[ntp:questions] Second attempt at GPS-18 based NTP server
agcarver+ntp at acarver.net
Thu Feb 2 21:06:09 UTC 2012
On 2/2/2012 02:02, Paul Duncan wrote:
> Please note, I have not done any recompiling of the kernel at this stage
> - just using the GENERIC kernel, because after reading the comments from
> Per Hederland in the System software customisation section of the above
> web page, it seemed unnecessary. Comments?
Sent the first email accidentally before I finished.
The generic BSD kernel does not enable PPS support by default. You must
recompile to enable PPS.
The page you quoted says the following the section "System software
customization" (about 45% down the page in the Software section):
System software customisation
Need to add one line to the Kernel configuration:
and recompile the Kernel. On my 133MHz/48MB system this can take
several hours. Note the configuration suggestions below before you
recompile the kernel.
It does appear that your system sees PPS though it hasn't synced to it
yet (there's no indicator in the first column). However, I haven't been
able to use PPS unless I enable PPS in the kernel. Try it in the
current configuration and see how it works. Then if you feel like it
try again with PPS_SYNC enabled and see what happens.
I'm using NetBSD (though on sparc hardware not x86 so serial ports
behave a bit differently) and I do have PPS_SYNC enabled in the kernel.
I am bringing in PPS to ntpd via the PPS refclock because the GPS is
using SiRF binary not NMEA.
> remote refid st t when poll reach delay offset jitter
> o127.127.22.0 .PPS. 0 l 13 16 377 0.000 0.004 0.061
> 127.127.28.0 .GPSD. 0 l 81 128 377 0.000 -32.127 6.525
> +188.8.131.52 184.108.40.206 2 u 4 512 377 40.196 0.655 0.247
> +220.127.116.11 18.104.22.168 2 u 16 512 377 57.519 -0.108 0.377
> +22.214.171.124 126.96.36.199 2 u 389 512 377 93.350 -0.281 1.096
> *188.8.131.52 184.108.40.206 2 u 140 512 377 94.450 -5.508 0.301
> +220.127.116.11 18.104.22.168 2 u 220 512 377 87.476 3.088 2.851
(I hope mine stays running for longer than five days, I'm on day two
after a restart of ntpd.)
More information about the questions