[ntp:questions] NTP offset doesn't change.

Harlan Stenn stenn at ntp.org
Wed Feb 11 09:53:03 UTC 2015


William Unruh writes:
> On 2015-02-11, Harlan Stenn <stenn at ntp.org> wrote:
> > It's one thing if a system rarely steps.  It's a bit different if those
> > steps happen more frequently.
> 
> Yes. And it is either equally rare that the system will go over 500PPM,
> but sometimes a computer can have a large "natural" drift, (even over
> 500PPM) and that will drastically reduce the "headroom" to deal with
> unusual situations. (ie, if the computers normal drift is 400PPM, that
> means that the effective cap is only 100PPM, not 500). 
> stepping is much worse than high PPM since it is infinite PPM. 

Where would you get the idea that a 400ppm swing would be "normal"?
Or even 200PPM?

> Note that were ntpd designed for 5000 PPM then anything else could
> follow it since it could also do 5000 PPM. 

Sure, and if it was designed for 10S/S it would handle 10S/S swings.  But
none of this has been shown to be normal or useful.

> Yes, we are talking about choices. And all I was saying was that this
> particular choice was somewhat arbitrary. 

That depends on your definition of "somewhat".

More or less, "everything tastes like chicken".  More or less...

H


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