PDP-11/73 booting!

[Pete Turnbull]

On Dec 12 2005, 21:17, Allison wrote:

> I did say 73B didn't I?  There were two different J11 cards, I am
using
> the M8190 KDJ11-B which is Q22.  However there is a later J11 that
uses
> the PMI memory.  I have memory for that one but not the CPU.

Yes, you did say 73B.  As I'm sure you know, there were two 73s, one
dual M8192 and one quad M8190.  The dual is QBus only, naturally, no
PMI.  The 83 is also quad, and is the same M8190 card as the 73, but
with a faster clock (the earliest J11s won't run reliably at 18MHz let
alone any faster) and slightly different bootstrap ROMs.  73 was sold
as a 15MHz non-PMI system and the 83 as 18MHz PMI, but in fact you can
move the 73 card below the memory instead of above it and it will work
(if the memory is PMI, anyway!).  In fact the OSs distinguish 11/73
systems from 11/83 systems simply by checking if they're using PMI.


-- 
Pete						Peter Turnbull
						Network Manager
						University of York