In article <Pine.NEB.4.30.0101051729240.3735-100000@paper.durnsford.net> you write:
>I believe that certain arm32 and arm26 machines also have a host ID
>readable from hardware.
>
>These would be (IIRC) the RiscPC, the A7000 series, the A4000 and A5000,
>and the A30x0 (not including the A3000).

That's correct.

>I can't remember offhand how to reach these IDs, but Acorn called them
>Unique Machine IDs.

They're in a Dallas Silicon Serial Number chip (erm DS1401?) attached to
one of the control pins on the IOC/IOMD.  Access (as with the I^2C bus on
these machines) is by bit-banging over the control register.  Currently,
neither port has code to do this (arm32 gets the ID from the bootloader).

-- 
Ben Harris                                                   <bjh21@netbsd.org>
Portmaster, NetBSD/arm26               <URL:http://www.netbsd.org/Ports/arm26/>