Subject: Re: acpi timer problems?
To: George Michaelson <>
From: Steven M. Bellovin <>
List: current-users
Date: 06/26/2006 00:19:51
On Mon, 26 Jun 2006 13:51:50 +1000, George Michaelson <>

> without having looked at code (always EFATAL) you would hope that a
> zero driftfile was a special case, and did some kind of 'average over
> <n> x initial samples' interpolation to get an initial approximation at
> least close to the right side of the asymptote..
> surely dave mills would have DTRT when initializing from zero, as
> distinct from cached state?
> Ie, if the driftfile is predictably wrong, because you changed
> timesource, I can't see how its ever right to keep it..
I think that that's Dan's point -- /var/db/ntp.drift is for state between
boots.  It's supposed to measure the difference over time between your
machine's clock and reality, and you rarely switch clocks.  It isn't
supposed to compensate for the errors in your ntp peers; ntp assumes that
there's One True Time, and doesn't use averaging, for example.

		--Steven M. Bellovin,