[ntp:questions] Driver Help?
karl at denninger.net
Tue Jun 12 23:59:05 UTC 2007
Richard B. Gilbert wrote:
> Karl Denninger wrote:
>> I'm hacking a copy of the NMEA driver to work with the CDMA modems
>> (which provide a clock signal even if not subscribed - kinda
>> interesting) and have it talking to the device.
>> But - even though the dispersion looks reasonable and so does jitter,
>> the application refuses to consider it "synced".
>> I have the following.....
>> ntpdc> sysi
>> system peer: CDMA(0)
>> system peer mode: client
>> leap indicator: 11
>> stratum: 16
>> precision: -19
>> root distance: 0.00000 s
>> root dispersion: 0.00165 s
>> reference ID: [184.108.40.206]
>> reference time: 00000000.00000000 Thu, Feb 7 2036 0:28:16.000
>> system flags: auth monitor ntp kernel stats
>> jitter: 0.001129 s
>> stability: 0.000 ppm
>> broadcastdelay: 0.003998 s
>> authdelay: 0.000000 s
>> ntpdc> peer
>> remote local st poll reach delay offset disp
>> *CDMA(0) 127.0.0.1 0 16 377 0.00000 0.241065 0.00697
>> Obviously, I'm missing SOMETHING....... the dispersion looks
>> reasonable, but it will not lock up on the clock. Any idea where I
> I think you may be missing the "*" in column one above. That indicates
> that ntpd has your CDMA(0) clock as the synchronization source.
> The offset looks a little high unless ntdp was started quite recently.
> Bear in mind that ntpd needs time to beat your clock into submission.
> Thirty minutes is a good length of time to wait before taking offset and
> dispersion figures seriously.
Ok... I'll wait a good long while (several hours)
This thing isn't the BEST time source ever invented, but I've got a few
folks who would like it as a solution, and of course I'll contribute the
driver back to the codebase - if I can get it to work!
The other problem - that the driver's "start" routine is never called
unless ntpd is not running as a daemon - is puzzling. Not quite sure
why that would happen.... but the routine is definitely not being
entered, although the base code IS running (the startup message gets
logged to the syslog and there are no errors.)
Its almost like the config file switch is ignored if its not in debug
mode and thus didn't attempt to start the clock. I can get a sysi but a
peer shows no data (as expected with no clocks or peers attached)
I built this from source of the current RC2 source - I'm a long-time
NTPD user (and have a Stratum 1 server running here with a GPS+PPS
source), but haven't (yet) attempted to integrate a "new" clock into the
Karl Denninger (karl at denninger.net)
More information about the questions