In article <20070308074552.192f826a@hal.xisop> you write:
>Or if a specific address
>had to be decided on, would there be an arch-independent address that
>would suit this?  Would using "page 0" for this be out of the question?

Yes, for at least two reasons.  First, it's very helpful for null 
pointer dereferences to give a segfault rather than returning garbage.  
Second, on older ARMs (and possibly other CPUs) zero page is used to 
hold CPU exception vectors and fast interrupt handlers, so there isn't 
a lot of space for other purposes.

-- 
Ben Harris                                                   <bjh21@NetBSD.org>
Portmaster, NetBSD/acorn26               <http://www.NetBSD.org/Ports/acorn26/>