pdp 8/e

From: Lawrence LeMay <lemay_at_cs.umn.edu>
Date: Wed Oct 6 18:36:56 1999

>
> >And one front panel switch is gone, and another is present but broken. The
> >rest at least appear to click up/down properly.
>
> I've got a spare switches in the darker orange but may not have one in the
> lighter yellow. Let me know if you'd like me to send them out to you.

The two bad switches are yellow ones. The switch mechanism is there, its
the paddle that is broken in one case, missing in the other. Though if I
cant get yellow someplace, then any color is better than a non-operational
computer...

>
> Tell us, did you get the "long" box or the "short" box? (the long box has
> two back planes in it connected by a row of jumpers.)

Long box, of course ;)

>
> This one:
> >M8655
>
> Is a serial port. (and the nicer one too!) You can run this one at RS-232
> levels right into your PC at 4800 or 9600 baud. See comments on Doug Jones
> and Aaron Nabil's sites for modifications and building cables.

And I just noticed that I actually have one usable cable, though it is very
short. It runs from one of the serial boards, to just barely out side the
back of the case, and it is labeled VT55. A white plastic connector, single
line of connectors, and if i recall correctly, 6 wires connected. Some
sort of current loop connector i'm assuming.

>
> These two:
> >M8360
> >M8350
>
> Make up a positive bus interface and a DMA (data break) card.

Which is nice. But what does this get me in the real world?

>
> This one I'm drooling over:
> >M840
>
> This is the high speed paper tape interface. It connects to the PC04
> reader/punch.

Yep. Unfortunately I dont have any peripherals. Except the one RL01, and
apparently I dont have an interface board for that.

>
> This is:
> >G111 Loose. 2 of these
> >G233 Loose. 3 of these (too bad they didnt leave the core planes)
> Parts for 2.5 8K core stacks. You need the H212 core mats to complete the
> picture.

I've always wanted a PDP8/e. Always. Which is why I already had in my
possession 2 complete 3 board sets of core memory, 8K per set, for the
PDP8/e! And I bought another 8K plane on ebay this summer. these things
tend to attract one another...

>
> All in all a pretty good catch. While it may be hard to get core for this
> thing you can find MOS memory systems at various places. The thing to worry
> about will be the top connectors. If you don't have them you can make them
> but it isn't fun. Some folks on the pdp8-lovers list might have spares.

I think I have enough. Not if I want to get a third set of core memory
installed, but its a long shot that the third set will work anyways. At
the very least the boards have to be tuned to work together, or some
such magic incantation uttered.

>
> Other questions:
> What was the date of manufacture? (on the back by PSU)
> Is the front panel lamps or LEDs?
>

Its standard pdp8/e lights as far as I know. Manufacture date is 1976.
If I read the codes correctly, its the 24th week of 76, and then some
other paper sticker on the top case, applied with scotch tape and only
partially still existing, mentions october 11, 1976, which I assume is
when some company then added their boards to make a specialized product.

One strange thing... The front panel doesnt say Maynard, Massachusettes, as
I expected... it says something like Galway, Ireland. Oh my GOD, its
the RARE Galway version! I can sell this on ebay and have more money
than Bill Gates! er, aHem.. I'm much calmer now...

Ok, so what do I need to obtain from here.. looks like I have the basics
of a PDP8/e system with serial ports. High speed paper tape reader interface,
but no paper tape reader... What would make this a minimal usable system?
Just adding a TTY33, and getting someone to copy a few paper tapes, perhaps?
If the core memory doesnt work out, is the MOS memory actually affordable?
Anyone willing to tell me some PDP parts suppliers that may have some
interface boards, like whatever I need to hook up that RL01 (what exactly
is a RL01 anyways). Maybe I should be looking to add floppy drives, etc.

OR, are people using IBM's as a terminal, and running some program that
pretends to be an attached paper tape reader/punch unit? That might do
for starters, though its not anywhere near as satisfying.

-Lawrence LeMay
Received on Wed Oct 06 1999 - 18:36:56 BST