[ntp:questions] ntpd wedged again

A C 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.

More information about the questions mailing list