[time-nuts] sub-minute time-precision in court-case

Magnus Danielson magnus at rubidium.dyndns.org
Thu Sep 5 18:52:11 EDT 2013


On 09/04/2013 01:59 AM, Jim Lux wrote:
> On 9/3/13 11:21 AM, Poul-Henning Kamp wrote:
>> In message <5225F8AF.60807 at earthlink.net>, Jim Lux writes:
>>
>>> In this case, all the messages were presumably handled by the same
>>> carrier, so the issue of skew in timestamps is negligible;
>>
>> Anything but.
>>
>> The text-messages are likely stamped by the SS7-message-gateway
>> and the 911 call by the countys 911 equipment.
>>
>
> I was assuming (with no real basis, I realize) that the 911 call time
> came from the cell equipment, rather than the Public Safety Answering
> Point log.  The PSAP log would have no particular reason to be synced
> to the carrier equipment. It could well be "what time was on the watch
> of the guy starting the equipment", although these days, one would
> *think* that they use something like NTP to set the system time.
>
> However, given my frustrated experience trying to get folks doing
> testbeds and ground support equipment here at JPL to *please*
> synchronize your computers meaningfully so we can merge logs, I
> wouldn't count on it.  Or maybe they sync once every 24 hours.
That would be luxury! There are so many systems out there ticking away
at their free-running clocks, and that does not even have the capability
of an external time source.

Cheers,
Magnus


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