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Date: Thu, 12 Sep 1996 05:41:46 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199609111941.FAA09143@godzilla.zeta.org.au>
To: hackers@freebsd.org, hasty@rah.star-gate.com
Subject: Re: clock drift and clock.c
Sender: owner-hackers@freebsd.org
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>Assuming that xntpd gives over a 24 hour period a clock drift of 122,
>what are the mods to clock.c to eliminate the clock drift. In my
>case, I think that my clock drift is fix.

In -current you can adjust the clock frequency using
`sysctl machdep.i8254_freq=whatever'.  In all versions you can do the
same using `options TIMER_FREQ=whatever' in the kernel config file.
However, this is only good for adjusting to the nearest 50 ppm.  I
will commit some changes to make this work better RSN.

I guess it's easier to just use xntpd without any network connections
or clocks.  Put `122.000 1' or `-122.000 1' in /etc/ntp.drift, start
xntpd, then kill xntpd (no point in keeping it running since it won't
do anything other than initialization).  The `1' in ntp.drift is a
flag that tells xntpd to use the kernel PLL.  It will start the kernel
PLL and won't stop it when it is killed.

Bruce