[ntp:questions] Is 24PPM an Excessive Real-Time Clock Correction?

David Woolley david at ex.djwhome.demon.co.uk.invalid
Tue Jul 10 20:15:14 UTC 2007

In article <f70lui$1ntb$1 at ns.felk.cvut.cz>,
Karel Sandler <sandler at ujf.cas.cz> wrote:

> A question, please: how can I pick up and localize the clock the ntpd is 

Not quite sure what this means...

> based on (in order to measure the temperature of its crystal). The systems 
> used are Linux or FreeBSD.

On most motherboards, there are only two crystal oscillators, a slow one
servicing the RTC and a fast one serving all, or most, of the others.
HPET may be an exception on some machines, but I would note that high
precision doesn't actually mean high accuracy, so there is no need to
use a different oscillator, unless HPET is a misnomer.

Many people take a hardware view of clocks, in which case these
oscillators are the clocks, but the 6 clock article is taking a somewhat
different view, or was written without sufficient depth of knowledge to 
realise that a common timebase is used for many of them.


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