[ntp:questions] Synchronize distributed PCs with GPS 1 PPS and NTPD for OWD measurements

Joachim Fabini Joachim.Fabini at tuwien.ac.at
Mon Sep 14 11:40:41 UTC 2015

On 14.09.2015 12:43, Hal Murray wrote:

> Joachim Fabini said:
>> - Re-compile your kernel for LinuxPPS support, following the instructions on
>> http://linuxpps.org/wiki/index.php/LinuxPPS_installation .
> That hasn't been necessary for a long long time.

Most recent distributions have PPS line support enabled by default.
Still, kernel build is necessary if you have special driver requirements
or change options -  I recompile measurement kernels for increasing the
Hz rate. The page contains some outdated information but some of it is
valuable (in particular the reference to the ppstools repository and
timepps.h copy that is essential for building ntp).

> What version of the kernel are you using?

3.8 - 3.13

> Recent kernels need something like:
>   ldattach 18 /dev/ttyS0
> which creates /dev/pps0

Yes, that's what I do. Ideally you can automate it and trigger some
additional ntp prerequisites (udev-related) as recommended on the ntp
pps support page (http://linuxpps.org/wiki/index.php/LinuxPPS_NTPD_support)

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