>As to why the two references that we have seem to be different at >times, I believe this is most likely due to our third party software or >possibly the fact that we have "enable pll" in our NTP configuration >file. From what I've been told by a co-worker, NTP can not read time >off of a serial line with AIX version 3.4 and that we would need to >upgrade to version 4 or 5. This is why we have a third party >application reading time off of the serial line and then disciplining >the local clock on the NTP servers instead of having NTP do all of this >for us. If anyone knows this to be false, please let me know.
I don't know anything about AIX. Most GPS clocks send a message over a serial port and also flap a signal once per second: PPS, Pulse Per Second. One edge of that pulse is on the second boundary. The serial port isn't very good for timekeeping because of the jitter. It will probably get you within a few milliseconds. Most kernels include serial port support that works with ntpd. Using the PPS signal requires special support from the kernel. The usual way is to connect it to one of the modem control signals on the serial port. PPS support is included with the normal kernel sources on FreeBSD. You probably have to turn it on in your kernel building config file. Linux requires a patch which is readily available. If accuracy of a few ms is good enough, you may not need the PPS support in your kernel. -- The suespammers.org mail server is located in California. So are all my other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited commercial e-mail to my suespammers.org address or any of my other addresses. These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
