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A look at a great PDP-8 collection

C

Crawford

Experienced Member
Joined
Oct 21, 2008
Messages
275
Location
Maryland
Folks,

I had a great opportunity to visit with David Gesswein this last Saturday and see his PDP-8 collection. Dave has a great site at http://www.pdp8.net. Dave displays his systems at VCF East, and if you get the chance to meet him and see his systems, you should definitely do so.

Well I didn't make VCF this year (again), so after a few emails arranged to drop by since he's local to me. We mainly played with the PDP-8/I and the PDP-8/E. David even loaded up SpaceWars and we played several rounds (my favorite trick was to fly into the sun before David could shoot my ship). David showed me the music-playing program, his plotter, he loaded paper and mag tape programs, used the ASR-33 TTY. Yeah, I was there a long time.. I'm surprised he put up with me that long.

It's amazing what discrete components (transistors, diodes, resistors) in the case of the 8/I or medium scale IC's in the case of the 8/E can do. It definitely got me fired up about getting an -8 series !

-Crawford
 
Crawford said:
Folks,

I had a great opportunity to visit with David Gesswein this last Saturday and see his PDP-8 collection. Dave has a great site at http://www.pdp8.net. Dave displays his systems at VCF East, and if you get the chance to meet him and see his systems, you should definitely do so.

Well I didn't make VCF this year (again), so after a few emails arranged to drop by since he's local to me. We mainly played with the PDP-8/I and the PDP-8/E. David even loaded up SpaceWars and we played several rounds (my favorite trick was to fly into the sun before David could shoot my ship). David showed me the music-playing program, his plotter, he loaded paper and mag tape programs, used the ASR-33 TTY. Yeah, I was there a long time.. I'm surprised he put up with me that long.

It's amazing what discrete components (transistors, diodes, resistors) in the case of the 8/I or medium scale IC's in the case of the 8/E can do. It definitely got me fired up about getting an -8 series !

-Crawford
Click to expand...

Well, I'd not say the 8i was discrete components. It uses the same stuff the 8e does.
It just used the smaller flipchips since the backplane was not an Omnibus so had to
be wired for what flipchip went where. But I do agree these were pretty amazing
in their day. Of course it was all text based programming, but I had much fun then
and I still do now. I hope to get my 8i more memory and some sort of storage eventually.
My 8e is fully functional and I can even play Adventure on it. :) If you are patient your
8e (most likely) will come along.
 
No doubt, David has a beautiful collection. He has seemingly infinite attention to detail in his restorations. His website is a wealth of information for all the rest of us who love our machines too.

Lou
 
Yep, the 8/I was mostly MSI Medium scale integration

Yep, the 8/I was mostly MSI Medium scale integration

I stand corrected. Of course the 8/I was mostly medium-scale integrated circuits... on smallish circuit boards, plugged into a massive wire-wrapped backplane that was the electrical equivalent of a modern motherboard. Still - a *lot* of circuitry and interconnections. Oh and you want blinkenlights? How about a row of lights for every register? It made the 8/e seem cheap, but I guess that was the point of the 8/e in the first place: easier to build = cheaper to make.
 
Crawford said:
I stand corrected. Of course the 8/I was mostly medium-scale integrated circuits... on smallish circuit boards, plugged into a massive wire-wrapped backplane that was the electrical equivalent of a modern motherboard. Still - a *lot* of circuitry and interconnections. Oh and you want blinkenlights? How about a row of lights for every register? It made the 8/e seem cheap, but I guess that was the point of the 8/e in the first place: easier to build = cheaper to make.
Click to expand...

If you want a discrete 8, then you need to locate a straight 8. But good luck on finding
one, and if you do it will cost your an arm and a leg.

I myself love the 8i, but then I learned computers on one back in the early 70s. I like
the full front panel. I do like having to turn a knob to see a specific register. That is my biggest complaint about the 8e. If I could connect and 8i panel to an 8e I would be very happy. But the 8i panel pales in comparison to the ka-10 panel. :) I think that is the nicest panel DEC ever made.

Yes, Dave has a great collection of 8, and takes very good care of them. And restores them to the utmost detail. I did get to VCF East this year. Never made it the previouis years, but regretted it after. It was amazing the got that TU-60 working. And a sight to
see. I can only imagine what he will bring next year.
 
Actually it was a TU10 magtape drive that David got working. I have a TU60, which is a cassette tape drive (way less cool). Of course, David did bring a TU56, which is coolest of all.

Lou
 
I'm quite envious of your visit. His homepage is very helpful and I really enjoyed running his 8/e over the web last Christmas, very cool.

Speaking of KA-10 panels, do you still have yours Crawford?
 
Lou - N2MIY said:
Actually it was a TU10 magtape drive that David got working. I have a TU60, which is a cassette tape drive (way less cool). Of course, David did bring a TU56, which is coolest of all.

Lou
Click to expand...

Sorry, I was entering that post from work early this morning. I can never keep all the
options straight. Yes, the tape drive was very cool. Of course a TU56 is always neat
too. Some day I hope to get mine fully working. Nothing like seeing both drives work
at the same time. I guess the winter projects are often pdp-8 related since I don't
want to go out in the cold. I have never seen a TU60.
 
Tim,

Well, someday when I get the RK8E/RK05 restored, you'll have to come up to see the setup. It's not as impressive as yours, but it's still fun. The TU60 is pretty slow, but it does work.

For those who don't know, the TU60 is a datacassette drive. Although it uses Philips compact cassettes, it writes to the tape as if it was a little tape drive. It doesn't have capstans, the tape is held in tension by the reel motors. It was designed by the same guy that designed dectape (Tom Stockerbrand).

Pontus,

I have the KA10 console: http://www.vintage-computer.com/vcforum/album.php?albumid=2&pictureid=66

Lou

Lou
 
Lou - N2MIY said:
Tim,

Well, someday when I get the RK8E/RK05 restored, you'll have to come up to see the setup. It's not as impressive as yours, but it's still fun. The TU60 is pretty slow, but it does work.

For those who don't know, the TU60 is a datacassette drive. Although it uses Philips compact cassettes, it writes to the tape as if it was a little tape drive. It doesn't have capstans, the tape is held in tension by the reel motors. It was designed by the same guy that designed dectape (Tom Stockerbrand).

Lou

Lou
Click to expand...

I will have to take you up on that. Just let me know when. I hope the problem with
the RK8e is just a minor fix. I never looked into it. I know it did not run the non-disk
diagnostics, so that leads me to believe that one or more of the control registers may
be flaky. I happened to have a spare RK8e so used that instead and put the other
aside.
 
Tim,

Well, we have not yet begun to work on it in earnest. I thought I'd get the RA80 going first, which I have, and clear some other projects out. The RK8E is coming up soon though.

Annoyingly, my DSD440 (RX02 work-alike) needs to have the drive heads aligned. (anyone have an extra Shugart SA120 alignment diskette?) I may do that first to make loading the maindecs easier. I am afraid this is the punishment I get for keeping the equipment in the unheated garage. It swings from about 35 to 90F over the course of the year.

Here is a photo of my 8/e with TA8E/TU60 and the DSD440. The TU60 is mounted in the top of the rack. http://www.vintage-computer.com/vcforum/album.php?albumid=2&pictureid=283

Like I said, it's unimpressive, but at least compact. The RK05 is slated to go below the DSD440, then the rack will be full.

Lou
 
Lou - N2MIY said:
Tim,

Well, we have not yet begun to work on it in earnest. I thought I'd get the RA80 going first, which I have, and clear some other projects out. The RK8E is coming up soon though.

Annoyingly, my DSD440 (RX02 work-alike) needs to have the drive heads aligned. (anyone have an extra Shugart SA120 alignment diskette?) I may do that first to make loading the maindecs easier. I am afraid this is the punishment I get for keeping the equipment in the unheated garage. It swings from about 35 to 90F over the course of the year.

Here is a photo of my 8/e with TA8E/TU60 and the DSD440. The TU60 is mounted in the top of the rack. http://www.vintage-computer.com/vcforum/album.php?albumid=2&pictureid=283

Like I said, it's unimpressive, but at least compact. The RK05 is slated to go below the DSD440, then the rack will be full.

Lou
Click to expand...

Looks just fine to me. It's got a pdp-8e in it. What more do you need? :) I wish I
could offer you a rack. I had a DEC short rack for quite some time, but just before
you came to visit I gave it to Jon to start him on his way to having a system. I also
gave him a few RL02s and rails. I'd like to have a PC04 in my 8e. Still hoping to
find one somewhere.
 
EvanK said:
Someday we're going to work out a deal for David to restore ours .....

Fun (and very dorky) video teaser: http://www.youtube.com/user/MidAtlanticRetroComp#p/u/16/J3XrttYVFZU
Click to expand...

I am more familiar with the later 8's than the straight 8. I have an 8i and 8e. The straight 8's are very impressive to see. I have never dealt in trying to restore something with
discrete logic. But I would guess it would be similar to an 8i in cleaning it up. I'd like
to see it working again as I have never seen one running, only ever seen 2 in my lifetime
before this one. Good luck with it.
 
tradde said:
I am more familiar with the later 8's than the straight 8. I have an 8i and 8e. The straight 8's are very impressive to see. I have never dealt in trying to restore something with
discrete logic. But I would guess it would be similar to an 8i in cleaning it up. I'd like
to see it working again as I have never seen one running, only ever seen 2 in my lifetime
before this one. Good luck with it.
Click to expand...

Thanks. Come visit us (and it!) if you're ever in the NYC or Philly area.
 
Lou - N2MIY said:
Evan,

Actually Tim and I did see your straight-8 already at this past VCF. Hopefully we see it running at a future VCF.

Lou
Click to expand...

I had that in my initial reply to Evan. But I hit backspace somehow and lost it. When
retyping it I left out that I had finally gotten to a VCF event. I regretted not going the
year before and meeting Dave G. so I finally went and it was very enjoyable. I only
got to go on Sunday though.
 
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