Martin Burnicki wrote: [] > I think the 10/15 ms switching is just used to maintain a kind of > synchronization between the standard tick rate and the MM timer tick > rate. > > Martin
Martin, Thanks for that detailed explanation, which I've saved for future reference. What is still unexplained on this system, though, is why on Friday at 14:30 the system change from (I suspect) a single stable clock timing (one unaffected by running MM applications) to a 10/15ms timing which affects NTP like crazy? Looking now, the system is as stable with the MM timer running at 1KHz as it ever was before. I'm going to see what your NTP Time Server Monitor says, as I've got the statistics from before the problem. (Thanks for the excellent tool, by the way). Pre-fault Nov 29: frequency -7.6 .. -7.5, offset -0.006 .. +0.006 During the fault: Dec 04: frequency -68..-63, offset -0.6 .. +0.6 Today: Dec 08: frequency -16.2 .. -7.56, offset -0.06..+0.06 (but still stabilising) So I am coming back towards the drift value I had before the fault, and the stability is similar (the 0.06 looks like a single transient when I tried stopping and restarting QuickTime to check my own measurement program). OK, I'm now revising my view of what happened. My best guess now is that before the fault occurred, I was running with the MM timer permanently enabled, and that's what made the system stable. Something caused that to stop. What? Does XP SP2 permanently run the MM timer at 1KHz? News to me if it does! Too much thinking out loud! Cheers, David _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
