I'd like to study the low level details of modern OS features
(Virtual memory, context switching, device drivers, etc...).
Of course I plan to use NetBSD ;)

I'm looking for the simplest architecture.
I'm aware of the inherent complexity of these topics but
I want to avoid "unnecessary" complexities (like those of i386
which is so encumbered with legacy issues).

I've already had positive advices about MIPS and Alpha ...
are there other alternatives ?

Concerning MIPS, what seems to be the "best" available
machine (regarding simplicity of the processor and/or
simplicity of installing NetBSD)?
Is SGI a good choice? Indigo or Indy ?

Advices would be appreciated.

TIA
Thierry Lacoste.