[ntp:questions] drift file set to -500

Richard B. Gilbert rgilbert88 at comcast.net
Tue Nov 27 02:51:38 UTC 2007

Aggie wrote:
> After running NTPD on VxWorks for a couple days, the ntp.drift file
> was set to -500, that made it jump to the infinite loop trying to call
> adjtime(), but VxWorks doesn't have adjtime().
> I read the ntp documentation. It suggests to disable the time-of-year
> (TOY) clock chip. How do I disable this clock chip??
> Have anyone seen this "-500" error before? How did you resolve this?
> Any advice help,
> Thanks
> Kev

500 PPM is the maximum frequency error that ntpd can compensate for. 
Typical computer clocks exhibit an error of 25 to 100 PPM.  The fact 
that your drift file contains -500 strongly suggests a severe hardware 
problem with your clock!  How much does it lose or gain per day when 
ntpd is not running?

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