[ntp:questions] Stick to PPS, even if the prefer server fails

alkopedia at googlemail.com alkopedia at googlemail.com
Thu Mar 26 13:20:07 UTC 2009

On Mar 26, 5:46 am, Unruh <unruh-s... at physics.ubc.ca> wrote:
> So, I have PPS running the shm refclock, with the seconds supplied by the
> local clock (ie the reading from the system clock) and the usec from the
> PPS signal.  Since I do not expect the local clock to suddenly shift by a
> second, its usec discipline should be fine. I mark it as the preferred
> server. (The PPS shm is run only once the local clock is disciplined to
> within .1 sec by the other sources).

This could be a good idea in my opinion, but someone with better
knowledge should comment that.
I'm trying this right now. As soon as the GPS/DCF gets dark, the LOCAL
clock is used as prefer peer and PPS is still used to sync. Only thing
that comes to my mind are leap seconds: As the RTC is only synced by
the kernel every 11 minutes, it could cause troubles when the LOCAL
clock suddenly is 1 s off GPS/DCF. But I guess it will be marked as
false ticker until the next kernelsync.

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