> Not if that old legacy system isn't an architecture that ntpd has been > ported to.
That is exactly the case. The old legacy system cannot be modifed. There are discussions on upgrading the old system to use NTP, but we can't hold our breath on that. I did not mention this in my previous post, the systems do NOT have to synched to a standard time zone or "real time" say UTC/GMT. The systems I am trying to link together just need accurate time synchronization to each other only, beginning from when the systems start up. > Use a daemon that listens to the UDP clock pulses and, after suitable > preprocessing, sends them to ntpd via the SHM driver. That is the approach I had in mind. What worries me is the "suitble preprocessing" part as well as figuring out the exact parameters to pass to the ntpd via the SHM driver. Does the SHM require a 1HZ PPS or is my ~0.1HZ pulse OK to use? > The stability of the time base is of primary importance. I imagine it is quite stable. The old legacy system is a very large scale miltary system used for high-precesion data loading of weapon data. I am in a prototype/feasiblity mode right now and it is difficult (i.e. very time consuming) to obtain the documentation for the old legacy system that has the specs on the interface. I am hoping David Mills is reading this post because (according to his web site) he has a current contract working on the same system I am trying to link to! I really would like to synch my internal network to a external clock reference (say an Internet site or GPS unit) that is very stable so I can measure just how stable/precise/accurate the old legacy system is. Unfortunaley, that is not possible in the lab environment I am working in. So, since the single board computer I am using for the ntpd server has a cheap clock in it that I know drifts in a big way, I am unsure how to measure the accuracy of the old legacy system. The only tool I have right now is an 8 channel digital oscillocope that I trigger with general purpose output pins. Some of the nodes on my system trigger those pins at absolute times and I can measure the jitter between them and the master ntpd node. I am seeing no more than +/- 1 ms jitter between the slave nodes and master node. > Actually, it sends a packet containing the clock counter (ostensibly > milliseconds since system startup) approximately every ten seconds. > > That's not the same thing as "just tick[ing] periodically". That is correct. _______________________________________________ questions mailing list questions@lists.ntp.isc.org https://lists.ntp.isc.org/mailman/listinfo/questions
