Re: Clarifications about PPS SHM content

[Martin Boissonneault]

Hi Gary,

Thanks for confirming my intuition. This thought came from watching 
ntpshmmon. The answer caused the question ;-)

Follow-up question: I recall someone said that all time sources have an 
influence over the stability of the NTPd time, and if you had one 
unstable time source connected (like the GNSS serial shm?), the whole 
stability was affected even if you have a better, more precise clock 
selected. Considering my GNSS serial SHM has been (x) and is stratum 11, 
do you think it is negatively affecting my stability and should be 
commented out?

I know my ntpviz graphs would look better without the serial shm ;-)

Thanks for your time,
Martin

On 2020-03-19 13:28, Gary E. Miller wrote:
> Yo Martin!
>
> On Thu, 19 Mar 2020 13:24:53 -0400
> Martin Boissonneault <address@hidden> wrote:
>
> > I'm curious as to why NTPd would need to have both the GNSS PPS shm
> > and the GNSS serial shm refclocks in the ntp.conf.
> It does not.  Mostly a hold over from existing practice in the ntpd
> pps driver.  gpsd users do it so they get some time when PPS is dead.
>
> > Wouldn't the PPS
> > shm contain enough time information as collated from GPSd?
> Yes.  ntpshmmon shows this.
>
> RGDS
> GARY
> ---------------------------------------------------------------------------
> Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
>         address@hidden  Tel:+1 541 382 8588
>
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