[ntp:questions] Query about NTP accuracy

David J Taylor david-taylor at blueyonder.not-this-part.nor-this.co.uk.invalid
Fri May 22 13:06:09 UTC 2009


Richard B. Gilbert wrote:
[]
> I'm not sure that ANYTHING, other than a local atomic clock, is going
>  to get you microsecond accuracy.  10 milliseconds is probably
> attainable for other than Windows clients.  The Windows clock ticks
> every 17 milliseconds and may be accurate to within a few hundred
> microseconds but, given the available resolution, you have no way to
> determine if it is that accurate.

Gerneally agreed, although Windows /can/ do within perhaps 3 milliseconds 
with NTP and a stratum-1 server on the same LAN:

  http://www.satsignal.eu/mrtg/bacchus_ntp-b.html

  http://www.satsignal.eu/mrtg/narvik_ntp-b.html

  http://www.satsignal.eu/mrtg/hydra_ntp-b.html

when running continuously, although not when running certain USB devices 
which seem to affect NTP rather badly:

  http://www.satsignal.eu/mrtg/gemini_ntp.html

Cheers,
David 




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