Alex Brown thelastpsion · he/him
  • https://oldbytes.space/@thelastpsion

  • Psion hardware/software hackery, especially SIBO/EPOC16 (Series 3, etc)

    • Psion Community founder
    • Made PsiDrive
    • Slowly rewriting the SIBO C SDK in Object Pascal (yes, really)
    • Co-maintainer of plptools

    Warning

    Will sidequest

  • Joined on 2025年08月17日

Hi! I’m Alex and I have a PDA problem.

In 2018, after 16 years of using various Psion portables, I decided to try my hand at developing hardware and software for my beloved Series 3c to help me with journalling and creative writing.

7 years and repeated sidequests later, I’ve ended up doing a lot of research into the SIBO/EPOC16 platform, and done my best to document it when I can. I’ve also nudged former developers into open sourcing their old Psion apps.

I also "run" the Psion Community, a group of misfits trying to drag Psion’s machines from the 80s and 90s into the 21st century. Check out our Codeberg organisation for a few open source tools and games.

Featured Projects

PsiDrive and libsibo

  • PsiDrive - an RP2350-based USB drive for SIBO SSDs

  • libsibo - the firmware for PsiDrive, currently using the Arduino libraries (to be ported to the RP C/C++ SDK)

plptools

I am one of the co-maintainers of plptools, a *NIX PLP client.

Rewrite of the Psion SIBO C SDK

Psion’s SIBO (16-bit 8086) C SDK has tools that were originally written for DOS. I’ve begun reverse-engineering and rewriting the tools in the SDK in Object Pascal (highly portable and fun to use), creating tools that are drop-in replacements for the original, and run on modern operating systems. So far I have worked on:

  • CTRAN - Psion’s OO C preprocessor

  • ECOBJ - OMF object file processor

At some point in the future I want to write a new C compiler, targeting EPOC16.

A screenshot of KDE Plasma running on Arch Linux. The background window is Kitty running tmux. In the main tmux pane is NeoVim showing some CTRAN-ng source code, written in Object Pascal. In the smaller pane on the right is CTRAN-ng’s help output. In the foreground is a copy of DOSBox Staging, also showing CTRAN-ng’s help output. Both have been compiled with Free Pascal.

About Me

Outside of retrocomputing, I’m your common-or-garden British nerd. I’m a Linux user - mostly Arch, but I dabble with others. I also like a bit of Haiku OS - I meaintain the port of MAME for Haiku.

I used to be a senior computer monkey, specialising in on-prem SME infrastructure (I lament the loss of vSphere). Now I train others to become computer monkeys, for better or worse. As a result, sometimes you’ll see me wrestling with old Cisco ASAs, Ubiquiti APs, or modded kit running OpenWrt.

Generally, I like making things do stuff, especially if it’s stuff that the thing wasn’t originally designed to do.

Photo of a fully constructed PsiDrive 0.0.1, including a Raspberry Pi Pico mounted on top. There is a SIBO solid state disk (SSD) plugged into the 6 SIBO-SP pins. A microUSB cable is plugged into the Pico. To the left of the PsiDrive is 128K Flash Psion SSD.