[ntp:questions] PSYCHO PC clock is advancing at 2 HR per second

unruh unruh at invalid.ca
Tue Mar 20 05:34:05 UTC 2012

On 2012-03-20, Ron Frazier (NTP) <timekeepingntplist at c3energy.com> wrote:
> Hi Dave H,
> Thanks for the info and for looking into the issue.  I meant that the 
> clock was psycho, not the PC.  The PC is normally very tame and 
> cooperative, as cooperative as Windows gets anyway.  These GPS 
> experiments have certainly brought several surprises though.
> I run both Windows and Ubuntu Linux, but in this case, the system is:
> Windows 7 Home Premium SP 1
> NTPD 4.2.7p259
> LOCL has been removed.  However, that brings up a question.  Since I'm 
> doing tests with the internet clocks noselected (but still monitoring 
> them), and the GPS is the only selectable clock, what happens if it 
> becomes invalid?  The whole reason I put LOCL in there was to allow the 
> machine to "coast" if the GPS signal became invalid.

It will coast on its own. There are millions of machines out there that
do not run ntpd and keep time reasonably well. They "coast" fine. 


> How would I go about checking the event log?
> Sincerely,
> Ron
> On 3/19/2012 10:59 PM, Dave Hart wrote:
>> Ron,
>> I don't know what the heck happened either, but there are a few clues.
>>   You didn't tell us which version of ntpd you're using or which OS
>> it's running on.  Skimming the huge ntp.conf for non-comment lines I
>> see it appears to be some version of Windows.
>> Take note of the last line in the first loopstats file you sent:
>> 56005 85287.065 -1.#IND00000 -1.#IO 0.003538719 -1.#IND00 3
>> There is no activity in the corresponding peerstats file to give a
>> hint what sent your offset and frequency off the deep end.  You might
>> check the eventlog around the end of the 19th UTC to see if there are
>> any clues there.
>> Although it's the first time I've seen such, it appears the offset and
>> frequency calculations both ended up overflowing.  I would have
>> guessed bad input should have appeared in peerstats before loopstats
>> but I didn't find anything unusual.  It does appear the GPS was
>> unplugged or stopped sending or sent sentences indicating no lock,
>> based on the last peerstats entry for occurring almost
>> exactly 5 minutes before the overflow event.
>> Probably we should just write it off as nominal since the PC is
>> described as psycho.
>> Take care,
>> Dave Hart
>> On Tue, Mar 20, 2012 at 01:59, Ron Frazier (NTP)
>> <timekeepingntplist at c3energy.com>  wrote:
>>> Hi all,
>>> I just came home from supper to the most NOT charming experience.  I had
>>> left with my PC clock syncing nicely to my Globalsat BU-353 GPS.  When I
>>> came home, I found the clock said Aug 2014 and visually could see that the
>>> clock was advancing at a rate of about 2 HR per actual second.  The Meinberg
>>> screen said it was locked into the local clock and the Meinberg screen
>>> appeared to be updating about twice per second rather than once ever 10
>>> seconds.  It said that the preferred clock was LOCL  I don't
>>> know what the heck happened, but these anomalies are getting really old.
>>>   Hopefully the Sure board will do better.  Oh, by the way, I shut down NTPD
>>> and the clock kept advancing the same way.  2 reboots appear to have fixed
>>> it.  I've removed LOCL from the config file.  Here are some links to some
>>> log and conf files if anyone is interested.  Note the dates at the end.
>>>   I've got 1200 log files in between these start and end dates.
>>> http://dl.dropbox.com/u/9879631/ntp.conf%20psycho%20clock
>>> http://dl.dropbox.com/u/9879631/loopstats.20120319-2-above-priority-gpgga96-poll-3-6%20psycho%20clock
>>> http://dl.dropbox.com/u/9879631/loopstats.20120320%20psycho%20clock
>>> http://dl.dropbox.com/u/9879631/loopstats.20120321%20psycho%20clock
>>> http://dl.dropbox.com/u/9879631/loopstats.20120322%20psycho%20clock
>>> http://dl.dropbox.com/u/9879631/loopstats.20120323%20psycho%20clock
>>> http://dl.dropbox.com/u/9879631/loopstats.20140112%20psycho%20clock   note
>>> the date far into the future
>>> http://dl.dropbox.com/u/9879631/loopstats.20140113%20psycho%20clock
>>> http://dl.dropbox.com/u/9879631/peerstats.20120319-2-above-priority-gpgga96-poll-3-6%20psycho%20clock
>>> http://dl.dropbox.com/u/9879631/peerstats.20120320%20psycho%20clock
>>> http://dl.dropbox.com/u/9879631/peerstats.20120321%20psycho%20clock
>>> http://dl.dropbox.com/u/9879631/peerstats.20120322%20psycho%20clock
>>> http://dl.dropbox.com/u/9879631/peerstats.20120323%20psycho%20clock
>>> http://dl.dropbox.com/u/9879631/peerstats.20140824%20psycho%20clock   note
>>> the date far into the future
>>> http://dl.dropbox.com/u/9879631/peerstats.20140825%20psycho%20clock
>>> Sincerely Frustrated,
>>> Ron

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