[ntp:questions] Synchronize clocks without a reference clock

Richard B. gilbert rgilbert88 at comcast.net
Mon Mar 19 14:37:30 UTC 2007

Maarten Wiltink wrote:
> "Spoon" <devnull at localhost.com> wrote in message
> news:45fe6248$0$27199$426a74cc at news.free.fr...
>>Maarten Wiltink wrote:
> [...]
>>When you say that the clock in a server next to a door will wander a
>>lot, are you referring to the effects of the sudden temperature swing
>>when a cold draft comes in the server room?
>>Does this mean that the maximum rate of change is 15 µs per second?
> No, that's something else, probably the worst-case estimate for how
> fast synchronisation deteriorates between server polls. But that's no
> more than a guess.
> The number I mean is the 500PPM cap on the observed drift that NTP will
> accept before giving up. You can't change that without recompiling, IIAMN.
> Groetjes,
> Maarten Wiltink

500PPM is the limit to the rate at which the clock can be slewed in most 
operating systems.  Recompiling will not help.  Modifying the O/S kernel 
and rebuilding the kernel MIGHT help. (I've never heard of anyone having 
done this.)  If the system is that badly broken it's probably easier to 
have the hardware repaired.

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