ruck@sphere.UUCP (John R Ruckstuhl Jr) (07/03/90)
The /usr/lib/crontab supplied with my 3b1 software has the following
entry:
3 3 * * 0 /bin/su root % /etc/clockupd.wk > /dev/null
/etc/clockupd.wk is a simple shell script:
#sccs "@(#)fndetc:clockupd.wk 1.7"
# Write to the hardware clock every Sunday morning to accomodate
# synchronization of time between s/w and h/w clock in case day light
# saving time is being used. Wait a minute to prevent recursion.
# Note: backslash needed to avoid SCCS conflict
sleep 60
date `date +%m%d%H\%M`
Why do we need to synchronize the clocks? What looks directly at the
h/w clock rather than the s/w clock (besides the initialization of the
s/w clock at boot-time.
And, if this truly synchronizes the clocks, why have they apparently
diverged so much withing 26 hours -- I run Vernon Hoxie's routine Monday
mornings to set my clock, and a typical log-file entry is:
Mon Jun 18 05:21:51 1990, Sys. Corr: -37 sec. RTC Corr: -6 sec. 50 dst
Showing (*I think*) a divergence of 31 seconds between the clocks
accrued during the 26 hours since the Sunday 3:30am synchronization.
But if the clocks were that inaccurate, I'd expect larger than 37s or 6s
absolute correction would be necessary after a full week (since the
previous Monday's correction).
Regards,
John.
--
John R Ruckstuhl, Jr sphere!ruck, ruck%sphere@hp-col.col.hp.com