Who wants a deep-dive into a tiny aspect of Psion SSDs and their ASICs?

I was using a PsiDrive a couple of months ago to dump a 2MB SSD. However, when I tried to extract the files, my FEFS extraction tool (siboimg) segfaulted halfway through. So, as I was in a rush, I decided to come back to it another day. Yesterday was that day.

My first thought was that it could be a problem with the Pico 2, either with the code or the RP2350 A2 stepping chip. So, a couple of days before, I built a second PsiDrive and put in a Pico 1. But the fault remained with with Pico 1.

At the beginning of 2024, I ragequit reading about Psion’s proprietary Object Oriented C.

This was unexpected, but I should have seen it coming.

Near the end of the previous November, I made an announcement on social media. I was going to start working on a new word processor for Psion’s 16-bit portable machines. I’d been working on Psion-related projects since September 2018, focusing on the SIBO/EPOC16 platform. Writing a replacement for Psion Word was one of the first ideas I’d had. So, as I’d spent the latter half of 2023 bouncing between projects and never quite settling, I decided that now was the time. It was to be called Vine, a nod to both the codename of the Psion Siena and the Vi-like bindings I was hoping to include in its feature set.

Me: I could do with a quick win to get me going again.

Also me: I shall learn a proprietary object oriented dialect of C, where the only way to learn it is to plough through 1150 pages of documentation.

Psion doesn’t have a formal name for the object oriented version of C that it created for EPOC16. I’ve been calling it “Psion OO C”, but the main library that it uses is called OLIB, which contains the root class. The others are:

It’s been a while, hasn’t it?

My work on this project has been relatively sporadic over the past 12 months. I’ve not found it easy to find a balance between this, my day job, and other projects I’m working on. As a result, there have been some relatively intensive periods of work on Psion shenanigans, followed by burnout or other priorities needing to take precedence.

Finally, it’s here! Some proper code for reading SSDs and (eventually) other SIBO peripherals.

I’ve spun off some the Arduino code from SIBODUMP, added the FlashFS code from SIBOIMG, ported it to PlatformIO, and pushed it to GitHub.

So, the TL;DR is:

• Two major bugs squished.
• It works with more boards now (Pico, ESP32, Arduino Nano)
• It’s still uses the Arduino libraries, but it’s now based on PlatformIO
• You’ll need level shifters for 3.3v (I’ve included an example)
• Would regular Raspberry Pi compatibility be useful?
• Next steps
• Discord chats

So, take a look at the code over on GitHub Codeberg, then read on.