On Fri, Dec 5, 2014 at 9:37 AM, Charles Swiger <cswi...@mac.com> wrote:
> I also make sure that my > timeservers are running in temperature-controlled environments so that > such daily drifts you mention are minimized. I'm starting to think that people answering questions are unsure of the real question so they make a number of assumptions. If you care about sub-millisecond time then you need to say that and the question should be answered in that context. I suspect most of the questions here refer to sub-second accuracy and most of the elaboration is unneeded. If all your external clocks fail I suspect the typical user can depend on the disciplined virtual clock for days. For almost all of human history, the sun or the "fixed celestial heavens" > have provided the most accurate time reference available. Even today, > we add (or subtract, in theory) leap seconds in order to keep UTC and UT1 > aligned to better than a second courtesy of IERS. > > Yes, the USNO, CERN, and so forth now do have sufficiently high quality > atomic clocks which have better timekeeping precision than celestial > observations. > I think there's some confusion here. Search for BIPM paper clock or read < http://www.ggos-portal.org/lang_en/GGOS-Portal/EN/Topics/Services/BIPM/BIPM.html > > Such a point is orthogonal to the notion of how to measure a local clock > I think this is an interesting question. How does one get high resolution measurements of the error in the virtual clock maintained with NTP (or Chrony)? I thought it was done with purpose built systems. I don't expect a random version of Linux on generic hardware to be able to maintain the clock at nanosecond scale. _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
