New subject: PDP emulation & V7

6 Mar 2000

On Mar 6,  9:01, CLASSICCMP(a)trailing-edge.com wrote:
...
  >> I tried swapping my M8186 (11/23) for M8192
(11/73) but it doesn't run.
...
  >>  Maybe I need to rebuild the kernel (I've
got an original distribution, not
...
  >> one of the images from PUPS), but perhaps it
would work with more memory or
...
  > by
swapping RLV11 for RLV12. 
 >Cpu doesn't run or doesn't run V7?  The image I have only wants some
256k
...
  >of ram out of all teh installed ram.  I get the
impression it was
 >configured for an 11/34 or similar and that is mostly a 11/23 save for the
...
  >11/23 mmu can go to 22 bits. 
V7 doesn't run.  More precisely, it boots and starts the kernel but it
immediately panics.  I can't remember what the message was; it's a long
time since I tried it.

...
  The V6 and V7 images currently available have device
drivers that
 were built for Unibus systems.  They expect a Unibus Map to be present
 for accessing memory above 256Kbytes (many of the drivers were built to
 always expect a Unibus map).  The "safe" thing to do on a Q-bus system
 (or an emulated Q-bus system, like Supnik's emulator) is to run with 256Kbytes
...
  or less. 
It probably isn't memory, then.  It's probably down to something (maybe a
driver) that checks for something like the presence of a register, finds it
on my 11/73, and makes an erroneous assumption.  V7 predates the 11/73 by
quite a way, so that wouldn't be too surprising.

-- 

Pete						Peter Turnbull
						Dept. of Computer Science
						University of York