Yes, it runs Spacewar!

June 2, 2024 9:55 AM

“CuriousMarc” talks to Oscar Vermeulen about his scale replica of the PDP-10, the MIT AI Lab, and the Incompatible Timesharing System.

Marc “CuriousMarc” Verdiell (previously) is a vintage hardware enthusiast. His YouTube videos cover everything from the Macintosh 512K to the Soviet Mechanical Space Nav Computer.

Oscar Vermeulen’s interest in vintage and homebrewed computers led to his designing and selling functional ⅔ scale replicas of PDPs (dubbed PiDPs because a Raspberry Pi runs the emulation software.) You can download the manual (docx) for the PiDP-10.

The actual PiDP-10 software lives on github. It can be run on a recent Raspberry Pi (or most other X86/64 Linux boxes.) No front panel kit is required.

The video mentioned in the video: (Computer History Museum’s) Lyle Bickley explains the PDP-1 (and we play the original Spacewar!)

posted by ChurchHatesTucker (17 comments total)

I should note that although Oscar and Marc consistently refer to the PDP replicas as “⅔ scale replicas” they are, of course, only refering to the front “blinkenlights” panel display. The rest of the cabinet (or room, in the case of the 10) is comfortably emulated on a Raspberry Pi the size of a deck of cards (or credit card in the case of the PiDP-8 with a Pi Zero 2.)
posted by ChurchHatesTucker at 9:56 AM on June 2 [3 favorites]

Saw this the other day and love it. There's just something about the 11 (and related systems) with those beautiful switches in those colors. It's a shame DEC ended up going to the more bland "professional" looking thing and we'd have to wait for SGI and their Indys/O2s etc for such color to come along. Even the cool "gamer" systems is still typically just white, black or grey. Or if a color - all just one color. Though we have more than blinkenlights I guess these days.

Great link!
posted by symbioid at 10:45 AM on June 2 [1 favorite]

Even the cool "gamer" systems is still typically just white, black or grey. Or if a color - all just one color.

It's the mechanical keyboard crowd that is carrying the interesting colorways torch these days.
posted by ChurchHatesTucker at 11:28 AM on June 2 [2 favorites]

I have one of Oscar's early PiDP-8 kits. The production of the newer kits is much better, as the PiDP-8 has some random wooden bits holding it together inside a commodity bamboo box. It runs well, but perhaps a little too fast: the blinkenlights — which use up a vast amount of CPU power modelling the illumination of the incandescent bulbs that the originals used — are barely traceable. It sits behind me in Zoom meetings looking cryptic.
posted by scruss at 11:29 AM on June 2 [4 favorites]

I love Marc's channel, especially because of how varied it is. The videos on the old NASA computers are fascinating, and I enjoyed this recent one where they restored a massive floppy drive.
posted by JZig at 12:52 PM on June 2 [1 favorite]

Nice. Now to find my tapes of the data on spectra of HII regions in barred spiral galaxies. I'm assuming he's also built a replica tape drive.
posted by neuron at 12:54 PM on June 2 [2 favorites]

Nice. Now to find my tapes of the data on spectra of HII regions in barred spiral galaxies. I'm assuming he's also built a replica tape drive.

Marc has restored a couple of old tape drives so it might be possible, but the bigger issue is that old tapes tend to have lost all the bits. I'm part of the team working on Medley Interlisp and I found a box of old tapes that we're sending to a professional recovery service to see if there's anything useable on them.
posted by Runes at 2:59 PM on June 2 [3 favorites]

It's the mechanical keyboard crowd that is carrying the interesting colorways torch these days.

In retrocomputing discussions it's useful to point out that the mechanical keyboard crowd often carries the cutting torch these days too: there remains a fad of ripping keyboards out of old systems and attaching them to modern machines via some kind of interface that converts to USB. These conversions appear not to be used for very long, instead piling up in collectors' stacks for occasional brief amusement. (For day-to-day typing, modern keyboards are often simply more practical.)

I can see the appeal of this pastime, but often a brute keyboardectomy renders the rest of the machine much less useful for preservation or for holistic recreations of how it was used. It's not uncommon for some of these systems to appear for sale once or twice per decade, and the retrocomputing folks like the ones in this video have to mobilise quickly before the "keyboard vampires" catch the scent.

Unfortunately many eBay sellers are aware of the trend, and lots of terminals and computers with detachable keyboards from before ca. 1985 have keyboard and system unit auctioned separately. For a particularly hyped keyswitch mechanism (e.g. IBM beamspring), even integral keyboards aren't safe: the seller may perform their own keyboardectomy so as not to miss a payday.
posted by Chef Flamboyardee at 12:37 AM on June 3 [3 favorites]

I loved the reconstruction process, the replicas, the whole affair, but...well...

Their web site says:

We work based in a Panamanian Free Trade Zone facility, where Makers' designs are produced very cost effectively.
...
These operational efficiencies regarding 'parts in, parcels out' are combined with the Free Trade Zone's zero import/export tariffs. And the payment to Makers is free from any taxation or bureaucracy.

I'll let each individual decide what that means for them specifically, but I think I'll pass on this organisation for now.
posted by rum-soaked space hobo at 2:35 AM on June 3

I've really been enjoying playing with Tiny Tapeout which lets people make real chips for a few $100

Last year I taped out a PDP-8 (something I programmed in college in the mid 70s) it went in TT3 and I got it back just before I went on vacation, now I'm back I'll try and bring it up, if it passes the test vectors I try and boot OS8 on it .....

Tiny Tapeout is accessible to total beginners, not only for those with previous experience
posted by mbo at 3:07 AM on June 3 [2 favorites]

Ooh, mbo, I would be interested in hearing how your TT3 PDP-8 goes. Can we still get the TT3 silicon from somewhere, if it does work?
posted by rum-soaked space hobo at 3:21 AM on June 3

Sadly no, they produce very limited numbers of dies in each run - it also needs a bespoke memory subsystem (I'm using an Arty (FPGA) for that) - lots of multiplexing, mostly because of the tiny number of pins available - the early TT cells are tiny, this was mostly an exercise in being tiny, now days you could probably squeeze a '10 into the 2x8 cells that people are taping out RISCV-32s into

Anyway my PDP8's source is linked to above, people are free to hack on it, mostly it's missing mult/div, it's not complex
posted by mbo at 4:12 AM on June 3

→ a fad of ripping keyboards out of old systems

Yes, a major irritation. The Apple IIc Plus, rare enough on its own because of its very fast CPU, also uses rare keyboard switches. These machines are getting predictably ripped apart by the keebweenies.

→ Panamanian Free Trade Zone

Eww. Eww eww eww no. At least my PiDP-8's old enough to merit a "Not Built by Enslaved Labour" sticker.
posted by scruss at 5:43 AM on June 3 [1 favorite]

If you're interested in small-scale replicas of vintage computing hardware, I absolutely have to mention Trevor Flowers, who produces miniature versions of classic computers, some of which actually work. So you can get a tiny CM-2, a wee TRS-80, or a miniature Memex. There's even a smol floppy organizer for your micro-SD cards. They're currently in process on a 1:3 scale VT100, complete with working tiny keyboard. full disclosure: i have one of the miniature Osborne Ones and it makes me squee every time i look at it
posted by phooky at 10:57 AM on June 3 [4 favorites]

"It's the mechanical keyboard crowd that is carrying the interesting colorways torch these days. -- ChurchHatesTucker

It's funny I didn't even think about that considering I use the old "flashing lights and lit mechanical kb"
I've never ordered custom caps, but now I'm thinking.
There are a lot of beautiful caps, and you might be able to do with some that are "close enough" in color, but.

Wonder if there's a market for PDP inspired caps as a set.
What would a modern PDP inspired Keyboard look like, I wonder (colorwise, obviously I'm not gonna have 105 PDP switches arranged in a keyboard layout LOL).

Tiny Tapeout is so cool I wish I were more a hardware guy, but the universe didn't bless me with electrical smarts. (Evidenced by the time I stuck both wires of an old crystal radio ear piece in the spaces of an electrical socket while listening to the 60 hz hum, somewhere around 9-10 years old.)
posted by symbioid at 11:04 AM on June 4

What would a modern PDP inspired Keyboard look like, I wonder

Rose & Magenta function keys, for sure.

There was a set of "space cadet" keycaps offered a while ago.
posted by ChurchHatesTucker at 11:57 AM on June 4 [1 favorite]

I have a lingering hankering to buy a couple of "KeyBows" and turn them into the toggle switches for a PDP-12 front panel. I figure three of them in a row would be 12 buttons wide...
posted by rum-soaked space hobo at 4:46 AM on June 5