> * Lack of nanosecond granularity timekeeping (and Dave Mills'
>   "nanokernel" code) is a significant black mark against NetBSD, for
>   high-precision NTP users.

How close together are these systems?
The speed of light is about a foot a nanosecond, special relativity
makes a mockery of trying to get anything that synchonised using
anything network protocols.  You would need a carefully crafted
clock distribution circuit to directly synchonise hardware.

Otherwise you just can't get a message from machine A to machine B
and back to machine A in less than the time tick interval.
For microseconds the limit (assuming no cpu time in either system
and infinitely short network packets) would be about 400ft.

A 100MHz ethernet packet is >200 meters long.
IIRC GigaBit packets are not much shorter - the minimum size
(on the wire) is more bytes than 10M or 100M.

It doesn't make sense to attempt nanosecond synchronisation
using these techniques - and for the things the kernel uses
timestamps for.

	David

-- 
David Laight: david@l8s.co.uk