Re: How to use /etc/adjtime

[John Hasler <john@sugarbit.com>]

David writes:
> It's not clear to me which NTP (protocol) packages are set up to use
> the util-linux stuff, assuming you're not rolling your own
> startup/shutdown scripts. (That's the problem in the Subject line, in
> a sense.)

Chrony can.  I don't know about Ntpsec.  But that doesn't get the
adjustment made early enough.

> The critical part of the whole operation AIUI is not what happens at
> startup,

The tricky part, I think, is correcting the rtc before it is used to
initialize the system time.  Otherwise you'll still have to step or slew
the system time.

> but at shutdown: writing to the RTC, and the correct preservation of
> its state.

You write to the rtc and to /etc/adjtime periodically at a rate
determined by the computed hot drift rate and also during a controlled
shutdown.
-- 
John Hasler 
john@sugarbit.com
Elmwood, WI USA