine will be anywhere 
within a second of real time (assuming your RTC doesn't drift); but since 
you never write that slightly erroneous value back to the RTC there's no 
systematic change and thus no compounding effect.

R.