[ntp:questions] drift file set to -500

David J Taylor david-taylor at blueyonder.not-this-bit.nor-this-bit.co.uk
Tue Nov 27 06:54:07 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


I've seen something similar under Windows - known good hardware with drift 
values from 10 to 100.  Suddenly, NTP becomes confused, and sets the drift 
value to a an extreme (+/- 496, for example, I don't recall plus or 
minus), and cannot recover from it.  You need to delete the drift file, or 
enter a near correct value.

Of course, as Richard says, it could be a hardware issue, or it could be 
something in NTP.  What happens if you delete the drift file and leave it 
for a few hours?


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