A possible woody solution for the RTC (Re: Scary bugs)
On Mon, 31 Jan 2000, Martijn van Oosterhout wrote:
> I run a simple NTP server locally and the CMOS does still drift.
Strange. Did you enable "Advanced RTC support" for the kernel? I'm not sure
it's need, but I have it enabled and other than a 30-minutes window
weirdness in the 11 minute mode, the kernel is keeping it in sync with
system time. I don't know if the advanced RTC support is the default in
Debian kernels, check for CONFIG_RTC in /boot/config-2.2.*
> Gosh. Have you evver installed adjtimex? Have you looked at the --log
> command?
Not really.
> Here is an example of an adjtimex --log being run out of cron. Then
> adjtimex -r produces:
>
> hecate root/~>adjtimex -r |tail -5
> least-squares solution:
> cmos_error = -8.41455 +- 0.00008 ppm suggested adjustment =
> 0.7270 sec/day
> sys_error = -13.07469 +- 0.00007 ppm suggested tick = 10000
> freq = 856863
So it adjusts (or at least measures) both the RTC and kernel clocks? Hmm,
that's interesting... Let me fetch the source and read it...
Ok, done and glad I read it. So adjtimex is actually capable of doing all
the training we need. It can do it through ntp/ntpdate and through human
interaction.
One could simply create the drift file (/etc/adjtime) always using
adjtimex/ntp/chrony (and a script) and patch hwclock never to write to that
file. Easy and clean, I like it :-) You might just have solved part of the
problem for woody, I think.
Of course, all this 'clock training' work is probably already done right
(see chrony package). Maybe patches to hwclock for robusteness (always a
good idea), and giving up a clock-drifting-corrected default debian install
would be better.
IMHO proper documentation teaching the user how to fix the drift using
adjtimex and a patched hwclock which could go in the DDP page (the System
Administration Manual is a good place, I think) would be enough.
--
"One disk to rule them all, One disk to find them. One disk to bring
them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh
Reply to: