r/retrocomputing

Upgraded with a Boca Research Se1440 sound card
And 16Mb of ram
Running a 386 at 16MHz

I have a working PS/2 30-286 which I boot from a CF card but it always annoyed me that the original hard disk couldn't initialize. It only blinks and gives BIOs error codes. So instead of throwing it directly in the trash I thought why not create some 'don't do this at home' kind of video. So here goes. The drive is probably deader now than dead from the dust, but at least I can rest the case that the spindle motor really does not do anything. It's not only a hard disk drive but an immobile disk drive. No movement no data. It's a blinking LED now basically.

Edit: sorry I wrote 386 but it's a 286 obviously.

Over the past few weeks I've been reconstructing CHARM-II, an RTOS I originally developed in 1986.

Some previous posts about this project:

• Visualizing a 1986 RTOS in a Modern Browser https://www.reddit.com/r/osdev/s/XeZDemN4Wk
• Visualizing a 1980s Commercial Messaging System Running on a Reconstructed RTOS https://www.reddit.com/r/osdev/s/gu8LBK5iev

While working on those, I realized something that I had completely forgotten about the original development process.

When I started this reconstruction, I thought the challenge would simply be getting the old code running again.

Instead, I ended up rediscovering why I developed it the way I did.

Back in 1986, the RTOS was developed on a SUN-2 with a Motorola 68010 and deployed on a separate 68000 target board.

I had always remembered debugging the kernel on the SUN-2.

What I had forgotten was why I stopped there.

During the reconstruction, I realized that this had been a deliberate engineering decision.

A fully preemptive kernel, including interrupt handling, context switching, and processor state management, is by far the most hardware-dependent and complicated part of an RTOS.

Implementing all of that on the host would have made the project much more complicated.

So I postponed it.

Instead, I developed almost everything else on the host:

• queues
• events
• timers
• scheduling
• message passing
• application logic

By the time the software was moved to the target hardware, most of the debugging had already been completed.

At the time, I don't think I consciously thought of this as a development methodology.

It was simply the most practical way to make progress.

Forty years later, reconstructing the project made me realize how effective that approach actually was.

Interestingly, I ended up following almost the same process again.

The original SUN-2 has been replaced by a POSIX environment.

The target will be a Raspberry Pi Pico.

A browser-based visualization was added along the way, but the overall host-target workflow is remarkably similar.

One thing that surprised me during this reconstruction is that the biggest changes rarely came from the original plan.

The browser visualization, for example, was inspired by WebAssembly that I encountered while working on an unrelated project.

It reminded me that engineering projects often evolve through unexpected discoveries rather than carefully planned roadmaps.

I'm curious whether anyone else has experienced something similar.

Have you ever reconstructed an old operating system, or any long-lived system, and discovered that the original engineering decisions made much more sense decades later than they did at the time?

Under the main CPU, you can also spot an empty footprint for a directly soldered PQFP 486 processor — basically the hardware equivalent of the "you are broke" blank buttons on base-model cars.

The PCB was designed to support a socketed PGA 486, a soldered PQFP 486, or even both at the same time, depending on the manufacturer's configuration.

Was given some of these older software discs (2002-2011). I'm not really into computing. Any idea what to do with them? Maybe I can donate somewhere? I figured they've probably been archived already.

Hello ive recently put my hands on a beautiful IBM p202 crt and sadly it doesn’t works
Im willing to give it a try restoring it but im gonna need some help,
The tv itself turns on with the light green, after a few seconds it becomes orange telling its going to sleep
When I long press the blue button to do a video test, the tube comes on and it shows a black screen with horizontal lines,so the tube itself isn’t dead.
Also when I long pressed the contrast up button to do a color check, the tube doesn’t even turns on.

Because after reading the documentation and finding out that there are no error codes, I’ve tried plugging a pc to the VGA port on the back, the tv then exit sleep mode and the led turns on telling it detected the computer, but weirdly the tube doesn’t light up at all and it’s only when I shut off the tv that I briefly see my pc desktop video flash on the tube .

I’ve already disassembled the whole tv and I didn’t see any signs of leaking capacitors or damage visually.
I don’t know where the issue is from and I hope someone’s gonna have an idea?

IBM PS/2 25SX

Only need to get a new floppy drive and she’s good

Some notable microcomputers and consoles:

* TRS-80 Model I (1977)

* TRS-80 Model III

*TRS-80 Model 4

*Sinclair ZX80

*Sinclair ZX81

*ZX Spectrum

*Amstrad CPC 464

*Amstrad CPC 664

*Amstrad CPC 6128

*MSX computers

*Sharp MZ-80K

*Kaypro II

*Osborne 1

*Sega SG-1000

*Sega Master System

*Sega Game Gear

* Game Boy (uses the Sharp LR35902, a CPU derived from the Z80 and Intel 8080, not a full Z80)

...As secondary cpu:

*Sega Genesis / Mega Drive (sound CPU)

*SNK Neo Geo AES (audio CPU)

*SNK Neo Geo MVS (audio CPU)

Famous arcades:

*Pac-Man

*Galaga

*Bubble Bobble

*Double Dragon

and countless other machines and handleds

Behold my little collection, with room for more!

do not take this post seriously :^)

Hello, I found this IBM Aptiva in the trash, and luckily it works, but some plastics are broken, does anyone know how to fix them without making a mess?

Thanks

More...

From someone who set out with his 40-year-old SX-64 to visit an equally ancient Commodore 64 BBS - not old-school with a modem, but through a DIY null-modem cable hooked up over the internet.

https://www.youtube.com/watch?v=3csC9z7oPSY

It turned out to be much more difficult than expected, with all sorts of cable shenanigans that of course refused to work - and ultimately even resulted in the SX‑64 needing repairs.

I got an old computer (from around 1999 I think) and it came with everything but the hard drive, so I bought a 320GB Ultra ATA Seagate ST310014ACE. I tried installing/ plugging it inside my PC many times, in many ways, but everytime I try to install Windows XP x86 SP3 it tells me "Setup cannot access this disk​" in the partition selection screen. Does anyone know how to fix this?

If it helps, the motherboard is P6V693A/A9 with an Intel Celeron.

The Dell Inspiron 8200 wasn't just a high-end laptop—it was built to replace a desktop. With desktop-class performance, a 1600×1200 UltraXGA display, nearly every port you could ask for, and Dell's modular Media Bay, it was one of the most capable portable workstations of its time.