[ntp:questions] PSYCHO PC clock is advancing at 2 HR per second
unruh at invalid.ca
Tue Mar 20 20:22:33 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:Ur4ar.15722$IQ1.15335 at newsfe18.iad...
>> On 2012-03-20, David J Taylor <david-taylor at blueyonder.co.uk.invalid>
>>> "unruh" <unruh at invalid.ca> wrote in message
>>> news:d13ar.7952$GV1.7243 at newsfe12.iad...
>>>> It is really really hard to imagine any gps device doing that.
>>> Yes, I agree, and yet what just popped up in my mail box but a
>>> "an inexplicable 1 second slip of 3 GPS based NTP time sources".
>>> I have, of course, asked for more details!
>> A one second slip I could understand-- eg Gamin 18x reporting over 1
>> second after the associated second would lead to that. But a computer
>> advancing at an hour per tick is way beyond that.
>> Perhaps the 1 second slip tickled a bug in ntp with the LOCL clock--
>> where the system then saw the GPS as a false ticker, went to LOCAL with
>> a bad rate, and compounded the rate error by some sort of runaway
> You are confusing two events here. Ron had a problem with the PC running
> fast. This was a separate incident where there was a 1 second slippage.
> When and if I get more details I will post them here. There is no
> suggestion that the two are related.
No confusion. I understood completely. Ron had a machine on GPS which
ran away. You got a report of a 1 sec slippage. The question is whether
or not a 1 sec slippage in the GPS could trigger a runaway on a machine
which also had LOCL as a server. I simply do not believe that the GPS
sudenly went wild and delivered time at a rate 1000 times the UTC rate.
Something on his system triggered and instability, and all he had
running was a GPS and the LOCL server. Now, usually the machine would
take the GPS signal and it certainly could not engage in that kind of
runaway behaviour. It could however engage in something like a 1 sec
slippage. How could that trigger an instability?
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