PiDP-8/I Software
I am a primary committer for the software that runs on Oscar Vermeuen's 1/3 scale PDP-8/i replica with an embedded Raspbery Pi. I've been involved for a number of years and learned a lot!
My involvement began with an interest in stewardship of PDP-8 OS/8 sources. I then built tools based on python expect to script the creation of bespoke bootable OS images from source. I gave a talk on this work at the 2026 Vintage Computer Festival East. Slides from my talk: PDP8-Talk-VCF-East-2026.pptx
I re-targeted Ian Schofield's PDP-8 C compiler from a moribund smallc implementation to one that seemed to have active upstream support..
I integeated an updated handler for gpio so that we could support Pi4 and Pi5 hardware.
To enable U/W FOCAL built from source to run on museum-piece hardware lacking an Extended Arithmentic Element (EAE), I wrote an EAE Emulator module with the aid of AI. The original non-EAE floating point module sources had been lost. I learned that chatGPT can't code, and that claude.ai does good coding, but neither of them are very good at debugging. "Teach me how top do this," rather than, "Do this," seems to work better.
I did the final integration, test, and benchmark validation of the "Cycle Accurate" amendments to the PDP8 SIMH emulation. This enabled Singe Step operation, and displays of Major States within instructions. I have begun the process of learning how to maybe get it accepted upstream.
I rewrote a draft of a software change to enable correct operation when mounting the deposit switch upside-down. Long Story: DEC mounted the Deposit switch upside down on all hardware for contrast to clearly warn, "You're writing to memory! Be careful! Oscar's Kit mounted it like the other momentary contact switches sacrificing historical accuracy, for less confusion from people seeing a PDP-8 front panel for the first time. Die hards would flip the switch and do a trace cut and bodge wire job. Now you can just mount the switch either way.
I took over release creation, and pushed the Tax Day 2026 release across the finish line. This included replacing the bosi release creation script with utilization of the new rpi-image-gen platform.
PDP8-Alive
A proof of concept for a cooperative that collects, restores, and curates documentation and code for the PDP-8 originally developed by Digital Equipment Corporation.
The first Proof of Concept was a retrospective on ADVENT the PDP-8 port of the RT-11 FORTRAN implementation of "The Colossal Cave Adventure" game. We fixed a bug in the original version, tracked several intermediate versions, and publish source of the current latest and greatest version.
Currently looking for more people who would agree to log their projects here.
AUIS Revival
Bring the Andrew User Interface System back to life on modern POSIX platforms. I've made extensive use of claude.ai, having it do pretty much all the work.
Did an assessment of what might be needed to do a modern port.
Got ez and help running at all under XQartz on MacOS, and the decided on further objectives.
Got messages and amsdemo working, and decided to implement support for IMAP. Basic IMAP support is working, but you have to run an imapsync tool to sync up. A follow-on action will be to get messages more gracefully integrated with IMAP.
Decided that modernizing to ANSI C would eliminate many subtle bugs. That turns out to be a big project hoovering up several weeks worth of claude.ai Pro weekly resources. As of 3 August 2026, this work is 3/4 done.
Many old bugs were found and fixed.
The biggest source of problems: int != long != 32 bits.
The work is extensively documented but in AI-prose. After the codebase stablizes a bit more I'll make an editorial pass through.
Last updated: 31 July 2026