Computer-generated dream world: Virtual reality for a 286 processor

https://deadlime.hu/en/2026/02/22/computer-generated-dream-world/

by MBCook • 5 months ago

146 29 5 months ago

deadlime.hu

01HNNWZ0MV43FF• 5 months ago

So they're stepping a 286 very slowly and sorta... bit-banging the I/O pins on it?

Love it. No notes.

st_goliath2• 5 months ago

I've seen a similar project a while ago and thought this was about the same thing at first: [1][2]

Both essentially built a DIY chip tester for a 286 and both built around a Harris 80C286.

If I understood it correctly, the goal behind this project seems simulating the rest of the PC, purely for the challenge and learning experience, documenting the process of building the chip tester (and getting mildly philosophical in the process).

The other project was more directly interested in the 286 itself, undocumented instructions, corner cases in segmentation behavior, instruction cycle timing, etc. and also trying to find out if there are any difference between the Harris and Intel variants.

[1] https://forum.vcfed.org/index.php?threads/286-cpu-experiment...

[2] https://github.com/dbalsom/arduinoX86

dividuum• 5 months ago

Here's a project that also does this to ensure cycle-accuracy for their emulator: https://github.com/dbalsom/arduinoX86

theginger• 5 months ago

Looking at the amount of wires going into this, my instinct is that this cannot scale, in 5-10 years this won't be doable for a Pentium chip, at least not as an at home hobby project. But I actually think it could go the other way, and in 5-10 years you'll be able to do this at home for far more sophisticated kit, unlocking crazy amounts of reverse engineering possibilities that were once thought of as near impossible, or at least only possible for a nation state scale setup.

st_goliath2• 5 months ago

I'm pretty sure if you really want to, you could do something like this as a hobbyist with a Pentium right now.

Instead of futzing with wires on a breadboard you could simply designing a PCB up front, throw the design over the fence at JLC or PCBWay, insert coin, wait patiently at the mailbox, solder your scavenged Socket 7 onto the board.

The days of toner transfer and aquarium pumps are already long gone. Getting production quality, one-off, multi layer PCBs done as a hobbyist is dirt cheap these days, no government budgets required.

duskwuff• 5 months ago

I don't know about Pentium, but there's definitely some homebrew 486 projects out there, e.g.:

https://maniek86.xyz/projects/m8sbc_486.php

ErroneousBosh2• 5 months ago

you could simply designing a PCB up front, throw the design over the fence at JLC or PCBWay, insert coin, wait patiently at the mailbox

It blows my mind that I can use free-as-in-beer Free-as-in-Speech software to design a PCB, email it to a dude in China, and get a finished working professional-looking PCB back in my hand within a week, for the price of a couple of coffees. And if I want the components stuck on too, it'll cost a little extra, maybe three coffees it costs now.

If I want it really quickly then for the price of a decent takeaway curry I can have it flown over next day. What the actual hell?

Edit: the slowest part of "next day" is when it hits the UK, and if I could guarantee it just gets delivered to DHL's Edinburgh depot I could drive down there in two hours.

dsign2• 5 months ago

Cool! But the wires!

I'm not a fan of breadboards, they tend to be unreliable even for trivial circuits. We need something more affordable and practical for home PCBs[^1]. Why is it that nobody has invented a tin 3D printer, or at least a 2D version of it, i.e. a tin plotter?

[^1]: I'm discouraged from home-etching by the chemicals and the dark-room part of the process.

vhab• 5 months ago

Bad Obsession Motorsport actually went this route, you can see their custom printer on their youtube[1] channel

[1] https://www.youtube.com/watch?v=FzrZoVKT8gM

ZiiS2• 5 months ago

For $2,500 the Carvera Air makes very nice 2 sided pcbs with solder mask. Though even in raw materials it is hard to match a finished board from China if you can wait a couple of months.

wolvoleo• 5 months ago

In my experience it's a couple of weeks, not months from China.

asdefghyk2• 5 months ago

wirewrap circuit construction would be more reliable. However high speed (if needed ) could be a problem ? from crosstalk.

fatnoah• 5 months ago

I worked at a no longer extant networking equipment manufacturer as an intern in college in the late 1990's. My role was to work on software for an in-development 45Gb network switch, and a bunch of the software I wrote ran on prototype boards.

Since fabricating new boards took time and was expensive, a lot of work was done to make in situ modifications that involved an insane amount of wirewrapping. One member of the team did that all day, every day as their full time job, and I was always amazed by their ability to focus consistently at that level for so long.

asdefghyk2• 5 months ago

One maybe unrecognized problem, of breadboards is not so good for high speed digital circuits due to capacitance

coderjames2• 5 months ago

For the 2D version, you might not need very much custom. Use a regular pen plotter and use a pen with conductive ink. These both exist today, though personally as a hobbyist PCB designer, I can get 2-layer and 4-layer boards cheap enough from JLCPCB or Oshpark or PCB Unlimited that I don't bother trying to make them myself.

jrmg• 5 months ago

I always thought conductive ink had too high a resistance to use to make PCBs. That’s not the case?

How do you attach the components to it?

estimator7292• 5 months ago

My last job had a desktop CNC called Volterra I think. It would squeeze out conductive ink, bake it, drill holes, and lay down and reflow solder paste.

It was expensive and performed terribly.

I think there really isn't any good way to improve on breadboards. Breadboards, in fact, are the improvement. They're called breadboards because we used to literally drill pieces of wood and do wire-wrap construction on the other side.

Breadboards are good enough for the kind of prototyping they're for. Spring loaded contacts are about the best you can get for removable parts. The signal integrity isn't that bad at modest speeds.

In today's world, the next step up from a breadboard is custom PCBs. You can have a set of five shipped from China for the same price as a set of breadboards. There's no real need or reason for anything in between so long as PCB manufacturing is so disgustingly cheap and fast.

kevin_thibedeau• 5 months ago

Just use a fabrication service. You can't readily make plated through holes and vias at home. The services do a much better job than any hobbyist level tinkering can achieve.

tl2do• 5 months ago

I'm Japanese, and the 80286 at 10MHz was huge for Japan's PC-98 scene. The V30 handled backward compatibility while the 286 ran much faster than what we had before. This project brought back memories—the 286 was the chip of my era, and it's great to see people still exploring its capabilities decades later.

valorzard• 5 months ago

Japanese PC-98 games have an aesthetic that’s so unique. There’s this one Twitter account that posts images from visual novels from that era and they all look so pretty: https://x.com/PC98_bot Also on bluesky https://bsky.app/profile/pc98bot.gang-fight.com

livestories• 5 months ago

Reminds me of the Tamagotchi Matrix:

https://hackaday.com/2015/11/24/building-the-infinite-matrix...

markbnj• 5 months ago

Ha, little fall down the memory hole. I had a Harris 20mhz 286 back in the late 80's. I thought that thing was a beast at the time. Paired it with a Conner 100MB disk and I remember my brother laughing derisively, "Who the hell needs 100 megabytes?"

iberator• 5 months ago

Very impressive to use intel cpu without BIOS. Real hacker

forinti• 5 months ago

My first computer was a 286 with 1 MB of RAM and a 50 MB HDD

That was the configuration I had when I went to college. I had an amber monitor that had a really crisp image and 5.25" HD floppy drives. The AT case was fantastic, I wish I had one today.

Computer-generated dream world: Virtual reality for a 286 processor

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