[ntp:questions] Which ntp driver?

Danny Mayer mayer at ntp.isc.org
Sun Apr 2 14:53:56 UTC 2006

Some of this really belongs in hackers and some in the ntp WG.

For example I don't think that burst/iburst has a real meaning for a
refclock since it's constantly feeding ntpd data.

Greg Dowd wrote:
> Dare I admit that I haven't climbed the Wiki mountain yet?  It seems to
> be a contentious issue.  Having said that, I'm all for notes on
> application and suitability of the refclock drivers as well as common
> usage.  It would be nice after the release comes out to review, or
> debate, the future of refclock drivers and their format.   Dave's How to
> build a refclock driver has been around for quite a while and is not
> quite accurate anymore.  Moreso if the configuration structure changes.
> Of course, no one wants to change the existing stuff and possibly break
> a legacy application but maybe we could deprecate some of the drivers.  
> Things I have thought about (in no particular order):
> Do they all have to work forever?  
> Could we get burst/iburst to apply -or- Is there any reason to cap
> minpoll. on a refclock (w/in reason)
> Are we stuck in pll mode with high update rates.  Can I use a different
> filter on a refclock?
> Is there a limitation on the number of useful samples I can capture per
> poll (e.g. acts)
> Does the prefer keyword work properly for refclocks? (to prevent
> ensembling)
> Can we please stop getting year from the host processor (when year is
> available in driver) [make -g work for refclock]
> Clarify the required data in refclock driver (and what is
> dynamic/static) [e.g. I change refid on fly]
> Add a private memory pointer to refclock structure to hold my data.
> Greg Dowd
> gdowd at symmetricom dot com (antispam format)
> Technologist, TT&M Div.
> Symmetricom, Inc. 
> www.symmetricom.com
> "The current implementation is non-obvious and may need to be improved."

More information about the questions mailing list