Subject: booting laptops on battery power vs. the clock
To: None <netbsd-users@netbsd.org>
From: Steven M. Bellovin <smb@cs.columbia.edu>
List: netbsd-users
Date: 09/26/2007 18:45:25
I had an incident the other day where my machine couldn't keep time --
despite running ntpd, the clock was running very fast. Restarting ntpd
after running ntpdate and removing /var/db/ntp.drift didn't help. I
finally rebooted.
It occurred to me, though, that the last reboot had been done when
running on battery power. BSD/OS used to have problems like that; it
would get the clock frequency wrong.
I'm running 4.99.31 on a Thinkpad. Sysctl shows
kern.timecounter.hardware = i8254
but that's auto-set. Estd is running. Ntpq shows that the new ntpds
do indeed establish associations with outside time servers. I've seen
a similar symptom on a 4.0rc2 laptop, though I don't have full details
about its past reboot.
Thoughts?
--Steve Bellovin, http://www.cs.columbia.edu/~smb