On Tue, 31 Jul 2001, Bill Studenmund wrote:
> Also, say there are times when ntpd NEEDS to set the date back
> (like say there's a network outage, and the clock has drifted
> forward & needs to be scooted back). Preventing ntpd from moving
> the clock back can, in such a case, make it unable to do its job.
> So systems which need the clock set right will fail.

I *never* want ntpd to make time appear to jump backwards.  I want the
system clock's idea of the time to be monotonically increasing (at a
rate not too far removed from 1 clock second per real second), except
for a possible discontinuity when ntpdate (or something similar) is
run at boot time, or when the sysadmin deliberately does something
unusual.

If ntpd thinks it wants to jump time backwards or forwards by a small
amount, I want it to rather make the clock run slower or faster until
real time and clock time are in sync again.  If it thinks it wants to
jump time backwards or forwards by a large amount, I want it to rather
give up and scream for help.  Depending on the system, I'd probably
put the boundary between a small and a large change somewhere between
5 seconds and 5 minutes.

--apb (Alan Barrett)