PDP-8 replica kit: the PiDP-8

Name: PDP-8 replica kit: the PiDP-8
SKU: 20893
Price: 210.00 USD
Availability: OutOfStock
Rating: 4.88 (8 reviews)

(8 Reviews)

A faithful scale 6:10 replica of the PDP-8/I, fully compatible.

Designed by Obsolescence Guaranteed in Switzerland

2020-07-29T17:10:37.431Z-nice matte..jpeg

$210.00

Out of Stock

Sold out since Sep 09, 2024

A faithful scale 6:10 replica of the PDP-8/I, fully compatible.

What is it? The PiDP-8 is a modern replica of the PDP-8/I. Basic soldering skills are required to build the kit. Or you can buy it assembled & tested. Everyone wanted a PDP-8 minicomputer. Well, in 1…

What is it?

The PiDP-8 is a modern replica of the PDP-8/I. Basic soldering skills are required to build the kit. Or you can buy it assembled & tested.

Everyone wanted a PDP-8 minicomputer. Well, in 1968. Blinkenlights, you see. Digital Equipment scored a major hit with their small 12-bit minicomputer. It was used for everything, from controlling toll booths to launching rockets. It might have been intended as the Arduino-equivalent of its time, but it was also the birthplace of personal computing, with hard disks, operating systems and comfortable software.

My goal with this project: make a faithful, low-cost replica of the PDP-8/I (1968). Operated through a Blinkenlights front panel, it should bring back the user experience from the past. Replicating all stages in its development: from 1968 to 1979, from teletype & paper tape all the way through to hard disks and multi-user systems.

Why did you make it?

In 2015, I made a replica of the PDP-8 for myself, as the Real Thing was above budget. Also, the real machine is hard to obtain, hard to maintain and just a little too big for the living room. But that is where I wanted it to live.

The amazing thing of a PDP-8 is what it can do despite its simplicity. A CPU with 8 instructions, no stack pointer and 32K Words of memory - yet it serves 6 users smoothly if you insist. To my surprise, I ended up making over 2500 PiDP-8 kits so far. A lively community has sprung up on Google Groups. Almost all of the original software has been preserved, and a rich selection comes ready to boot. From spacewar (the first video game ever, now played on a simulated vector display) to multi-user TSS/8, it is all there. And new software appears on a regular basis. Things nobody would have thought possible on the humble PDP-8: C compiler, emacs clone, a new Forth, Lisp... but it's OK to just enjoy the original Adventure too.

What makes it special?

You could look at this as a smallish PDP-8, built with modern parts. Or alternatively, and equally valid, as a fancy front panel case for a Raspberry Pi. Because inside is simply a Raspberry Pi running the excellent simh emulator. (Note you have to provide the Pi yourself, it is not included in the kit). It will happily run any other Pi applications concurrently with the PDP-8, so if you follow the intention of placing it in the living room, it can do more than just be pretty and wait for PDP-8 logins. Use it concurrently as a media or file server - whatever you want to use a Pi for.

The PiDP-8 can be used with a proper vintage serial terminal (or Teletype!), but you can also log in over wifi from your laptop. The PDP-8 inside won't know the difference. Of course, you don't need a terminal: Real Men program on the front panel... but soon enough you'll want go back to the comfort of the OS/8 operating system. Front panels are nice just for debugging, not programming.

A few notes: - this is the 2024 version of the kit. It's no longer hard to solder in the switches, they come with their own stable brackets now. Also, I was finally able to produce a matte (non-glossy) front panel acrylic, just like the original machine had. Trivial as that might sound, matte acrylic that does not blur the lettering was hard to find. A local museum helped me out on this with special museum-grade acrylic (thank you!).

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Review Breakdown

Average Ratings

Product: (5.00)

Documentation: (4.75)

Shipping: (4.88)

Communication: (4.88)

Nicholas | Oct. 27, 2023

Quality product!

The PiDP-8 kit could not be easier to build if you ask me. It took me two nights, but only because I had to take breaks to be a good husband and father. Other than that you can get it done in a few hours if you have experience with building kits like this. If you don't, it won't take you that long at all.

I even took my time to place and solder each part individually rather than my usual approach of placing multiple parts, securing them, and then soldering them all at once.

The software setup was easy as well. Indeed I had the simulator up and running before I started building the kit. Now it's all together and running and it's so much fun for an old guy like me to be able to flip switches to select a memory address and deposit a value, or watch the lights to be able to know what the machine is doing, or to stop it with a switch and single-step through the instructions the same way. Thanks, Oscar, for making this. In the next couple of months, I intend to order the PiDP11/70.

Jacob | Dec. 20, 2022

Beautiful craftsmanship, excellent soldering kit

While it's true you can get 80% of the experience by using SIMH on a bare Raspberry Pi, nothing quite matches the look and feel of snapping switches and watching the blinkenlights fade in and out. The experience of programming a PDP-8 is austere and minimalist. This review is for the hardware and its documentation. The case is wooden, and thus very configurable to meet your needs. The main PCB is well-marked and sensibly laid out. The instruction sequence is well documented. I "boldly" soldered the single buffer IC directly to the board rather than using a socket. I have one teeny-tiny complaint: I wish there were an insulator (e.g. plastic, wood, paperboard) included, to put between the Raspberry Pi and the back of the PCB, as the instructions mention that the USB and Ethernet shields on the Pi 3/4 will short out some of the LED leads if it touches them. But creating one myself was as easy as cutting up an empty paperboard cereal box with some scissors. It was a little fiddly to get the screws in place to hold the insulator and Raspberry Pi to the back of the main PCB.

My advice: Be very careful handling and installing front panel, as its rear scratches very easily, and these scratches become transparent. Also, don't attach any extra components "just in case," like a spare USB drive key, without first testing the whole system before you mount it all in the case. Otherwise you'll find your system no longer boots, and you have to either cut a big hole in the back of the case, or unscrew everything to get it working again!

Heinz-Bernd | Sept. 15, 2021

Amazing kit

I can fully recommend this kit. It is easy to build even for beginners, but you need to set aside a few hours for the task (> 400 solder joins, e.g. per switch there are 9 joins you'll have to solder (1 diode, 3 electrical switch contacts, 4 pins for mechanical support).

Half of the credit must go to the people at tangentsoft who contributed a lot of of the software needed to link the panel to the simh simulator. An almost insane amount of effort must have been spent to make the LEDs appear more like real light bulbs (as in the original PDP-8) (fading effects etc).

The finished kit is very pleasant to look at, but the main fun and amazement to me was discovering what amazing things people in the 60s and early 70s could do with this little computing power, and this is best experienced hands-on of course. This is great for your yearly Python-Detox. ;-) .

P.S.: Contrary to what I wrote in my PiDP-11 review (not editable now), you really should assume that the front panel side is indeed covered with a protective foil that you need to peel off for best results: on the new matte panel the protective foil is transparent, rather thin and difficult to see when your eyes are failing :-)

James | Sept. 13, 2021

Smaller replica of the first compuiter I learned to use

Good design with excellent printed circuit boards. It would be fun even if it did nothing but blink the lights, but the software runs on it better than in 1969.
Two suggestions: 1) I really miss the key-switch panel. I would love to have it, and found some miniature "look alike" key switches that would look great there.
2) If there is ever a time to make more front panels, please make the LED masks square instead of round.
Thanks for a great project!

Tom | June 29, 2021

a fantastic kit, well-crafted, fun to assemble

I am very happy with the kit so far, although I have not fully assembled it yet. Assembling and soldering were fun. The documentation is helpful and accurate.

I highly recommend this kit to all legacy system enthusiasts. :-)

It's not a cheap kit in terms of money and quality. If you can afford it go for it. Oscar prepared a fantastic kit, well suited for your living room.

James | June 29, 2021

Superb little project

Very nice little project - the PCB and case are nice quality and components go on easily (I always use flux anyway), whilst the switches and front-panel are perfect.

Since I'm using mind as a wall-mounted NAS, it was nice to find space in the box enough for a USB SSD and a PoE power splitter. I drilled some ventilation holes as well.

Mogens | June 9, 2021

High Quality Retro-Computing Experience

This is an amazing, awesome kit! All components are high quality. The building instructions found online are very clear, and it was easy to solder and assemble. Take your time to ensure that the alignment of the front panel switches is right (I don’t think it was too hard, just don’t rush it).

With the PiDP-8 kit you can really get the feel for what it was like to program in the 60’s and 70’s. And it is very satisfying to watch the blinkenlights accompanying your work, when you walk through the bootstrap procedures, using the front panel switches. Note that there are nice shortcuts in the PiDP-8, if you don’t want to toggle in everything every time you want to use the system! Running DEC OS/8 from disk, you probably won’t use the front panel switches very often.

The PDP-8 system demonstrates the huge progress in software for the computer, from front panel / paper tape programming in PAL assembler, to quite advanced operating systems (even multi-user), and compilers and interpreters for several programming languages. All of which can be used and run on the PiDP-8 kit. I was quite astonished to find out how much of the old DEC software and documentation is easily available on the web.

The PDP-8 was an impressive piece of hardware and software engineering, solving serious real-world problems for business and science.

Very few of us will get hands on a physical PDP-8/I today, I believe the PiDP-8 is as close as it gets. Highly recommended.

Takumi | Nov. 2, 2020

Really excellent !!

This is really the one of the seller’s masterpieces. It isn’t a hobby item but one of historical monuments. For almost senior computer users, the original PDP-8 must have been a favorite machine even in the present days.

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$210.00