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From: Robert Eckardt <roberte@MEP.Ruhr-Uni-Bochum.de>
Message-Id: <199712241716.SAA17076@ghost.mep.ruhr-uni-bochum.de>
Subject: Re: procedure to adjust clock drift?
In-Reply-To: <199712232054.NAA24318@harmony.village.org> from Warner Losh at "Dec 23, 97 01:54:25 pm"
To: imp@village.org (Warner Losh)
Date: Wed, 24 Dec 1997 18:16:54 +0100 (MEZ)
Cc: hasty@rah.star-gate.com, hackers@FreeBSD.ORG
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It was Warner Losh who wrote:
> In message <199712231738.JAA01502@rah.star-gate.com> Amancio Hasty writes:
> : Does anyone have a procedure to adjust the clock drift in a PC?

If you think of hardware tuning the frequency:  No, I don't know.
(It will depend e.g. on whether you have the machine running all
 the time or just during the day (temperature).)


If you are happy with periodically synchronizing the clock to
some time standard:

I wrote some time ago a driver which connects a cheap DCF clock
(german radio standard time signal (others should be easy to implement)
controlled, price at about 10-20 $) via a simple interface to my
(otherwise unused :-) game port (iX 11/1994p6).

The kernel polls every 1/100 s the state and buffers it for a
user program to evaluate (which I run via cron twice a day).
In a network I use xntpd with the machine with the clock configured
as a stratum 1.

The driver (including a plan for the interface) can be found at:
   ftp://hadron.tp2.ruhr-uni-bochum.de/pub/DCF/DCF77-1.3-beta.tar.gz

(the `beta' reflects the fact that the Readme is in German and it
 needs some hand work to apply the patches to the kernel (no port))

A slightly different solution exists for the serial port with direct
interface to ntp (in iX 10/1994p154).
In this article the authors point to parse/util/dcfd.c in the
NTP-distribution.


Robert

> 
> ntp?
> 
> It is already in the tree as xntpd and friends...
> 
> Warner
> 


-- 
Robert Eckardt                \\ FreeBSD -- solutions for a large universe.(tm)
RobertE@MEP.Ruhr-Uni-Bochum.de \\       What do you want to boot tomorrow ?(tm)
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