Last week at #EMFcamp I gave a talk about the nothing-like-it-on-earth RSRE Flex operating system for #PERQ workstations. I'm very happy with how it came out! For a challenge, watch at 2X: media.ccc.de/v/emf2026-91...

RSRE Flex: reviving an innovative, remarkably odd British operating system that almost nobody knows about

1980: Royal Signals and Radar Establishment researchers realise Flex, a mould-breaking, comprehensively alternative vision of computing. ...

media.ccc.de

Saturday 16:30 at #emfcamp Stage B: a talk I've been looking forward to giving for over a year. It's ambitious but if I pull it off I think it'll be a lot of fun. I want it to be a treat for computer history, OS, and programming language buffs, and for everyone else too!

Hello! Next Saturday at 4:30 PM, I'll speak at #EMFcamp Stage B on the obscure, innovative, unusual Flex computing environment for #PERQ workstations. (Demo included!) Fitting everything into a half-hour will be tough: expect fast talking, big gestures, and maybe a bell or gong to mark chapters...

Belated announcement: this weekend I will be at https:// retrofest.uk with my #PERQ 2T2 graphical workstation from 1984, which (after months of troubleshooting, which I promise to describe someday) appears to have been working just now. I've successfully booted:

Ah, the English springtime tradition of cutting out bits of metallised mylar space blanket and taping it over the window panes (In my experience it does help with sunny heat, especially for skylights!)

Please join me in praying that nothing else fails before the show. RetroFest 2026, Swindon, 30-31 May. You *might* see a working PERQ 2T2 there.

EIO board U48 CPU board U134 🎯

Patio. Rhymes with "ratio."

Mr. Escher A. Bug, MSc @ SPX 2026@escherbug.art · 3mo ago

Hey tell me about a word you always pronounce wrong for fun or because of a piece of media that did it, like popato chisps or weclome back or hemborger

45 days until #RetroFest 2026 in Swindon. #PERQ status: - Flaky Z80-based I/O subsystem: sometimes the #Z80 jumps off the tracks and executes nonsense code - Disk boots fail: the microcode attempts to load blocks far beyond the end of the disk Trying today: DIY diagnostic microcode

POV: #PERQ hardware debugging, as usual. The #Z80 (serving as an I/O coprocessor) is behaving strangely: fetching instruction bytes without toggling the M1 pin, jumping to random locations at around 47uS after coming out of reset; what's going on here? RetroFest in six weeks or so...

Developing technique for "disk baking". The box is a filament dryer for 3-D printing, and the disk "bakes" inside at 55 °C for six hours in an attempt to stabilise the degraded binder that holds the magnetic oxide to the PET substrate.

I struggled with vi on the Torch. There's only one thing to do. Compile uemacs on the Torch. In the process of modifying the code to K&R formats I've started to like vi, rendering this task pointless. But now I've started I need to to see if uemacs will work. Why do I do these things to myself?

You want: a regular #Ethernet MAU to plug into an AUI port You have: a MAU that only works with Apple's weird AAUI port No problem! Here's an adaptor: codeberg.org/stepleton/aa...

This is the manual for the Elliott 803 library subroutine D2. It was implementing this sorting algorithm in 803 machine code that lead to Tony Hoare suggesting to his boss that he had a better algorithm, which turned out to be quicksort.

@adriansdigitalbasement.com I have the same Astec AT PSU as you. Mine has a power-on voltage pulse so high that it immediately shuts itself down. But if you temporarily disable the voltage protection by tampering with the optoisolator, it regulates itself quite well once it has got started.

Do you have 5.25" and 8" floppy disks that are spare, low-quality, degrading, or just generally in bad shape? I'd like to take my floppy disk data recovery game to the next level. I have equipment, but there's no substitute for experience.

Rudimentary bootloader @adriansdigitalbasement.com ? I think it's fairly sophisticated! 😀 codeberg.org/stepleton/ca... All hand-coded 68k asm down to the text display (the ROM only has routines for UPPERCASE). Congrats on progress, it's been a blast to watch. PS: hit backspace during screensaver

PSA for Jan 1: www.fvap.gov remains a fine way for US citizens living outside of the US to request an absentee ballot without winding up on somebody's mailing list.

Americans can vote. Wherever they are.

Ensuring Service members, their eligible family members and overseas citizens can vote -- from anywhere in the world.

fvap.gov

How I got an Apple Lisa to play audio samples: lisalist2.com/index.php/to... An extension of this technique: www.youtube.com/watch?v=3SlR... using a method also speculated by Adam Podstawczyński forgottencomputer.com/retro/sound/...

Some disk images for Lisa 1 and Lisa 2/5 systems

Some disk images for Lisa 1 and Lisa 2/5 systems

lisalist2.com

I'm recruiting a PhD student for autumn 2026 on a project on accessibility in musical instrument design, in partnership with disability arts charities OHMI and Drake Music. Application deadline 15 February 2026. More info and contact details: liss-dtp.ac.uk/project/inst...

Has anyone ever heard of a (UK?) journal called University Computing? Know where I could find archives? Long shot, but this paper could contain info that helps us open-source a remarkable operating system developed by the UK MoD in the 1970s and 1980s. Boosts appreciated!

Oh dear, could this be in regard to oldbytes.space/@stepleton/1...? I'd never say lithiums don't leak (I've seen enough Maxells and Tadirans to know better), but I still quest to find a BR-2/3A cell that has. It's the only exception, so I ask out of disbelief. Or was a better world always possible?

Nanoraptor@nanoraptor.danamania.com · 8mo ago

Half the time I post similar below, someone pops up with "except lithium batteries, they don't leak" because SOME lithium batteries are advertised as having never been known to leak. If you can identify those good luck to you, otherwise get the batteries out of your old gear!

@breakintoprogram.co.uk so the problem with my Spectrum+ was the Z80, it turns out. The address bus was stone dead, +0V on all sixteen lines. Subbing in the CPU from my Jupiter Ace got it going; a replacement is now on order. Thanks for the chat on Sunday!

Just in time for #PERQtober ! An adapter to replace your missing or broken #PERQ T2 landscape monitor with a VGA display: codeberg.org/stepleton/pe... Thanks to @skeezicsb@oldbytes.space for early advice.

The Olivetti Programma P203 (1967) uses a circuit construction technique known as "transistor jail" (or "cordwood" [1]. Seen at [2].) [1] en.wikipedia.org/wiki/Printed... [2] www.thecomputerchurch.org

Wheeling Airglow (en.wikipedia.org/wiki/Airglow... ) out to the runway at the British Human Powered Flying Club's 2025 Icarus Cup event, Lasham Airfield, Hampshire.

Happy Pride #rc2014

#Smalltalk -80 on #PERQ --- Mario Wolczko's implementation (www.wolczko.com/st80/) running with maybe some gremlins still to sort out.

#PERQ PNX 5.03 manual pages at mg-1.uk/pnxman/pnxma... . The most interesting ones don't render very well with my hacked copy of a roff-in-JS "typesetter", but some interesting nuggets are there to reward persistence.

Grab your ear defenders, it's time to see the exciting features of 1986's PNX 5.03, the Unix for the #PERQ 2 workstation! Skip to 2:10 to bypass booting and go straight to the non-X11 graphics action! www.youtube.com/watch?v=TZRo...

PNX 5.03 reboot and demonstration on a PERQ 2T2

YouTube video by stepleton

youtube.com