Hal Murray wrote: > Spoon wrote: > >> In my situation, I don't care what time it is, but my clock needs >> to tick at the correct rate. > > How accurate do you need it? > > You can get "pretty close" if you figure out what the drift > should be and use that. > > You can get that two ways. > > One is to let ntpd run while connected to the outside world. > It will leave the answer in log files and /var/ntp/drift or > wherever.
The problem with that solution is that the frequency offset of the system clock changes by a huge amount every time the system reboots. cf. thread titled "Clock skew changes drastically between reboots" > The other is to do it by hand. Start your system with no ntpd. > Compare it's time with a known good clock. Wait a day/week/whatever. > Compare the clock again. Now compute the drift. Same problem as above. > If you can measure time within 1 second, you will have to wait > ~2 weeks to get within 1 ppm. The drift on some of my boxes is > ~100 ppm, so that would correct most of the error. > > Note that temperature has a significant influence on drift. > Your correction factor may change over the seasons or as > you rearrange things in your machine room. What are the other parameters that influence frequency offset? > You may get the wrong answer if you "connect to the outside > world" by moving the system to another location with a different > temperature. I cannot set the frequency offset once and for all and hope for the best. There has to be some form of synchronization. Regards. _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
