An ontology of clocks

[Kurt Roeckx]

On Fri, Feb 19, 2016 at 03:19:01PM -0800, Gary E. Miller wrote:
> Yo Daniel!
> 
> On Fri, 19 Feb 2016 18:12:52 -0500
> Daniel Franke <dfoxfranke at gmail.com> wrote:
> 
> > On 2/19/16, Gary E. Miller <gem at rellim.com> wrote:
> > > No, resolution is the smallest time increment a clock can represent.
> > > Precision is a measure of the quality of the clock time.  
> > 
> > I've seen "precision" used both ways by different authors, but I think
> > you're right that resolution is a better choice of terminology because
> > it avoids that ambiguity.
> 
> 
> Yes, people get sloppy, but since we are on the ntpsec mailing list we
> should prolly to stick to the NTP definitions.
> 
> According to ntp.org:
> 
>     http://www.ntp.org/ntpfaq/NTP-s-sw-clocks-quality.htm
> 
>     "The smallest possible increase of time the clock model allows is
>     called resolution."
> 
>     "Precision is the random uncertainty of a measured value, expressed
>     by the standard deviation or by a multiple of the standard
>     deviation."
> 
>     "Accuracy is the closeness of the agreement between the result of a
>     measurement and a true value of the measurand."

And that is not even specific that NTP, that's just what those
terms mean.  But you can argue how you express the precision
exactly, and standard deviation is probably the easiest to
understand and what most people will care about.

(I was also about to comment about this, but then saw the other
mails.)


Kurt