PDP 11/70s For Sale - test-drb@ccmp.vtda.org

24 Sep 1999

On Sep 24,  8:46, allisonp(a)world.std.com wrote:
...
  Subject: Re: PDP 11/70s For Sale
 > No, an 11/53 isn't an 11/23, it uses a J-11 on a board which also
includes
...
  > the RAM (typically 1.5MB) and its performance is
more like an 11/73 than an
...
  > 11/23.  You'd need BSD 2.11 to have any hope
of MSCP support for RDxx or
...
   RX50. 
 Didn't check the MicroPDP-11 book on this one.  All the 11/53 boxes I've
 seen either had 11/23B or the earlier no ram-nonPMI 11/73 cpu in them.
 Apparently that was a common configuration or the common path for the used
...
  boxes. 
The microPDP-11/53 uses a specific 11/53 CPU board design with a J-11,
SLUs, memory, and boot ROMs on one board.  There's no reason you couldn't
put an 11/23B in there instead, but 11/53s were never made with F-11
processors, so the ones you've seen must have been downgraded -- or have
had the badge replaced :-)  The cabinet is of course the same BA23 as the
microPDP-11/23 and microPDP-11/73.

...
  in any case most of the 11/23 or 11/73 cpus work quite
nicely in
 that box. 
They certainly would, of course.

-- 

Pete						Peter Turnbull
						Dept. of Computer Science
						University of York