[ntp:questions] ntpd wedged again
agcarver+ntp at acarver.net
Thu Feb 9 20:17:20 UTC 2012
On 2/9/2012 05:04, Dave Hart wrote:
> On Thu, Feb 9, 2012 at 03:47, A C<agcarver+ntp at acarver.net> wrote:
>> The latest version is now compiled and running. I'll let it go and see what
>> happens over the next week. Just as a point of reference, the system has
>> been without ntpd (or any other clock discipline) for about three days and
>> the clock was only off by about 1 millisecond when I started ntpd up again.
>> So it would appear that the system oscillator is reasonably stable and I
>> don't have to be as concerned that it's doing something strange to cause the
>> multi-second jumps.
> Agreed. Assuming the IPX is using the typical crystal oscillator and
> not something temperature-controlled or compensated, it also indicates
> that crystal has had remarkably stable temperatures over those three
> days, and that the last run of ntpd ended with a well-honed frequency
> correction for it to freewheel so accurately.
I think it has to do with the air flow through the case that keeps the
internal case temperature rather stable. I have temperature records of
the room (one sample every two minutes) and there was a 10 degree
Fahrenheit shift over the course of each day. So not too bad, I'll take it.
The oscillator is a typical four pin flat-pack with the on-board drive
circuit, amplifier, pulse shaper, and TTL output driver.
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