clock synchronization

[Longman, Bill]

> What's a good way to set this automatically at boot time rather than
> having to do it every time by hand?  Would it be in the spirit of how
> startup configuration works in YDL to add something like the following
> to /etc/rc.d/rc.sysinit (just before the line that runs hwclock):
> 
> if [ -x /sbin/adjtimex ]; then
>   [ -n "$TICK" ] && ADJTIMEXFLAGS="$ADJTIMEXFLAGS -t $TICK"
>   [ -n "$FREQ" ] && ADJTIMEXFLAGS="$ADJTIMEXFLAGS -f $FREQ"
>   [ -n "$ADJTIMEXFLAGS" ] && /sbin/adjtimex $ADJTIMEXFLAGS
> fi
> 
> and then specify TICK=10003 and FREQ=whatever in /etc/sysconfig/clock?
> Or would that be asking for trouble by breaking other programs'
> assumptions about the contents of the config file?
> 
> If I instead use ntp to synchronize with a time server, does it still
> make sense to set the tick and frequency at startup as a "head start",
> or does ntpd maintain this information between sessions?

Ray, NTPD does a good job of keeping track of the hardware realtime clock.
According to the man page, at least, it provides a mechanism to slew the
clock so that after some learning, it tweaks the kernel similar to what
you've done in the above script.

You may also want to read the man page for "hwclock".

Bill