[ntp:questions] Time slew doesn't seem to work

David Woolley david at ex.djwhome.demon.co.uk.invalid
Fri Apr 11 21:09:42 UTC 2008


David L. Mills wrote:

> The default step threshold is 128 ms; the -x command line option sets it 
> to 600 s and does nothing else. The 600-s value was chosen as the 

Oops, I thought the units there were ms, which invalidates some of what 
I said.  I was probably partly confused by the disabling of the kernel 
discipline at 0.5 seconds.


> expected accuracy with eyeball and wristwatch. If the extra pole is not 

With a radio controlled wrist watch, 200ms is easily possible.  I'd 
suggest that 10 minutes is about the 95 percentile for when the person 
setting the time doesn't care about the time.  In that context, my 
practical experience is that most times are set within 5 minutes.  As 
someone who regularly uses public transport, I would be disappointed if 
I could get the time to 30 seconds, by reading my wrist watch.

600 seconds is 60% of the drop dead value, so I'm not clear why the two 
weren't made the same.




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