Seting the hardware clock

stan stanb at
Tue Jul 15 06:33:33 PDT 2003

On Tue, Jul 15, 2003 at 08:32:23AM -0400, Lowell Gilbert wrote:
> stan <stanb at> writes:
> > ;m struggling with getting the hardware clock (BIOS clock) equal to the
> > kernels time.
> > 
> > On my Linux boxes a utility called hwclock is run on the way down to
> > synchronize the 2.
> > 
> > The problem I'm running into is that if the time on the system gets to far
> > out of date for ntpd to bring it into synch, then I can update the kernels
> > clock with ntpdate. But when I reboot the old incorrect time comes back.
> > 
> > I ran into this during some software testing, that required setting the
> > clock pretty far off of real time, and it was a PIA to get the machine back
> > to the correct time.
> > 
> > How _should_ this be handled?
> Most people run ntpdate before starting ntpd.
> The rc.conf enable flags for the two programs support this.

OK, that's exactly what I _am_ doing. So here is teh scenario that creates
the problme.

1. Set the hardware clock to some truly strange time (for testing

2. Reboot.

   a. time is set by the BIOS to the wrong time
   b. ntpdate corrects this (for the kernel).
   c. ntp keeps the time acurate (for this run session).

3. shutdown (BIOS time is not corrected).

See the problem?

"They that would give up essential liberty for temporary safety deserve
neither liberty nor safety."
						-- Benjamin Franklin

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