On 3/22/2012 5:54 PM, David Lord wrote:
unruh wrote:
On 2012-03-22, David J Taylor <david-tay...@blueyonder.co.uk.invalid>
wrote:
"unruh" <un...@invalid.ca> wrote in message
news:xLHar.38386$iq1.34...@newsfe18.iad...
[]
Measure what? Why do you think that ntp reporting the offset with an
extra three decimal points would allow you to measure anything? What in
your mind would you expect to see in that output that would allow
you to
"measure" something that would tell you that the -19 was wrong?
Remember
ntpd DID measure something in order to determine that -19. What do you
think the extra decimal places would give you?
Most likely I would be looking at a histogram of the reported
offsets, and see whether it was gaussian, flat, or whatever, and how
wide. I might learn something from that.
No. Not if it is just noise.
Others have reported precisions better than -19, and also have a need
for greater reporting precision.
That is a valid issue.
I have servers currently with precision= of 18, 19, 20 but not
scanned back in history more than today. The value varies, with
temperature and system load which causes local temperature
variations. The precision values vary and are just way points.
With precision 20. I don't really need an extra decimal place
but in a previous life was used to throwing away two results
from five or more if from a greater number of samples.
My standard pc hardware can't do any better.
David
There seems to be an impression out there that I'm trying to show
something is wrong - I'm not. I suggested an enhancement so that the
precision of ntpq matched that of the loopstats. That's all.
precision is not accuracy.
In science we teach students not to report unwarranted precision-- the
precision should reflect the accuracy of the measurements. We keep
getting measurements to the mm and reported precision to angstoms
because that was what the calculator spit out. I am not averse to
reporting with a precion maybe up to a factor of 10
better than the accuracy, but any more is just silly and misleading (as
you are demonstrating in believing that a greater precision would convey
some extra information.
David
I remember this one from thirty or more years ago:
"Measure with micrometer, mark with chalk, cut with axe!"
_______________________________________________
questions mailing list
questions@lists.ntp.org
http://lists.ntp.org/listinfo/questions
