In article <[EMAIL PROTECTED]>, [EMAIL PROTECTED] wrote: > I know that sometimes, it's boring to anwser to simple questions but
It's not a simple question, at least not without a lot of detail about your particular case that I doubt you are allowed to tell us, and even that would only make the answer simple. > one more time, you don't answer to my question... juste make a sentence > please for explaining. Estimated error is the estimated error compared > to the server time, or compared to the reference clock? For me, it's It is not the instantaneous error, but rather a statistical error bound to some level of confidence; on most occasions, UTC will be somewhere between local clock time - estimated error and local clock time + estimated error, but on other occasions it will be outside that range. If ntpd knew the instantaneous error, it would corect it so as always to be zero! It is intended to be relative to true UTC, not to the local time on any particular piece of hardware, although, unless the reference clock is giving out good error estimates itself, it might be rather closer to being referred to the reference clock. You shoulnd't, of course, have a network that derives its time from a single reference clock. >From the sounds of things, I think you should be telling your manager the maximum error, as this one makes all the worst case assumptions, except for lost clock interrupts and the application program time reading precision, and is pretty close to the 100 percentile confidence limit. If his system is using any Windows machines, make sure that you tell him that Windows application programs can only read the time to a precision of 10ms or worse. Also point out to him that time is generally only useful in conjunction with external events, and all systems have an indeterminacy in the delay between the external event and when the time is read, that, without special hardware, and operating systems, is often several milliseconds. If you need to be concerned about 2ms error estimates, you, almost certainly, need to be doing a white box analysis of the timing latencies of the system and should be asking much more specific and technical questions. If you want us to tell you whether or not the timing is good enough for you, you need to tell us the nature of the problem the computer system is trying to solve. _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
