Back in the early '80s I built a kit computer (Compukit UK101), a 6502 based machine with 4K of RAM and BASIC in ROM.

I took the circuit for the UHF output and made my own 6809 based system initially with 4K of RAM and a simple IO board that talked to a 7 segment 8 digit calculator display.

That machine grew to four double Euro sized breadboard with 64K of dynamic RAM, a simple video controller based on the 6545 chip and a floppy disk board based on Western Digital chips.

All done by contacting manufacturers by post and asking for datasheets as a student.

I ran a commercial OS called FLEX/09 (much like CP/M). I had a language called PL/9, a one pass 6809 compiler that was C like but much simpler. Barely any runtime, squeezed to fit into 48K of RAM - an editor and compiler. I wrote my floppy disk formatter with it.

It all died when the wire wrapped wires turned black and the system stopped booting. By then I’d moved onto BBC machines - Electron, Master and Archimedes (ARM based). Eventually I bought a 486-DX2 50MHz - a machine I still have but no idea if it will still even switch on.

Having a hardware background got me a job working for an audio company doing device drivers and eventually a job in audio working for Codemasters, my first games company.