"David T. Ashley" <[EMAIL PROTECTED]> writes: > "Richard B. Gilbert" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] >> David T. Ashley wrote: >>> >>> Any insight into whether 24 PPM is excessive for my server? >> >> Consider that a computer manufacturer typically spends something like $2 >> US on the components for the clock! Consider, also, that they provide no >> way to adjust the clock hardware. Computers are designed to compute, not >> to keep time. The original IBM PC and PC/XT did not even have a clock; if >> you wanted a clock it was an add-on at extra cost from a third party. >> >> 24 PPM is pretty good. Anything up to a hundred or two will usually work >> just fine. > > Thanks. Interesting. It seems to be a really steady error, i.e. seems to > always be between 24 PPM and 24.5 PPM.
That is the static frequency offset of your oscillator. > > I think I'll write a little software to plot it at a sampling frequency of > once per hour. I'm wondering if it varies by time of day, temperature, etc. It varies widely with temperature. I once plotted the drift over a few days on an old Sun ss20 I had on my desk, just inside a window, and it was easy to see if it had been a sunny day or not. I also plotted drift vs cpu temperature on an old Sun UE-450, and from the plots I cold deduct how the office air conditioning was programmed, even if the cpu temp only changed by about 1° between day and night and over the weekends. I have tuned a kernel variable in my pc running Solaris nevada so the drift is currently -0.229. I may be able to get it closer to 0, but I'm alright with that value. It was around -35 when I started, and the old motherboard was around -17. ntp does a good job to compensate for this, so only real nerds, like me, bother with this. :-) _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
