[ntp:questions] Resolution and Precision

David L. Mills mills at udel.edu
Wed Feb 14 17:11:33 UTC 2007


The terms time, epoch, resolution, precision, accuracy, time offset, 
frequency offset, jitter and wander are given precise definitions in the 
NTPv4 specification draft now linked from the NTP project page 


David J Taylor wrote:

> mills at udel.edu wrote:
>>RFC 1305 was the seat of furious controversy. I consider the only
>>authorative document is in PostScript, later in PDF. The IETF and I
>>have engaged in serious disagreement on PDF formats as against Postel
>>ASCII. Everything, and I mean everything today is in PDF - Governent
>>documents and forms, University documents and forms, IEEE standards,
>>ACM and IEEE publications and everything else I do is in PDF. So,
>>what you see is what you get. The PDF of RFC 1305 is on the NTP
>>project page.
> Thanks, Dave.
> I see that reference 25 points to:
>   Abstract: 
> http://www.eecis.udel.edu/~mills/database/rfc/rfc1305/rfc1305a.pdf
>   Body: http://www.eecis.udel.edu/~mills/database/rfc/rfc1305/rfc1305b.pdf
>   Appendices: 
> http://www.eecis.udel.edu/~mills/database/rfc/rfc1305/rfc1305c.pdf
> On page 11 of the body, the word "precision" is used in the context where 
> I would use "resolution".  It isn't used in the sense of "how close to the 
> correct time is this clock", which I might call accuracy.  Perhaps it 
> would be helpful to have these terms defined somewhere?  Perhaps the terms 
> are used differently by different cultures, even!
> Cheers,
> David 

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