[ntp:questions] Frequency Errors +500 PPM...

Richard B. Gilbert rgilbert88 at comcast.net
Thu Feb 3 22:42:32 UTC 2005


Kit Plummer wrote:

> FWIW, here is a snip of my ntp.log file:
>
>  3 Feb 10:00:14 ntpd[412]: kernel time sync enabled 0001
>  3 Feb 10:04:33 ntpd[412]: synchronized to GPS_BANC(0), stratum=0
>  3 Feb 10:36:45 ntpd[412]: time reset -0.873229 s
>  3 Feb 10:36:45 ntpd[412]: frequency error -512 PPM exceeds tolerance  
> 500 PPM
>  3 Feb 10:41:02 ntpd[412]: synchronized to GPS_BANC(0), stratum=0
>  3 Feb 11:47:44 ntpd[412]: no servers reachable
>  3 Feb 11:48:49 ntpd[412]: synchronized to GPS_BANC(0), stratum=0
>  3 Feb 12:03:51 ntpd[412]: time reset -0.871702 s
>  3 Feb 12:03:51 ntpd[412]: frequency error -512 PPM exceeds tolerance  
> 500 PPM
>  3 Feb 12:08:09 ntpd[412]: synchronized to GPS_BANC(0), stratum=0
>
> What can I do to control the PPM?  This is a SPARC-based VME board,  
> getting its clock from a VME-based SYNCCLOCK32 GPS/IRIG card.
>
> TIA,
> Kit
>
> On Feb 3, 2005, at 9:46 AM, Kit Plummer wrote:
>
>> Hey folks,
>>
>> I am having NTP prolbems.  Obviously.  But, I am not sure it is NTP,  
>> or my reference driver - or hardware for that matter.  The problem  
>> appears to be related to an extremely high PPM.  Am I understanding  
>> correctly that this number is derived from whatever is in the  
>> ntp.drift file?
>>
>> Well, the real problem appears to be a 1 second step - 
>> sporadically.   Though I haven't really been able to prove that 
>> either...it is just  heresay from a system user.
>>
>> Also,  can someone explain this output from ntpd -d:
>>
>> peer GPS_BANC(0) event 'event_reach' (0x84) status 'unreach, conf, 1  
>> event, event_reach' (0x8014)
>>
>> If there is some other information I can provide for troubleshooting  
>> purposes let me know.
>>
>> TIA,
>> Kit
>> ----------------------------------------------------------------------- 
>> -
>> Kit Plummer
>> Operations Research and System Performance Dept.
>> Raytheon Missile Systems
>>
>> _______________________________________________
>> questions mailing list
>> questions at lists.ntp.isc.org
>> https://lists.ntp.isc.org/mailman/listinfo/questions
>>
>
Please don't "top post".

Do you encounter this problem if you start ntpd with no drift file and 
with the clock set to within a few seconds of the correct time?   If you 
do, the first thing to do is to get the hardware fixed.  An error of 
512ppm works out to gaining or losing something like 48 seconds per 
day!   Now few people will argue that the typical undisciplined computer 
clock is not a  "POS"  but one that is that bad is definitely broken!

I've run ntpd on something like thirty different computers including 
Sun/Solaris/Sparc, Compaq/Solaris/X86, DEC Alpha/VMS and 
Compaq/RedHat/X86 without encountering this error.

Additional helpful information would include the hardware platform,  the 
operating system and version, and the version of ntpd that you are running.



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