Date: Wed, 24 Dec 1997 10:26:56 -0800 From: Amancio Hasty <hasty@rah.star-gate.com> 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? Message-ID: <199712241826.KAA01767@rah.star-gate.com> In-Reply-To: Your message of "Wed, 24 Dec 1997 18:16:54 %2B0100." <199712241716.SAA17076@ghost.mep.ruhr-uni-bochum.de>
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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
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