[ntp:questions] ntpd -q and driftfile

Karel Sandler sandler at ujf.cas.cz
Wed Mar 23 11:16:06 UTC 2011

On 23.3.2011 8:07, Hal Murray wrote:
>> You can probably do better than that. That is for the reaction to
>> something that you do not expect. Ie, you have decide that the event has
>> occured and then send the messages to your finger to press. However for
>> the timing, you know exactly when it is going to occur. You can get
>> yourself into a rhythm on each second, and then finally press the
>> button. So I suspect you can do about .1 sec if you try hard.
> That would be another good science fair type experiment.
> How long does it take to respond to a predictible event vs
> to an unpredictable stimulus.  What is the distribution?
Musicians in a good orchestra are synchronized within 20ms. On the other 
hand, reaction time for the event that is expected to occur is called 
personal equation. The value is usually in the range 0.2 or 0.3 sec. For 
example, chronographs used by amateurs for timing star eclipse by the 
Moon allow to measure this value. An experienced observer has stable 
personal equation when relaxed and focused.

Karel Sandler

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