[ntp:questions] Re: is there a way to "lock" the drift frequency

Bohdan Tashchuk tashchuk at easystreet.com
Sun Nov 16 21:48:59 UTC 2003

wayne wrote:

> This is why I'm wondering if there is a way to "lock" the drift
> frequency to always be within a certain range.

I agree with you.

I don't have problems as severe as you do, but from years of observing 
ntpd supplied with easch release of FreeBSD 3.x and 4.x (not sure about 
versions) I think my system would be more stable with a limiting 
algorithm that is a variation of your proposal. Something like:

	only change drift frequency by 1 ppm max per hour

This would avoid the occasional positive feedback I see (about 3 or 4 
times a year). When this occurs, the drift file changes something like this:

	 -13 starting value, very close to ideal for my hardware
	ntp steps time,
	sometimes this fixes oscillation, sometimes I need to reboot

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