[ntp:questions] ARRGH!!! I woke up to a 50 SECOND clock error.

Ron Frazier (NTP) timekeepingntplist at c3energy.com
Tue Mar 13 22:11:30 UTC 2012

On 3/13/2012 4:27 PM, David J Taylor wrote:
> "Ron Frazier (NTP)" <timekeepingntplist at c3energy.com> wrote in message 
> news:4F5F9233.1080204 at c3energy.com...
> []
>> The question is, what reset my clock abruptly 50 seconds off at 
>> around 0637 UTC.
> I would suspect your GPS.
>> My loopstats file shows that the GPS was humming along quite nicely 
>> at that point with no anomalies at all.  I don't believe it's the 
>> cause of the problem.  It looks like NTPD abruptly decided to step my 
>> clock 50 seconds, for reasons unknown.  As far as I know, NTPD is the 
>> only thing active on the system that will alter the clock.  The 
>> Windows internet time function is disabled.  The noselects are there 
>> for testing only.  I won't keep them there permanently.  I'm trying 
>> to determine where these anomalous readings are coming from.
>> Sincerely,
>> Ron
> Yes, I appreciate you are testing, but I think you are testing the 
> wrong way round (in view of the results).  Lock your PC as best you 
> can to the Internet servers, and watch the GPS with "noselect" against 
> it.
> Cheers,
> David

Hi David,

OK, you've convinced me.  I've put noselect on the GPS and taken it away 
on the New York NIST server.  The NY NIST server is now preferred and 
polling from 1 - 4 minutes.  Hopefully they won't ban me for hitting it 
too often.  I think the NIST server will have more jitter, particularly 
as the polling interval increases, but we'll see what happens.




(PS - If you email me and don't get a quick response, don't be concerned.
I get about 300 emails per day from alternate energy mailing lists and
such.  I don't always see new messages very quickly.  If you need a
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Ron Frazier
timekeepingdude AT c3energy.com

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