[pups] Pre-startup questions

Robin Birch robin at ruffnready.co.uk
Sun Jul 2 18:25:08 AEST 2000

In message <20000701202457.A23817 at miyuki.genom.co.jp>, W . Suika Roberts
<ssfr at unm.edu> writes
>I just (yesterday) aquired a microPDP 11/73 -- it had been used by my
>school to operate some sort of geological test equipment that is no
>longer present, and was working when it went out of service, who knows
>how long ago.
So long as it was working when it was last connected it will probably
work when you switch it on.  these things are fairly reliable.  Once you
have worked out how to boot it you will probably need to get in and
disable the start-up sequence that probably loads the software to run
the test equipment that it was connected to.  Then you can look round
and see what you have got in the way of an operating system.

>She has a pair of RX02s, an RD52a inside her case, and that's all I've
>determined so far, since I haven't opened her up, really, yet.
Ok, an RD52 isn't very big, you will need to look at increasing that if
you want useful disk space.  The best disc will be an RD54 if the disc
controller supports it.  Failing that there are articles in the archive
(I think) about using non DEC discs with their controllers.

When you get round to adding operating systems and the like, a simple
tape controller and drive would be an advantage.  Anything like a TK50
or TS11 set up would help.

>I'm interested in documentation on monitor commands, what the boot
>sequence should look like, and other such software stuff right now.

Ok, some one can probably copy the docs for you.  For a start, when you
switch it on the monitor will show a boot sequence as it counts through
a set of numbers.  These are the internal tests.  during this list press
control C and a prompt should come up, then press H followed by return,
that should give you enough pointers to go through the on board help, a
little skimpy but its a start.

With luck you should be able to interrupt the boot sequence of the
operating system to prevent it going over to the final application.
This way you can have a see around inside and find out what OS you have
and start playing.

>I'm also wondering about useful things like: `Is the part number in a
>standard location on each card', `What is the form factor difference
>between Q-bus and Unibus', `Will starting her up trip the breaker', and
>`How much space is there in that little rackmount'

The part number is usually engraved on the handle of the card.  This
will be something like M7555.  There is a list in the archive that
should allow you to relate between these numbers and the card

Q BUS and UNIBUS cards have, in the quad versions, similar form factors,
however they are NOT interchangeable as the bus specs are totally

You should be able to put a singe BA23 box 11/73 into a domestic power
outlet without burning the house down.

You will probably find the bus has 3 or 4 spare slots.  This is based on
a processor card, say 2 memory cards, an MSCP (disc) controller and some
serial ports.  What ever the system was that it was connected to may
also have an interface card.

>In the near future, I'd like to find ethernet and SCSI adaptors for her,
>and so am wondering where parts might be aquired.
Both parts are available, ethernet is easy and comparatively cheap.
SCSI is easy and expensive.  You can get SCSI controllers for tape, disc
and both but be surprised at the price. There are many places that sell
boards for these beasts, some one in your area could give you much
better advice than me.

>       Suika (very happy) 

So I should think :-)

Robin Birch     robin at ruffnready.co.uk

M1ASU/2E0ARJ/M5ABD     Old computers and radios always welcome

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