On Tue, 2005-08-09 at 14:51 -0400, David Gilbert wrote: > But ... since there are long patches of time where I'm not mobile, I > was wondering if anyone had looked at using a Bluetooth GPS for > timekeeping. Has anyone also ever had an ntp server sometimes use a > GPS and othertimes use other servers ... depending on the availability > of the GPS?
The former would depend strongly on the characteristics of the Bluetooth protocols, at least when it comes to accuracy. Keeping time to the half-second or so would be pretty easy, I would guess. The latter is the way it already works. Just configure other peers in your ntp.conf along with your GPS, viz: pps /dev/pps0 assert hardpps server 127.127.41.0 prefer # GPSClock fudge 127.127.41.0 stratum 0 fudge 127.127.41.0 time1 -1.0 peer 127.127.22.0 # PPS refclock fudge 127.127.22.0 stratum 0 flag3 1 # name it as a good clock peer 128.9.176.30 # timekeeper.isi.edu peer 164.67.62.194 # tick.ucla.edu peer 63.149.208.50 # nist1.datum.com peer 192.43.244.18 # time.nist.gov peer 206.223.0.15 # tick.exit.com That's the configuration for tock.exit.com. It uses the GPSClock if it's available, otherwise it falls back to the best of the other tickers. -- Frank Mayhar [EMAIL PROTECTED] http://www.exit.com/ Exit Consulting http://www.gpsclock.com/ http://www.exit.com/blog/frank/ _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
