Building a PDP-11 for the first time

From: Jerome H. Fine <jhfinexgs2_at_compsys.to>
Date: Thu Dec 11 16:23:08 2003

>Christopher Cureau wrote:

> Finally! Instead of just working on one, I'm going to try to build one
> from some components that I've collected. Trouble is, I'm not sure how to
> put it all together. I saw mention of a QBUS howto, but the link to that
> seems to be long gone. Would a kind soul care to assist on this?
> This is what I have:
> BA23 enclosure
> M8190-AB (11/84 cpu)
> M8067 (512k memory?)
> M7516 (DELQA)
> Dilog DQ686 (ESDI controller)
> Maxtor ESDI drive (don't remember how large offhand)

Jerome Fine replies:

First, the M8190-AB is a PDP-11/73 CPU board and
usually runs in an ALL Qbus system. Don't forget that
the M8190-AB runs BEST with a cabinet kit that has
ONE DB25 connector and two cables between it and
the CPU - one 10 pin and one 20 pin.

Extra M8067 memory boards of 1/2 MByte should
not be too difficult to find.

All of the above hardware is compatible. The M8190-AB
is DEFINITELY a Qbus board, NOT a UNIBUS board.
In fact, it is not even a PDP-11/83 CPU, but normally
regarded as a PDP-11/73 CPU, in RT-11 noted as a
B processor since it has boot ROMs and all that sort of
stuff. Under RT-11 when used with normal memory
or PMI memory below the CPU, it is a PDP-11/73.
When used with PMI memory above the CPU, RT-11
shows a PDP-11/83 to be present.

In addition, as has been noted, there is no such animal
as a PDP-11/84 CPU since the same CPU board is
used for BOTH the PDP-11/83 and the PDP-11/84.

However, in the ALL Qbus or PDP-11/83 system,
the same PMI memory will also work with most
M8190-AB boards either as normal memory or
a PMI memory - depending on the position whether
the memory is above or below the CPU.

When used in a PDP-11/84 system, the PMI memory
is different and the rest of the system is Unibus with
a converter connected to the CPU / memory on the
Qbus side.

I have no idea of how to transfer BSD to the hard drive!

Even RT-11 would be difficult since there are no easy
ways without RT-11 to do a download.

Having an RQDX3 and an RX50 in the BA23 box
might be useful.

> I'm thinking that I have all that I need here, but I could be wrong. I
> want to be able to run 2.11BSD on the machine...
> Cheers,
> Chris Cureau

Sorry - I am an RT-11 addict!

Sincerely yours,

Jerome Fine
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Received on Thu Dec 11 2003 - 16:23:08 GMT

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