On Thu, 6 Jun 2002, der Mouse wrote:

> Portability is not an all-or-nothing thing.  If you're accessing
> device registers on an SBus card, for example, it's probably safe -
> and certainly not unreasonable - to assume you're on a byte-addressed
> machine...even though code making such an assumption is "nonportable",
> and in a sufficiently wider context could be justly flamed for it.
> Much of NetBSD, for example, assumes that 8-bit, 16-bit and 32-bit
> types are available.  Some of this code assumes only that they're
> at-least-8-bit, at-least-16-bit, etc, but I think I've seen some that
> assumes they're exactly that size.  This will break badly if anyone
> tries to port it to (say) a 36-bit machine.  (ISTR hearing of a
> nascent NetBSD/pdp10 effort; wasn't the 10 a 36-bit machine?)

There's an ongoing effort to gather support and interest for a
NetBSD/pdp10 port, and god willing, it will happen.  I'd very much like
for us to test the limits of NetBSD's portability to an architecture
that doesn't rely on "n^2" word size assumptions.  Lars Brinkhoff has
sorted out a port of GCC for the PDP-10, so we've one hurdle fewer to
overcome in reaching the end goal.  Additionally, there are numerous
free PDP-10 emulators now, so the initial port would be to one or
possibly several of these.  More specifically, the port would be
targeting the KL10-E CPU which supported a 30-bit extended addressing
mode, 23 bits of which are available in practice.

Thanks to Anders Magnusson, there's now a port-pdp10 mailing list for
the port: <http://www.netbsd.org/MailingLists/#port-pdp10>.

-brian.