[ntp:questions] NTP Performance on WINNT
David Woolley
david at ex.djwhome.demon.co.uk.invalid
Mon Jul 27 06:47:55 UTC 2009
Steve Kostecke wrote:
>> I'm just not so sure if I can absolutely count on ntpq to determine
>> time offset of NTP synced machines...
>
> ntpq does not calculate anything. It merely displays information
> returned from the ntpd it is querying.
>
I believe that he means the combination of ntpq and and ntpd. The basic
problem is that you are trying to mesure a parameter on a system where
that parameter affects the accuracy of the measurement.
There is also a problem that many other people believe that software
clock time + offset = UTC time (possibly minus). However, when ntpd is
operating in the environment in which Dave Mills expects it to operate,
|UTC - software clock time| << |offset|.
I believe that the parameter the OP actually wants to measure is |UTC -
software clock time|. As this is Windows, and Windows doesn't
interpolate, one would guess that he wants this value at the point of
the clock tick.
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