[ntp:questions] best gps receiver for time synchronization

David J Taylor david-taylor at blueyonder.not-this-part.nor-this.co.uk.invalid
Wed May 13 17:40:53 UTC 2009

Unruh wrote:
> Since the same machine can run Linux or BSD whose resolution is usec
> or
> nsec, yes, the hardware can do better. The question is how good is the
> software in the kernel. If I do a timestamp on an event, how accurate
> is
> that timestamp?
> Is it msec? Is it 15msec?

The precision with which a standard Windows system call returns the 
current time will be 1 millisecond.  The value reported by that call may 
step in 1, 10 or 15ms steps depending on the version of Windows you use, 
and whether you turn on the "fast" timer (the multi-media timer).

I am running ntp on windows and it is reporting offsets of a fraction of a 
millisecond, so does that mean that the milliseconds reported are within a 
millisecond of UTC?

It's not a matter of "how good" is the kernel, it's what the design 
specifications are, if I understand it correctly, and the design specs for 
different versions of Windows are different.


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