From owner-freebsd-hackers  Wed Dec 24 10:32:19 1997
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To: Robert Eckardt <roberte@MEP.Ruhr-Uni-Bochum.de>
cc: imp@village.org (Warner Losh), hackers@FreeBSD.ORG
Subject: Re: procedure to adjust clock drift? 
In-reply-to: Your message of "Wed, 24 Dec 1997 18:16:54 +0100."
             <199712241716.SAA17076@ghost.mep.ruhr-uni-bochum.de> 
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Date: Wed, 24 Dec 1997 10:26:56 -0800
From: Amancio Hasty <hasty@rah.star-gate.com>
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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).)

I was told that PCs clocks are usually reliable and they are usually
off by a fixed clock offset so yes I am thinking about adjusting
the frequency on the clock in my PC. Typically, I use ASUS motherboards
which come equip with a Dallas Semiconductor RTC which is supposed
to be good. Guess, I have to go to the Dallas Semiconductor web site
to find out more about my RTC part.


> 
> 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).

Oh, that sounds great most time clocks run about $1000 or so around
here . I wonder if there is a US counterpart.


> 
> 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.
> 

	Tnks
	Amancio