Subject: Re: DEC 5000/260 support?
To: Chris Tribo <>
From: Maciej W. Rozycki <>
List: port-pmax
Date: 11/16/2000 20:11:10
On Thu, 16 Nov 2000, Chris Tribo wrote:

> > The rule with intermixing 32 Mb and 8 Mb SIMMs is that if 32 Mb SIMMs
> > are present then only a sinlge 8 Mb SIMM may be fitted, and only in the
> > highest slot number (14).  As far as I am aware this is a
> > hardware/firmware limitation and nothing to do with the O/S you are
> > running.
> 	Someone here was working on a kernel that could use intermixed
> modules, so I think it's an OS issue with address space. Where 8MB and
> 32MB modules use the same address space. It wouldn't be that hard to
> figure out if you have an 8MB module and tell the kernel how to map it
> appropriately IMHO, but I'm not a programmer yet.

 REX provides a call-back function that returns a memory bitmap, with
occupied areas marked by ones and holes marked by zeroes.  It's documented
in the TC firmware specification and it works reliably on my /240 (I have
3*32 + 4*8).  An implementation is trivial. 

+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+        e-mail:, PGP key available        +