On 2015-02-11, Harlan Stenn <st...@ntp.org> wrote: > William Unruh writes: >> On 2015-02-11, Harlan Stenn <st...@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?
I did NOT say a 400PPM swing. I said a static 400PPM drift. That would then only allow a 100PPM headroom for dynamic drifts. Or if one had a 498PPM static drift, one would be left with a 2PPM headroom. > >> 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. Most drifts are static drifts, not swings. ntpd does not differentiate. > >> 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 _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions