[ntp:questions] ARRGH!!! I woke up to a 50 SECOND clock error.

Chris Albertson albertson.chris at gmail.com
Thu Mar 15 19:45:40 UTC 2012

> Basically you have a trade-off between frequency error and time offset.
> IIRC, polling quickly will reduce the offset, but you get greater frequency
> variations.

There is nothing magic about NTP.   You have the exact same trade off
if you try and sync your wrist watch to the big town clock on the

If you look at the tower every hour and set the wrist watch to match
you will have very small offset between the watch and the big clock.
But if you do this the _rate_ of your wrist watch will never be
spot-on except by luck.

On the other hand if you sync your watch once then wait a week or a
month to see how much it has gained or lost you may see quite a bit of
"offset" but now you have good data on the relative rates of the two

NTP did not invent this trade off, it existed 200 years ago.

Chris Albertson
Redondo Beach, California

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