The Last Psion | Alex

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

🔸 Made #PsiDrive, a USB drive for Psion SSDs using #RP2350
🔸 Slowly rewriting the SIBO SDK in #ObjectPascal #FreePascal (yes, really)
🔸 Co-maintainer of #plptools

⚠️ WARNING: WILL SIDEQUEST ⚠️
#HaikuOS, #Linux, #BSD, #MAME, #NeoVim, #compilers

Have old Psion source code (#OPL, C, C++, asm), docs or schematics? Please get in touch!

#RetroComputing #permacomputing #RightToRepair #OfflineFirst #luddite #CodeIsArt

Homepage: https://thelastpsion.com
Codeberg: https://codeberg.org/thelastpsion
Psion Community: https://psion.community
Ko-Fi: https://ko-fi.com/thelastpsion

Public Key

npub1h4llguy88kl5dqvk28p48f6ccfmfs9vqc2v4t7av9wgz06dqvausl5g8cc

NIP-05 Address

[email protected]

Profile Code

nprofile1qqst6ll5wzrnm06xsxt9rs6n5avvya5czkqv9x24lwkzhyp8axsxw7gprpmhxue69uhhyetvv9ujumt0d4hhxarj9ecxjmntcj2yjl

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relay.momostr.pink

Author Public Key

npub1h4llguy88kl5dqvk28p48f6ccfmfs9vqc2v4t7av9wgz06dqvausl5g8cc

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Published at

2026-09-22T15:14:40Z

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Last Notes

2026-08-01 19:15:47 GMT

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*Very* relatable. I think I'm about 7 sidequests deep now.

2026-08-01 19:06:01 GMT

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Yep! I completely dismantle the unit and then put some on the front and back of each hinge. But I think you could do one side, let it set, unscrew the battery bar and then do the other side.
Honestly, @npub10a0…ry2t has taken this to a whole new level. I think it's worth bringing him into the conversation.

2026-08-01 18:41:01 GMT

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I've started to preemptively reinforce the hinges on my most used machines rather than wait for them to break. It's worked well on my "daily driver" 3mx - had it for a few years now and it's still going strong.

2026-07-31 14:53:50 GMT

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Interesting to see the parts Martin Roberts used! I used the little sister of the 74HC125 for the CLK line, but used a separate bidirectional buffer for DATA.
https://assets.oldbytes.space/assets.oldbytes.space/media_attachments/files/117/015/119/545/058/651/original/587237eb3cf66721.png
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2026-07-31 14:43:31 GMT

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Well, here's the project itself in Issue 7.
https://archive.org/details/palmtop-issue-07/page/n21/mode/2up
But reading this now, it could be that the driver source was never released and the compiled version only available from Palmtop themselves.

2026-07-31 14:37:06 GMT

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For your 3a, I recommend you call a friend of the Psion Community. Dr J B Weld. 😉
https://assets.oldbytes.space/assets.oldbytes.space/media_attachments/files/117/015/090/401/978/726/original/8e4bebd22ee54ca2.png

2026-07-30 13:10:46 GMT

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Thanks! Yes, I've come across it before.
From memory, the build was spread between two issues of Palmtop - one had details of the software, the other the hardware. At the time I remember only being able to find one of the issues.
But yeah, it was one of the inspirations for the PsiDrive, even if at the time I didn't have all the info!

2026-07-23 20:44:03 GMT

Question for #blind and #visuallyimpaired people who use the command line or terminal.
Does coloured output in CLI apps help or hinder you?
I'm thinking about #screenreader users, people who use magnification, etc.

2026-06-16 19:42:56 GMT

As part of $dayjob, I'm trying to think of five classic 8-bit or 16-bit computers that we could get hold of for educational purposes.
Yes, this really is for my day job. I can't believe it either.
Budget is the only issue. At the moment I can't justify spending more than £100 per machine. Even that is going to be a stretch. I realise how tough this is going to be, but I want to see how close we can get.
I want to avoid consoles if I can help it.<li>ZX Spectrum</li><li>C64</li><li>Amiga 500</li><li>BBC Micro or Electron</li><li>"Early" PC - somewhere between 8086 and 386.</li>
If you have any suggestions for swap-outs, then let me know.
#retrocomputing

2026-04-29 19:46:47 GMT

One of the best AGENTS.md files I've seen so far.
https://assets.oldbytes.space/assets.oldbytes.space/media_attachments/files/116/489/714/574/529/689/original/01da083cedc042f6.png

2026-04-14 14:31:14 GMT

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Thank you!

2026-04-12 06:43:22 GMT

One of my many sidequests is to try to get #NetBSD running on one of my #Psion Series 5mx machines. But I have a few issues/thoughts:<li>I'm struggling to find instructions on how to do this. (Can you help, <a href="https://mastodon.sdf.org/@netbsd" class="u-url mention" rel="nofollow noopener" target="_blank">@netbsd</a> ?)</li><li>Because I can't find any instructions (granted, I was very tired when I tried last night), I'm a little worried that no one has tried this for quite some time.</li><li>Both of my 5mx units and my working S5 are refusing to read any of my seven Compact Flash cards. Including the one that the netBook uses to boot. I have no idea how to fix that, and I don't really want to buy another 5mx as they ain't cheap.</li><li>The winning 5mx will get a RAM upgrade to 32MB. (Yes, that's doable.)</li>
If I can get something working, then that will encourage others in the #PsionCommunity to try. So we might actually get people running a modern OS on Series 5 machines. Also, as there are a good number of programmers in that community, we might get more eyes on the code.
Finally, if that all works out, then it might be possible to get it running on the (currently unsupported) netBook, too.
#Psion5mx #retrocomputing

2026-03-28 23:53:10 GMT

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Definitely didn't go straight to eBay to look at prices. Nope.

2026-01-13 11:40:49 GMT

Anyone have suggestions for YouTube channels where people are creating cool new stuff for old computers?
With notable exceptions, I'm less into "here's an $OldMachine, how cool!" and want more "here's a new thing I made for $OldMachine that makes it really useful or usable today."
**EDIT:** By the way, this can be hardware or software. New storage devices, expansion cards, network adapters and sound cards are just as interesting to me as new SDKs, new compilers that target old platforms, weird ports, and ancient driver mods.
#RetroComputing

2025-12-26 08:13:33 GMT

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If you're interested, 3mx units come up on eBay every so often for £60-£100. Classic S3 and 3a units are a lot more common, though, and are closer to £35 - cheaper if you're happy to fix the hinges yourself.
Alternatively, MAME emulates EPOC16 machines almost perfectly.
If you're OK with Discord, we've got a friendly little community that can help to get you going, including with connecting EPOC16 machines up to modern OSes.

2025-12-25 10:13:27 GMT

How about a little #Psion gaming for the holiday season! @npub1wef…l2we has written a brand new game for EPOC16, entirely in OPL. It's designed for the original Series 3, but I've got it running on my 3mx. The added EL backlight gives it an ethereal feeling to the play.
Get your copy here: https://cyningstan.itch.io/dragonfell-psion-3
#RetroComputing #RetroGaming
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2025-12-23 20:25:15 GMT

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I wonder if @npub1fh7…ee83 would allow this license?

2025-11-14 20:18:44 GMT

People who self-host (anything, not just Mastodon). Are you running services at your house? If so, are you hiding them behind a VPS that tunnels to your home's IP?
CC @npub1huw…c5x7 , because you're the first person I thought of that would be able to answer.
#selfhosting

2025-07-07 17:48:25 GMT

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Not yet! But MAME has very good Series 3(a/c/mx) emulation, so I guess porting that would be possible.

2025-05-10 08:14:34 GMT

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The #Casio chips are interesting.
https://assets.oldbytes.space/assets.oldbytes.space/media_attachments/files/114/482/522/252/052/775/original/ed24294ddbbc6c98.jpg

2025-05-10 08:07:53 GMT

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It's times like these when I wish I owned a bench power supply.

2025-05-10 08:02:36 GMT

Managed to work out how to get into this #Tandy Z-PDA "Zoomer". I haven't found any photos of the insides of this thing online yet.
Unfortunately this one seems to have had some hidden battery leakage, but it seems to be restricted to the speaker and wires for the battery. Everything else looks in good condition.
It can take an external PSU, but I can't find any details on it (voltage, polarity).
Also, it runs #GEOS.
#retrocomputing #pda
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2025-04-25 17:12:53 GMT

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That's really sad. I strongly considered Fosstodon when I first joined Mastodon. I hope you find a new home soon and can do something practical with your posts.

2025-04-01 13:36:31 GMT

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You don't *think* you have been cloned? So there's a chance that you have been without your knowledge?

2025-03-08 08:41:43 GMT

Quick question: Who here is into #retrocomputing more than #retrogaming?
I get why retro gaming is a bigger community, but I want to hear from the people who are into the non-gaming side of vintage computing!

2025-01-10 13:30:41 GMT

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It takes about 3 hours to compile #MAME on my dedicated #HaikuOS build box, a Xeon-upgraded Lenovo M93p Tiny. It's always a tense three hours.

2025-01-10 13:22:52 GMT

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Success! #MAME #HaikuOS #Psion
https://assets.oldbytes.space/assets.oldbytes.space/media_attachments/files/113/804/264/952/787/665/original/bdbf47f1e3fcc9a6.png

2025-01-10 09:17:57 GMT

Finally got around to fixing the patch for #MAME on #HaikuOS. Took about 2 minutes. 🤦
So, to refresh everyone's memory, this is:<li><a href="https://oldbytes.space/tags/MAME" class="mention hashtag" rel="tag">#MAME</a> 0.273, compiling on and for...</li><li><a href="https://oldbytes.space/tags/HaikuOS" class="mention hashtag" rel="tag">#HaikuOS</a> R1B5, running on a...</li><li>Lenovo M93p Tiny with a Xeon E3-1275L V3 upgrade and 16 GB RAM, via...</li><li><a href="https://oldbytes.space/tags/tmux" class="mention hashtag" rel="tag">#tmux</a> over SSH, viewed from...</li><li>Konsole on <a href="https://oldbytes.space/tags/KDEPlasma" class="mention hashtag" rel="tag">#KDEPlasma</a> 6.2.5, running on...</li><li><a href="https://oldbytes.space/tags/ArchLinux" class="mention hashtag" rel="tag">#ArchLinux</a> (btw)</li>
https://assets.oldbytes.space/assets.oldbytes.space/media_attachments/files/113/803/282/075/387/840/original/87e4e54755e3187a.png

2024-12-11 20:01:37 GMT

Tiny bit of #retrocomputing for me today, although not as retro as normal. Also, more #retrogaming than normal!
I invested a whole £16 in an IPS screen for my #PSP1000. It's a big improvement over the original. It's still a little ghosty, but nowhere near as bad as the original. And it's much crisper. All in all, if you're happy with a tiny bit of soldering to bridge two tiny pads, it's a worthwhile upgrade.
#Sony #PSP
https://assets.oldbytes.space/assets.oldbytes.space/media_attachments/files/113/635/960/451/612/833/original/a5335d3f4fb851a0.jpg
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2024-12-06 09:41:22 GMT

I've got a pair of GameCube controllers, barely used and doing nothing (no GameCube). I'm not a big gamer, but it would be nice to have a pair of controllers to play the occasional game with my wife - emulated Mario Kart, some platformers, etc.
Am I better off buying a USB adapter for the GC controllers, or selling them and buying, say, an 8bitdo controller or two?
If it makes a difference, I'm on Linux.
#gaming #LinuxGaming #Steam #RetroGaming

2024-11-15 16:56:33 GMT

Current main projects:<li><a href="https://oldbytes.space/tags/CTRAN" class="mention hashtag" rel="tag">#CTRAN</a>: Start writing unit tests with FPCUnit. Also, complete a full write-up of what it took to get the thing working.</li><li>Get my website running <a href="https://oldbytes.space/tags/GoHugo" class="mention hashtag" rel="tag">#GoHugo</a></li><li>Rip the batteries out of the Revo I was given last week and assess the damage <a href="https://oldbytes.space/tags/Psion" class="mention hashtag" rel="tag">#Psion</a></li>
Immediately upcoming projects:<li>Rebuild of DEATH, my Microserver gen8, probably with <a href="https://oldbytes.space/tags/FreeBSD" class="mention hashtag" rel="tag">#FreeBSD</a>.</li><li>EMAKE: Complete recreation of the SIBO C SDK "linker" in <a href="https://oldbytes.space/tags/ObjectPascal" class="mention hashtag" rel="tag">#ObjectPascal</a>. To be started once I'm happy with CTRAN's unit tests.</li><li><a href="https://oldbytes.space/tags/ThinkPad" class="mention hashtag" rel="tag">#ThinkPad</a> T480 mods</li><li>Read some <a href="https://oldbytes.space/tags/compiler" class="mention hashtag" rel="tag">#compiler</a> related programming books</li>
These are just the ones I can think of right now.

2024-11-11 17:57:53 GMT

If I met you over the weekend at #RetroFest in Cambridge, please do make yourself known. I saw so many people it's difficult to put names to faces, so you might need to refresh my memory!
Every one of you made the weekend so worthwhile. Thank you.
#RCF2024 #RetroComputing

2024-11-09 20:56:01 GMT

It's been quite the day.
Same again tomorrow!
#Psion #RetroComputing #RCF2024 #RetroFest #VintageComputing
https://assets.oldbytes.space/assets.oldbytes.space/media_attachments/files/113/454/985/294/654/239/original/5d961f667f8eda2c.jpg

2024-10-30 11:41:10 GMT

Presenting my #MAME demo machine for #RetroFest 2024!
This is an EPOS unit. It's a Partner Audrey A4-1-A with a Celeron J3455 (2.3 GHz Apollo Lake) and 4GB RAM. It's a surprisingly well stacked machine - 4x USB 3, 2x serial, 2x GbE, HDMI out, VGA out, and on-board sound. The touchscreen is bright and clear, too.
So, what have I done with it? I've installed #openSUSE #Kalpa, created an #ArchLinux container with #distrobox and installed MAME in the container. It's running four copies of MAME (the #Psion SIBO emulator) and it's barely breaking a sweat!
This is my first time properly trying out an immutable distro, and I've been pleasantly surprised. It's Just Worked. I don't need this machine perfectly fine-tuned. I just need something quick and stable as a base, and to be able to easily run the latest version of MAME.
#retrocomputing #kde #microOS #immutabledistro
https://assets.oldbytes.space/assets.oldbytes.space/media_attachments/files/113/396/113/607/503/190/original/c0aada2661aae108.jpeg
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2024-10-28 16:09:19 GMT

Here's something I wish would be open sourced.
The #TopSpeed C #compiler is an integral part of the #Psion SIBO C SDK.
Old timers might remember JPI as a group of developers who left #Borland in 1987, after Borland decided not to use the team's new compiler technology. They took their code with them, and it became the TopSpeed compiler.
From what I gather, the TopSpeed compiler IP is now owned by #SoftVelocity, the company who now also owns Clarion. I emailed them about 6 years ago, asking them if they would consider open sourcing the compiler code. I got no response, which I guess is to be expected.
I even found someone who had a copy of the source code (written in Modula-2), but they understandably wouldn't give it to me without the IP owner's approval.
This is the situation with so many bits of software (including the SIBO C SDK tools) from this time. We are lucky that copies of the applications still exist, otherwise the job of building C software for #EPOC16 would be significantly more difficult. But it is likely that the original source code, along with many other codebases, will disappear thanks to copyright laws that don't support digital preservation.
#retrocomputing #vintagecomputing #digipres
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2024-10-12 19:01:46 GMT

Moved instance, so time for a new #introduction!
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.
6 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.
My current main projects are:<li><a href="https://oldbytes.space/tags/PsiDrive" class="mention hashtag" rel="tag">#PsiDrive</a>, an <a href="https://oldbytes.space/tags/RP2040" class="mention hashtag" rel="tag">#RP2040</a>-based USB drive for SIBO SSDs.</li><li>Rewriting the Psion SIBO (16-bit 8086) C SDK, including updating the docs (with <a href="https://oldbytes.space/tags/AsciiDoc" class="mention hashtag" rel="tag">#AsciiDoc</a>) and rewriting the original DOS tools as FOSS apps. I'm currently using <a href="https://oldbytes.space/tags/FreePascal" class="mention hashtag" rel="tag">#FreePascal</a> to create a drop-in replacement for <a href="https://oldbytes.space/tags/CTRAN" class="mention hashtag" rel="tag">#CTRAN</a>, the Psion OO C preprocessor. (I want to eventually write a new compiler targeting EPOC16. Eventually.)</li><li>Anything else that tickles my bouncy brain.</li>
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 #HaikuOS and I'm planning on giving #FreeBSD a go very soon.
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.
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