What is it?

The PDP-10 was DEC's 1968 mainframe that became the ultimate hacker playground at the MIT AI Lab. The PiDP-10 is a modern replica, in the same line as my PiDP-11 and PiDP-8 kits. Basic soldering skills are required to build the kit. Or yo can choose the Assembled & Tested option. In both cases, you will need to insert your own Raspberry Pi 4 or 5, which runs the simulation behind the scenes! The Pi is not included in the kit.

Introduced in 1968, the Ten brought DEC into the world of mainframe-class machines. The fact that it was designed for real-time multiprocessing set it apart from any other mainframe: this was the supercomputer that you used interactively on a terminal. No batch processing with punch cards.

Although DEC supplied its own TOPS-10 operating system, the PDP-10 achieved a mythical status because it was the breeding ground for the early Hacker Culture at MIT, made famous by Levy’s book Hackers.

The mythical Artifical Intelligence Lab

At MIT’s Artifical Intelligence Lab, the PDP-10 was the heart of a large array of connected hardware, and its ITS operating system became a playground for computer scientists and hackers alike. MACLISP, emacs, the earliest AI demos, they were born on the 10, running ITS.

ITS was an operating system so esoteric that the debugger doubled as the command line, and although massively multi-user, connected to the early internet, open for all – it had no password or security. Anyone anywhere could run a game of multi-user Mazewar on it – or crash the whole system. Which nobody seemed to do as it was just too easy to be cool.

What makes it special?

The PiDP-10 is just the physical form of a much bigger project: the ITS Reconstruction Project. Computer history aficionados went to extraordinary lengths to fully restore the extremely rich software collection running on the ITS operating system. You should read about it here. It's about backing up 40 year old magnetic tapes after baking them in an oven, recovering bits, decompiling binaries, hunting source code and recompiling it all. And reconstructing not only the PDP-10, but the dozens of peripherals connected to it. Including a PDP-6, two PDP-11s, and about half a dozen of vintage terminal types.

CuriousMarc made a very nice Youtube episode about the PiDP-10, you can watch it here: https://youtu.be/E0Pp63gsdZI?t=643.

Here is a picture of the simulated hardware collection contained in the PiDP-10:

The end result is that when you boot up the PiDP-10, you find yourself right back in the historical computer lab of MIT, circa 1978. You can find source code and binaries in the directories of famous ITS hackers like Richard Greenblatt and Richard Stallman. The hard disk is full with a decade's worth of historical firsts in software, plus tons of fun, games and graphics demos. The original life, for one, in high-res graphics displayed on a 1024*1024 radar tube.

This is the only mainframe ever that was used for fun - the software to play with on its disks rivals the things available on many home computers that came out 20 years later. But here, you see the First of everything. The first 3D shooter (Mazewar), the first emacs editor, the (alright) second version of Spacewar. Lisp, C, Fortran, Scheme - dozens of languages. And the first-ever AI that lived in a graphical 3D world: Shrdlu, recently reconstructed again in interactive form.

Please see my PiDP-10 web page for lots of software information: enter link description here

Here is a screen shot showing some of the terminals and graphics displays simulated on the Pi's dual monitors. It is a massively multi-user machine, of course. But note that the laptop also acts as a simulated terminal - you can log in remotely and have a pretty authentic experience with VT-50, Knight TV, VT-100 or half a dozen other terminal simulators running on a Windows or Linux computer. You can even play Maze War on the PiDP-10 over the internet with multiple users - it is the first multiplayer FPS after all :-)

Why do you need one?

Well, need? But this is the only fun mainframe to play with. Also, dozens of people worked on this project to make sure that the history of ITS and the PDP-10 is not lost. We wanted to give people the possibility of a hands-on experience of it, not just read about it. It is the ultimate Hacker's Machine after all :-) You might want to read through the manual, which contains a step-by-step tour of how to use the system - for 21st century people, using ITS is not all that hard anymore!

More information

• This is a large kit - 54cm wide, 120 LEDs, 74 switches. But it is easy to build, all through-hole parts and only three chips. The software distribution contains a test program to verify it all works, and there is not only me but also two other enthusiasts that will give you lots of support when you hit a problem. We also set up a spare parts service, just-in-case :-). Just contact j.leon@ceds.dev and he will connect one of us to help you out. Make sure to read the Building Instructions: Building the PiDP-10

• Why is it so expensive? It is not - we went for perfection with this replica. Just for the injection mold for the case alone we had to scrape together $70,000. Add 74 custom replica switches, an acrylic front panel and two 54cm wide PCBs, and hopefully you will see that this was a true passion project for a lot of us involved in the project, and those costs have to be spread out over the 1,000 kits that we have parts for to make. See the development blog here.

• You can try the software without actually having the hardware! A Naked Raspberry Pi will run everything just fine, it's only that you are Blinkenless (no Blinkenlights) and you'll have to manually boot the PDP-10. It's all explained in the manual (PDF).