On Sep 24, 8:46, allisonp_at_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
Received on Fri Sep 24 1999 - 14:22:32 BST