@stepleton@oldbytes.space

Tom Stepleton @stepleton@oldbytes.space · Jul 26, 2026

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: https://media.ccc.de/v/emf2026-91-1-rsre-flex-reviving-an-innovative

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Tom Stepleton @stepleton@oldbytes.space · Jul 17, 2026

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!

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Tom Stepleton @stepleton@oldbytes.space · May 07, 2026

Replying to @Cdespinosa@mastodon.social

@Cdespinosa@mastodon.social That's why I call C3H8O "the 'propes". "Some 'propes will clean that up." "Hit it with the 'propes." "Smells like the 'propes in here."

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Tom Stepleton @stepleton@oldbytes.space · May 03, 2026

Can't wait to get my hands on one of these. It's been amazing to see Alex at work on this!

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Tom Stepleton @stepleton@oldbytes.space · Apr 14, 2026

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

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Tom Stepleton @stepleton@oldbytes.space · Apr 11, 2026

Replying to @stepleton@oldbytes.space

@skeezicsb It's also a testament to how terribly slow Firefox PDF rendering is... Even reading the schematics with Acrobat on the Pentium-powered logic analyser is a lot faster!

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Tom Stepleton @stepleton@oldbytes.space · Apr 11, 2026

Replying to @stepleton@oldbytes.space

@skeezicsb yes of course 😎 For all the fixes I've had to put in to the EIO board, I wish I'd had it printed much sooner...

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Tom Stepleton @stepleton@oldbytes.space · Apr 11, 2026

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?

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Tom Stepleton @stepleton@oldbytes.space · Feb 22, 2026

Replying to @GypsumFantastic@toottoot.eu

@GypsumFantastic@toottoot.eu Now that looks like training material, and quite a few more than 50 disks. I'll DM you an address. My approach will be to sort them by manufacturer and type and then try them one by one. I'd like to develop some familiarity with the kinds of behaviour to expect from different makes of disk.

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Tom Stepleton @stepleton@oldbytes.space · Feb 22, 2026

Replying to @GypsumFantastic@toottoot.eu

@GypsumFantastic yes, that's just the kind of thing I'm looking for, especially if they are cheaper, lower-quality disks that are harder to recover! But to stress, I'm looking for disks to use for practice as I develop my technique, so while I would do my best, there's a chance that any data sent my way would be lost forever...

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Tom Stepleton @stepleton@oldbytes.space · Feb 22, 2026

Replying to @scunneen@mastodon.social

@scunneen Well, I guess I won't pass that up 🙂 I'll DM you an address...

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Tom Stepleton @stepleton@oldbytes.space · Feb 21, 2026

Replying to @scunneen@mastodon.social

@scunneen I'd feel a little foolish turning away blank 8" disks! But I'm in London and it seems like shipping to the UK could be expensive. How many did you get?

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Tom Stepleton @stepleton@oldbytes.space · Feb 21, 2026

Replying to @moonshinebrigade@musicworld.social

@moonshinebrigade @elfi I'd like to be, and I think I have pretty good odds of being able to do it, but I'm looking for disks to practice on --- so I wouldn't want to try with anything too precious!

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Tom Stepleton @stepleton@oldbytes.space · Feb 21, 2026

Replying to @DosFox@tech.lgbt

@DosFox Sounds like a worthy challenge! I'd like to give them a go, but just remember that my objective is practice (so don't share them if they are valuable to you). Thanks!

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Tom Stepleton @stepleton@oldbytes.space · Feb 21, 2026

Replying to @Mpwg@hachyderm.io

@Mpwg yes, that's the idea! In fact there is a a data recovery effort I'm working towards where I'd like to be at the top of my game.

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Tom Stepleton @stepleton@oldbytes.space · Feb 21, 2026

Replying to @DamonHD@mastodon.social

@DamonHD Absolutely! I'll be making flux recordings in any case, using a Greaseweazle or an Applesauce controller.

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Tom Stepleton @stepleton@oldbytes.space · Feb 21, 2026

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. Therefore I'm looking for loose collections of old floppy disks to practice on. I'm especially interested in working with disks where the binder affixing the media to the donut is starting to fail. I'm in London; will pay shipping; can pick up disks around here as well. Boosts are appreciated!

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Tom Stepleton @stepleton@oldbytes.space · Feb 14, 2026

Replying to @stepleton@oldbytes.space

The double-decker Frankenfuse fits safely into the fuse holder and the little door still shuts! And best of all, it all works! Multiple power-cycles and it hasn't blown yet.

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Tom Stepleton @stepleton@oldbytes.space · Feb 14, 2026

"So it keeps blowing these 1A 250V slow-blow fuses I've got" ... @foundthefault@tech.lgbt@oldbytes.space ... "Well, I've got some, but they're the wrong size"

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Tom Stepleton @stepleton@oldbytes.space · Feb 05, 2026

Replying to @eschaton@mastodon.social

@eschaton I've just built it on Linux (where I needed to define the symbol EFTYPE, but otherwise no trouble). The github page mentions that 1.0 is untested. Upon trying to read some Office System 1.0 Twiggies, it complained: ./lisafs: error opening image '/path/to/LOS1.0i.dc42': Cannot allocate memory The tool works with Lisa OS 2.0 and 3.0 filesystems, as you report.

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Tom Stepleton @stepleton@oldbytes.space · Dec 12, 2025

Replying to @vga256@mastodon.tomodori.net

@vga256 I never dared to wedge the CR123A into my battery holder. Meanwhile, I maintain my common observation that literally nobody has ever seen a yellow Panasonic BR-2/3A battery leak. I've asked repeatedly in multiple settings and nobody claims to have encountered it. Rob Blessin of Black Hole Inc claims to have handled literal thousands of cube and NextStation boards and says he's never seen it either.

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