"Brian Utterback" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
>> Here's the simple proof. The time is 5:15. One server says:
>>
>> 5:14 plus/minus 2 minutes
>>
>> The other says:
>>
>> 5:15 plus/minus 2 minutes
>>
>> Now, what can the third insane clock say that will make you think
>> it's any time other than 5:12-5:17?
> That's easy. How about 5:13 plus/minus 1 minute? Since you said the
> time is actually 5:15, this is by definition a falseticker, since
> the correct time is not within its interval. But the interval
> 5:13-5:14 overlaps all three servers, so this is where they
> all agree, so it must be where the correct time is, no?
5:13 plus/minus 2 minutes would be correct. Only one clock claimed an
accuracy window of one minutes. We can't base our conclusions on just one
clock.
It is possible that a naive algorithm could be mislead. However, it
cannot be mislead by much. Remember, part of the definition of an "accurate"
clock was that its confidence window was small. You've only thrown the clock
estimate off by that much. So you've thrown it off by a small amount.
Note that the correct time is 5:15 in the example. By definition, the
two minutes the two clocks is off are a "small amount". So any time between
5:13-5:17 would be acceptable, that is, off by only a small amount.
DS
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