[ntp:questions] Tidbit for Soekris 4501 NTP users

John Ackermann N8UR jra at febo.com
Sun Aug 19 18:15:09 UTC 2012

This is probably something that very, very few other people are going to 
encounter, but thought I would note it here for posterity.

I'm using the Soekris 4501 with high-resolution Elan CPU for nanosecond 
timestamps as documented at http://www.febo.com/pages/soekris.  When 
using a PPS-only refclock (e.g., pulse from a cesium clock with no 
serial timecode), I found that the PPS signal was not being seen unless 
some other process held the serial port open.

In the non-time-nuts (or even semi-time-nuts) world, you'd never see 
this because the PPS is always associated with a GPS or other device 
that is sending a serial timecode.  But with a PPS-only setup (where the 
prefer peer is a remote host), the symptom is that the PPS source is 
never seen.

The simple cure is to do "cat /dev/pps0 > /dev/null &" as part of the 
startup script.  There's probably a more elegant way, though.


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