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

unruh unruh at invalid.ca
Tue Mar 20 17:22:17 UTC 2012


On 2012-03-20, David J Taylor <david-taylor at blueyonder.co.uk.invalid> wrote:
> "unruh" <unruh at invalid.ca> wrote in message 
> news:JDU9r.22132$_C5.11432 at newsfe09.iad...
> []
>> Of course the question still is why in the world did the system go nuts
>> when it was on Local. That itself should not have happened.
>
> If some software had told the system clock to run fast, it simply stays 
> running fast, even on Local.

I have never had any machine whether running ntp, chrony or nothing,
result in a machine running a factor of thousands too fast. There is
nothing that I know of that would do that. Yes, if something told it to
advance the clock one hour per clock tick, it would do it. But you beg
the question, what would do that. 


>
> Ron is using a single GPS device, over USB, without the backup of a few 
> Internet servers to stop such a thing happening, and the GPS has already 
> shown itself to be problematical.  NTP would normally have simply rejected 
> the errant GPS data and not cause the PC clock to run wild, but without 
> the Internet servers as backup, what is NTP to do?  I don't think it has a 
> choice other than to believe the GPS, even if it's incorrect or faulty.

It is really really hard to imagine any gps device doing that. 

>
> Ron, perhaps in the future you could adopt a similar configuration to one 
> I've mentioned before - add some Internet servers with a long polling 
> interval as a second opinion for NTP:

>
> _________________________________________
> server  <ref clock stuff>
>
> server  0.us.pool.ntp.org  minpoll 10 iburst
> server  1.us.pool.ntp.org  minpoll 10 iburst
> server  0.uk.pool.ntp.org  minpoll 10 iburst
> server  1.uk.pool.ntp.org  minpoll 10 iburst
> _________________________________________
>
>
> using servers [network] local to yourself, of course.
>
> Cheers,
> David 
>



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