Hello, and please help with RSX-11M/PDP parts

From: Christopher Smith <csmith_at_amdocs.com>
Date: Fri Nov 16 10:10:50 2001

This will be a lot to cram into one mail, but here we go...

First off, Hi everybody. I'm newly subscribed to this list.

Next, I was wondering whether anyone here can help my with my newly acquired
(IE rescued from the crusher) PDP-11/73.

Straight to the point, I can get it to boot up RSX-11M, which is installed
on the fixed drive, and do *stuff*. (please correct me if I'm wrong on any
of this, by the way)

I've figured out that the previous owner has disabled logins from the
console port, perhaps to defeat the "forgotten password" procedure that I
can't get to work ;) I can hit ^C and get an "MCR>" prompt, but nothing
else.

There is another port which has user [10,10] logged in automatically when
the machine finishes booting, so I've been able to experiment with it some.
I've managed to figure out that INS and REM are MCR commands to insert and
remove images from the system. RUN seems to automatically insert, execute,
and perhaps afterwards remove an image. HEL will log you in (but not
without a password!), and BYE will log you out.

What I'm missing here are basically any file-management commands! :) Does
anyone have a short reference? I could also use suggestions on a recovery
procedure to get access to the 0,0 account.

Here are my thoughts:

Put the drive in a MicroVAX-II (write-protected!), in place of the
MicroVAX's system disk. MOPboot the VAX from another, larger VAX, and
<edit?/move/do-something-to> either the UAF or the startup files to change
the 0,0 password, or change the boot procedure so that the "forgotten
password" process will work.

(Anyone know if this is possible, or whether there's an easier way?)

My understanding of this "forgotten password" process is that you hit ^C
early in the boot procedure to get the "MCR>" prompt, and run the command
REM ...AT. to de-install the command-file processor so that the system can't
fully bring itself up. This somehow should cause the system to give you
privileged CLI access.

This system is a MicroPDP-11/73, with an "MFM" type fixed drive of unknown
size, two 4-port serial boards, and an RX50 (I think that's the strange
2-in-1 floppy drive?). It tells me on bootup that it's got 512k of RAM
"mapped." I've been assuming that this is the full amount of built-in RAM.
Please correct me if I'm wrong there. I'll get the CPU revision/OS
version/etc if needed, but I don't have the system handy right now.

Once I get the machine up and running, I'll need to make a good backup of
the drive, in some kind of bootable form, since it's the only copy of RSX
I've got. I hear there's a stand-alone BRU. Is that the way to go? It's
likely I'll backup to floppy, and image the floppies to CD. I may also
remove a tk50 and controller from a MicroVAX II, so that I can backup to
tape, and dump the tape into a file using one of my VAXen.

Given all of the above, any suggestions?

If I've kept your attention this far, let me also ask another, more
open-ended question.

I'd like to get an older, unibus based PDP-11 eventually. Ideally, here is
what I'd like:

Core memory
Programming switches on the front-panel
Reel-to-reel tape
Small package (meaning half-size to 2/3 size a normal rack. I've seen
pictures of things like this.
Some kind of disk storage
Multi-port serial

Any advice on collecting parts, or finding old parts/systems? I've already
been given, and taken the ebay advice. No luck there yet.

Regards,

Chris

Christopher Smith, Perl Developer
Amdocs - Champaign, IL

/usr/bin/perl -e '
print((~"\x95\xc4\xe3"^"Just Another Perl Hacker.")."\x08!\n");
'
 
Received on Fri Nov 16 2001 - 10:10:50 GMT

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