@thelastpsion@bitbang.social
@thelastpsion@bitbang.social avatar

thelastpsion

@thelastpsion@bitbang.social

Vintage platform necromancy. #Psion hardware and software hackery, especially SIBO/EPOC16 machines (Series 3, etc).

Made the #PsiDrive, a USB drive for Psion SSDs. Slowly rewriting the SIBO SDK.

WARNING: Will #sidequest (#HaikuOS, #Linux, #BSD, #NeoVim, #virtualisation #virtualization, #Arduino, #RP2040, #PlatformIO, #FreePascal #ObjectPascal, #ObjC, #compilers)

If you have old Psion source code (OPL, C, C++, assembly), docs or schematics, get in touch!

#retrocomputing #permacomputing

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thelastpsion, to retrocomputing
@thelastpsion@bitbang.social avatar

Now in - 0.265!

Sorry, I meant to post this last week (see the date of the screenshot), but I've been tied up with other things.

x64 only - i686 fails at linking, because it's just too big for 4GB. I'll try to work on that when I set up an i686 installation of Haiku.

As usual, showing off screenshots, because of course.

BTW, is running via SSH on the Haiku box (r1b4). It's more stable on nightly, so I'm looking forward to r1b5!

thelastpsion, to foss
@thelastpsion@bitbang.social avatar

I'm in the mood to try to get more old software open sourced. If you can think of any old apps that you used on your Series 3a (or Series 5/Revo, but you all know I'm more of a SIBO/EPOC16 fan) that you remember fondly, I'll see if I can track the developer(s) down.

thelastpsion, to zig
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Random thought:

Objective-Zig.

Discuss.

thelastpsion, to retrocomputing
@thelastpsion@bitbang.social avatar

The "spares or repair" Series 5 had arrived.

It does not look good.

thelastpsion,
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There's a chance that this ROM board might be salvageable. But it's a small chance. At least the chips look OK.

thelastpsion,
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COMPATIBLE CHIPS FOUND!

Samsung KM416V1000BT-L6. Not the best option, but definitely compatible and perfect for testing.

The bottom one has been affected by corrosion, but the top three are in good condition.

The board also has two microswitches (top-right of the picture) that I can use to repair another 3mx.

Sweet Series 5, your death will not be in vain!

thelastpsion,
@thelastpsion@bitbang.social avatar

This is really exciting for me, because it's now very likely that I'll be able to bring a working 4MB Series 3mx to the Festival of Portable Computing in next month. As far as I know, it'll be the only one in the world!

https://www.computinghistory.org.uk/det/72231/The-Festival-of-Portable-Computing-(18th-19th-May-2024)/

thelastpsion, to retrogaming
@thelastpsion@bitbang.social avatar

Current projects:

▶️ : A drop-in FOSS replacement for CTRAN.EXE, the SIBO/EPOC16 OO C preprocessor on . Almost feature complete, but still work to do!
▶️ with : Used for CTRAN for easy development and portability. Honestly, I'm really enjoying it; it fits my needs and makes my brain happy.
▶️ RAM upgrade for 3mx to 4MB: Trying to source old DRAM isn't easy.
▶️ RAM upgrade for 5mx: Got the DRAM. Just need to solder it in place.

thelastpsion,
@thelastpsion@bitbang.social avatar

Upcoming projects:

⏸️ Learn 's proprietary 16-bit OO C.
⏸️ Rewrite more of the SIBO SDK.
⏸️ Learn about designing and .
⏸️ New version of PCB.
⏸️ Vine: A new word processor aimed at writers/authors, with Vim motions and compatibility.
⏸️ Converting the Psion SIBO C SDK to AsciiDoc.
⏸️ : Like but for Flash (FEFS) volumes.
⏸️ null modem mod, so that it can talk properly to .
⏸️ psion.info redux.
⏸️ More docs!

thelastpsion,
@thelastpsion@bitbang.social avatar

I need to prioritise those pending projects, because just thinking about all that work makes me anxious. Even though IT'S MY CHOICE TO DO IT ALL!

I'm also not including all the random projects that pop into my head, like the and ports. Not to mention every time I think of a video I could make on any and all of these topics.

One thing at a time...

thelastpsion, to retrocomputing
@thelastpsion@bitbang.social avatar

It's official! I'll be at the Festival of Portable Computing on the 18th and 19th of May, at the Centre for Computing History in Cambridge, showing off my collection of Psion kit.

The collection has grown since last year, so let's see what I can fit on a table! 😂

I've also got a small collection of non-Psion kit in various states of disrepair, so I'll bring those too.

https://www.computinghistory.org.uk/det/72231/the-festival-of-portable-computing---18th---19th-may-2024/

thelastpsion, to random
@thelastpsion@bitbang.social avatar

I have come to the conclusion that compiler writing is in my future. I have repeatedly told myself it's a terrible idea. I have even publicly said I'm not going to do it unless someone pays me a lot of money.

But the money won't happen. I know I'm going to do it anyway.

It's a next year problem. I have other projects to complete first, plus It'll take me at least that long to gain a fraction of the knowledge I need to start.

CTRAN was the start, and it gave me a tiny taste. I even liked it.

thelastpsion,
@thelastpsion@bitbang.social avatar

As of right now, the feature list (subject to change, due to my current limited knowledge) is:

Compiler for EPOC16

  • Target: 8086; NEC V20 extensions
  • Language: C89, some C99 features; Objective-C extensions
  • Replicate the output of JPI/Clarion TopSpeed C 3.10 as closely as possible (pure small memory model)
  • Runs on: Linux, HaikuOS, Windows, *BSD
  • Written in: TBD. Pascal/Rust?/OCaml? (can't use Go as there's no port for Haiku yet)

I can't emphasise enough: I DO NOT KNOW WHAT I'M DOING!

thelastpsion,
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@M0CUV Thank you for asking! I'll have to let you know nearer the time. I've got other projects to finish and a lot to learn before I can even begin to think about starting this one.

thelastpsion,
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@M0CUV I've seen this! She's one of the people that I saw mentioning OCaml for compiler writing. In fact, I think she used it for the book. https://norasandler.com/2017/11/29/Write-a-Compiler.html

thelastpsion, to random
@thelastpsion@bitbang.social avatar

What is the best way to learn on Linux?

At some point in the future I want to get a feel for the language. I'm not so fussed about learning Cocoa and the Foundation framework. I'm more interested in the syntax and structure.

I need something with a solid set of tutorials, without using a Mac.

Is the best option? Are there any good tutorials for ?

thelastpsion, to retrocomputing
@thelastpsion@bitbang.social avatar

I've spent so much time working on Psion stuff recently that I've neglected to actually use my 3mx.

A lovely evening, so it feels right to do some writing in the garden.

thelastpsion, to random
@thelastpsion@bitbang.social avatar

Looking at the 4MB 3mx again.

With ASIC9 machines (3a, 3c, 3mx, Siena, Workabout), RAM above 384K is paged in in 64K banks. The newly added 2MB is in banks 0x20-0x3F.

There are definite similarities in what's stored in 0x20-0x23, with some bytes just having one bit flipped. It then changes again for 0x24-0x27, 0x28-0x2B, 0x2C-0x2F. For all of those, the 4 high bits are predominantly on, and the 4 low bits predominantly off.

Bank 0x21 of RAM, compared with bank 0x20. Dumped from the "victim" 4MB 3mx with EDisAsm. Displayed using VBinDiff.
Bank 0x22 of RAM, compared with bank 0x23. Dumped from the "victim" 4MB 3mx with EDisAsm. Displayed using VBinDiff.
Bank 0x23 of RAM, compared with bank 0x22. Dumped from the "victim" 4MB 3mx with EDisAsm. Displayed using VBinDiff.

thelastpsion,
@thelastpsion@bitbang.social avatar

Has anyone in the UK had any luck with ordering components from suppliers listed on DigiPart? If I can't find a donor part with the right DRAM chips (I don't want to cannibalise another 3mx), then it looks like that might be the way I have to go.

There's also a UK-based company called LittleDiodes. No idea what they're like.

EDIT: It's LittleDiode, without the S.

thelastpsion,
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While witing for LittleDiode to get back to me, another option for the DRAM is utsource. They sell this, used:

https://www.utsource.net/itm/p/461976.html

Reviews of utsource are mixed, but I guess there's risk when sourcing any old parts.

They offer "Plus" membership on a 30 day trial, which comes with a voucher that would cover delivery. I could get 5 for about £9 + VAT. They would also check the parts before shipping, although I don't know what "check" really means.

Anyone used utsource?

thelastpsion,
@thelastpsion@bitbang.social avatar

Slightly worrying - the description doesn't match the model number. Hmm...

From utsource: Product Attributes Description: KM416V1000CT-L6 is a 1 Gb (128M x 8) Synchronous DRAM, organized as 131,072 words by 8 bits. It is a TSOP (Thin Small Outline Package) with SEC (Single Edge Contact) type. Features: - Fast page mode access time: 10ns - Single 3.3V power supply - Auto and self refresh - Programmable burst lengths (1, 2, 4, 8) - Programmable burst type (sequential and interleave) - Data masking - Data bus inversion - On-chip address and control registers - Package: 48-pin TSOP (Thin Small Outline Package) with SEC (Single Edge Contact) type Applications: - Networking equipment - Graphic cards - Embedded systems - Industrial automation - Automotive systems (For reference only)

thelastpsion,
@thelastpsion@bitbang.social avatar

I've found a website belonging to a small IT company in the UK. The site hasn't been updated in a long time, but it says that they have (had) over 200 of a 3mx-compatible DRAM chip in stock.

According to Companies House, the company is still active.

I've emailed them.

If nothing else, they might be able to tell me what equipment that DRAM chip went into. If I'm lucky, it's cheap and there are loads of them.

thelastpsion,
@thelastpsion@bitbang.social avatar

I've had a reply. He's going to check his stock on Monday.

😬

If he has stock, I really hope I've got the right chip! I've checked multiple times, but you never know.

thelastpsion,
@thelastpsion@bitbang.social avatar

I have read these datasheets an excessive number of times, but can someone please check for me?

Parts known to work on a 3mx:

  • Samsung KM416V1000BT-L6
  • Oki M51V16165DSL-6 (also listed as MSM51V16165DSL-60) TS-K

The part from the supplier:

  • Samsung KM416V1004CT-L6

The original Samsung DRAM is Fast Page Mode only. The Oki DRAM is FPM with EDO. The new DRAM is FPM with EDO.

They're all:

  • 60ns
  • TSOP-II-50-44
  • self-refresh, 4096 cycles, 128ms
  • 3V3
  • 12 row 8 col addressing

Front page of the Oki MSM51V16165DSL-60TS-K datasheet.
Front page of the Samsung KM416V1004CT-L6 datasheet.

thelastpsion,
@thelastpsion@bitbang.social avatar

No luck with the old DRAM from that supplier. I've given them a list of other compatible parts, but I'm not holding out much hope.

The only other option I've found is the Psion Series 5. Turns out they used many of the same parts, including the DRAM! The only issue is that some use slower chips (70ns) than the ones I've found in the 3mx (60ns). It might not matter, but I'll need to do some tests.

I've ordered a dead S5 from eBay. I'll see what's wrong with it, then maybe harvest it for parts.

thelastpsion,
@thelastpsion@bitbang.social avatar

Reply from LittleDiode. It's not good news.

How can a chip that was popular enough to be made by multiple companies no longer be available?!

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