Hi all, I have two NTP-related questions: 1. We are setting up a White-Rabbit[1] network for time-distribution. We 'seed' the WR-network with 10MHz and PPS signals form atomic clocks. This means on each computer in the network there's a very accurate PTP-server running on the WR-card, as well as the normal system time on the computer. For fun I logged both the system-time (kept on time using NTP) as well as the PTP time and plotted the error: http://www.anderswallin.net/wp-content/uploads/2013/07/NTP_time_2013jul26.png I was wondering if this plot is typical for a (good?) NTP-disciplined computer clock? Without NTP the free-running clock shows >40 ppm error: http://www.anderswallin.net/wp-content/uploads/2013/07/freerunning_vs_ntp_2013jul26.png
The -16ms offset in this graph is probably due to my naive program where we first call a simple function that asks the NTP time, and then over a serial link ask for the PTP time. In reality the two time-stamps might be better synchronized - I don't know. The slow variation I see should be real however and completely due to drift in the NTP time, since the WR-time is much more accurate. 2. Is it possible to run several NTP-clients on one machine? That means I'd have multiple "system-times" each synchronized to its own NTP server. If this is possible I'd like to monitor several NTP-servers at once and log their time-stamps against our WR-time which is known to be good. thanks, Anders [1] http://en.wikipedia.org/wiki/The_White_Rabbit_Project _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
