More retro-computing

I ventured into the past again, this time by reviving an old ZX81 computer. The short project included expanding the original memory to 16k and to correctly output video from the old dinosaur.

You can read about the adventure and download the design files in case you want to replicate my work from here.


Well, that’s a mouth-full. It stands for ‘Vintage Computer Festival, Pacific North-West‘. It’s happening this weekend, and I’m presenting the Cray work I’ve been doing. Which reminded me that I should also update this page with direct links to all the random babbling I’ve done about this project over the years.

First off, all the articles about the Cray XMP and COS restoration work:

  1. Prelude
  2. A New Hope
  3. The Hunt for the Red Bootcode
  4. The Return of the Cray
  5. The Matrix
  6. First update
  7. Needle in the Hay-stack
  8. A Brave New World
  9. Multiple Platforms
  10. Jobs
  11. Parallels
  12. Turbo

The second series is about the newer, J90 (and YMP-el) simulation work, running UNICOS:

  1. A Bridge too Far
  2. That Obscure Object of Desire
  3. Exploring the CD
  4. A New Simulator, part 1
  5. A New Simulator, part 2
  6. A New Simulator, part 3
  7. The UNICOS file-system
  8. Oldies but goodies
  9. A debug session
  10. To SSH and beyond

You can download the latest version of the simulator (including source code).

However if you’ve read all the above (as I’m sure you just did), you’ll know that the download page doesn’t actually contain functional UNICOS images: I don’t have the rights to distribute them. Because of that, I’ve put the simulator on-line, so – while you still can’t run it yourself – you can experience the full glory of a late 20th century supercomputer.

To anyone coming here because they ran into my exhibit on the VCF PNW, thank you again! For everyone else, still thank you for dropping by my page and enjoy!

The Return of the Cray files

Good news everyone!

A very nice gentlemen – who decided to remain anonymous – contacted Chris and me, saying he has some X-MP tapes we might be interested in. As it turned out he has an absolute treasure chest of material, in fact much more than ‘just’ a collection of X-MP tapes.

This gave me a reason to re-start my work on the Cray simulator project, in fact I’ve decided to start a new series. If you’re interested, check it out here.