[ntp:questions] refclock on Windows graphs

David J Taylor david-taylor at blueyonder.neither-this-bit.nor-this.co.uk
Fri Mar 20 15:53:30 UTC 2009


Unruh wrote:
> "David J Taylor"
[]
>> I put the temperature graph next to the timekeeping graph here:
>
>>  http://www.satsignal.eu/mrtg/performance_feenix.php
>
>> but I think that ambient temperature would be much more useful than
>> HDD temperature.
>
> Unfortunately the scale on the graph is a bit useless (the variation
> is
> squeezed up far too much).

Yes, and no.  It's MRTG, so it's going to plot from 0, and if the 
variation isn't as much as even 5 degrees then I think I need to look at a 
different measurement.  As a quick fix, we have to make do with what we 
have.

> Also It is not at all clear what the
> "Timekeeping" graph is a graph of. Is that the offset, the drift rate
> correction? And what is 5001's ? (the quoted offset) It is the drift
> rate
> that should correlate with temp.

Timekeeping is the offset.  The original graph had "offset + 500us" where 
the "u" was the micro symbol, but while that has displayed correctly in 
most of the place, it has failed on the graph Y-axis label.  I'll replace 
"micro" with "u".

> It is certainly true that something like disk temp is a best a poor
> proxy
> for the timing crystal temp. esp since the disk is probably not the
> main
> heat source. The CPU temp would rpobably be a better proxy, but
> obviously
> even that is not very good. "motherboard temp" might be better.
> Anyway, by plotting both the drift rate correction and the temp of
> these various
> locations you could get a better idea of which correlated best with
> the
> timing crystal rates.

Thanks for your input, Bill.  If I can get a more accurate temperature, I 
will look into plotting the offset on MRTG as well, or using a better 
plotting program.  For me end use, though, it's the offset which matters.

Cheers,
David 




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