[ntp:questions] 500ppm - is it too small?

Ulrich Windl Ulrich.Windl at RZ.Uni-Regensburg.DE
Thu Nov 12 12:25:05 UTC 2009


"David J Taylor"
<david-taylor at blueyonder.not-this-part.nor-this.co.uk.invalid> writes:

[...]
> I think this is an excellent point.  It would be fascinating to see a
> histogram of computer clock frequency error, so that one could make a
> statement like "500ppm satisfies 98% of computer clocks" with some degree of
> authority.  I'm not aware of any such data, though.

Actually I have such data for every NTP server here. One Sun/Solaris
machine has a frequency wander of over 400 PPM (~ -130..+130 PPM) while
the other machines are limited to a few PPM. And the absolute error is
less than 50 PPM.

>
> Cheers,
> David 




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