The graphical operating system that could have been for the IBM XT.
A MacOS-like desktop for the Intel 8086, written entirely in real-mode assembly (with Claude). Verified to run on real hardware, with FAT12/16 support, ported apps, games, Sound Blaster support and upcoming Hard Drive support.
This rewrites what-could-have-been history a bit... better get my IBM XT/286 out of storage! Is this for real?
drivers99•Aug 9, 2026
I might have to try it out. I have an 8088 IBM PC (my first computer) on a desk. I need to swap out some bad RAM (I've been getting Parity errors and other strange behavior), but it says it works with 256KB so I could remove the AST SixPakPlus altogether. The fully populated mother board has 256KB. (I could also unplug the MFM hard drive controller as well.) It supports CGA and VGA and I have both (the CGA is original; the VGA is an 8-bit ISA one I picked up a couple years ago). I also have a serial mouse... Right now I have one floppy disk that came with a book I re-bought recently (Peter Norton's Guide to Assembly Language) and I could back up the files from it and use that but I think I'd rather buy/find another one to use. And I need more than one disk for this anyway.
Interesting, it currently says, 'Nobody has yet written the images to 5.25" media and booted an actual XT with them.'
cheema33•Aug 9, 2026
If it were available back then, Microsoft may be a small shop today or may have gone the way of Lotus.
MiroslavPokorny•Aug 9, 2026
You mean like the Amiga or Atari ?
Narishma•Aug 9, 2026
> Hand-written real-mode 8086. No C, no linker, no runtime library.
More like hand-prompted...
userbinator•Aug 9, 2026
I'm surprised Claude is actually decent at real-mode Asm, but maybe there was a lot of attempts and guidance by the human.
nineteen999•Aug 9, 2026
Ive been throwing z80, 6502, 68000, 8086, i386 and x86_64 asm at it lately. Haven't seen it get stuck on any of them.
MiroslavPokorny•Aug 9, 2026
github ?
paulryanrogers•Aug 9, 2026
Do you think the low-level nature of ASM contribute to how successful the LLMs are with it?
vunderba•Aug 9, 2026
From the landing page:
> 66,183 lines of hand-written real-mode assembly
Goes to the github - contributers jggonz and CLAUDE. The README.md doubles down on this at the bottom with the license.
> Everything here is hand-written; no third-party code is vendored into the OS, so the whole tree is covered by that one license.
That's what happens when you let an LLM write your ad-copy...
ButlerianJihad•Aug 9, 2026
It can't be written by LLM -- the human author has claimed copyright
> Everything after that is the interface you remember from a 1984 Macintosh: […] and a dock along the bottom with one tile per running program.
In that case I look forward to seeing OS X’s Aqua ported to the IBM PS/2.
userbinator•Aug 9, 2026
In that case I look forward to seeing OS X’s Aqua ported to the IBM PS/2.
If this project is any indication, AI can definitely make that happen too.
skissane•Aug 9, 2026
I’ve got nothing against AI-written code
But if people are going to post it on HN, they should consider at least writing the README / main page of their website by hand
It is nice to hear the human authorial voice, at least sometimes
winocm•Aug 9, 2026
The assembly really, really hurts to read.
internet2000•Aug 9, 2026
Fun little toy. Wonder how much in tokens went into it.
anigbrowl•Aug 9, 2026
Was not expecting the fractal viewer (in disk B/apps)
LeoPanthera•Aug 9, 2026
It's funny how virtually everyone on HN is using AI to write code and simultaneously dismisses all interesting new software as written by AI.
superb_dev•Aug 9, 2026
It’s almost like those are two different populations of people?
LeoPanthera•Aug 9, 2026
Outside in the real world? Sure.
Here on HN? I don't believe that.
1bpp•Aug 9, 2026
Different groups, the spammers like to congratulate each other for how much hard work they must have put into their very impressive prompt engineering. Regardless, AI code is distinct from extremely blatant AI design. People dismiss things that had no actual design, just whatever fell out of the prompt they gave it. If you can't write a single human paragraph or put thought and care into how you are presenting 'your' project, it's not worth paying attention to. Why can't they present their own work honestly? Why would I spend energy looking at an OS made by someone who can't write an HTML file by themself?
userbinator•Aug 9, 2026
There are both pro- and anti-AI factions here... and those with more nuanced views.
Personally, I don't care as long as the end result is good, but a lot of AI software tends to be in the lower end of the quality range.
accrual•Aug 9, 2026
I agree, and I think one can put in more effort on a project and get a better result, especially if the prompter is already an experienced software developer. For example on one toy project I requested the use of ADTs (algebraic data types), strict linting and code formatting at every commit, tests, frequent code review rounds, and a strong initial plan which led to a very solid personal-use project.
Similar strategy can help smaller local models achieve greater results too. Small steps + many guardrails.
orbital-decay•Aug 9, 2026
Beveled-buttons Minesweeper (first appeared in Win 3.11 IIRC) running on a preemptive 8086 OS with a bootleg System 1/2/3 interface looks absolutely cursed.
nianderwallace•Aug 9, 2026
You'd still need a Wordstar-like app and a VisiCalc-like app (pref. Lotus 123-like).
VGA adapter means you have to wait until 1987 to run this, otherwise you'd deal with CGA's non-square pixels. EGA support would only be possible in Oct 1984.
rickcarlino•Aug 9, 2026
The website explicitly states a lack of networking. Any interest in pursuing that in a future version?
I have a Pocket 8086 - I would love to give this a try next weekend.
badsectoracula•Aug 9, 2026
Nice, Solitaire in 7KB of RAM[0]. Sadly it only says "You win!" if you win, no bouncing cards animation :-P.
It looks surprisingly Mac-like, except the font kind of spoils the illusion.
adrianmonk•Aug 9, 2026
> The graphical operating system that could have been for the IBM XT
Visi On[1] was a graphical operating system for the IBM PC that actually existed as a commercial product, though definitely not a very successful one. It was made by VisiCorp, the same company that created VisiCalc (the first spreadsheet for a personal computer).
It was demoed at COMDEX in 1982, before the Apple Lisa was released. It came out after the Lisa but slightly before the Macintosh.
Fun fact: Bill Gates saw the demo at COMDEX, and at first he was skeptical that it was really running on an IBM PC. But ultimately he was so impressed he decided[2] to start developing a product called Microsoft Windows.
This kinda almost makes it sound like VisiOn introduced Gates to the GUI which is not true. They were already using and developing for Macintosh machines at Microsoft and had hired Charles Simonyi from PARC with his expertise in GUI systems before Comdex 1982.
The story seems to be more that seeing VisiOn gave MS the nudge to get into action on the GUI due to a sense of competition/urgenbcy from VisiOn rather than learning about the GUI from VisiOn.
baud9600•Aug 9, 2026
This is great -
It’s almost as impressive as the “GOS” written for Atari 8-bit running on 6502 at 1.79 MHz. Visually it’s almost identical but has a nicer font. The specs are somewhat similar with 16 task slots, calculator app and task manager, serial mouse support (ST mouse) and Atari’s hardware sprites helping with some of the graphics. The XOR window frame is the same idea. Amazingly, Atari GOS runs in 128K of RAM! One has to admire the work and inventiveness in these projects. See description and videos here:
14 Comments
A MacOS-like desktop for the Intel 8086, written entirely in real-mode assembly (with Claude). Verified to run on real hardware, with FAT12/16 support, ported apps, games, Sound Blaster support and upcoming Hard Drive support.
Amazing.
https://github.com/bluewaysw/pcgeos
Interesting, it currently says, 'Nobody has yet written the images to 5.25" media and booted an actual XT with them.'
More like hand-prompted...
> 66,183 lines of hand-written real-mode assembly
Goes to the github - contributers jggonz and CLAUDE. The README.md doubles down on this at the bottom with the license.
> Everything here is hand-written; no third-party code is vendored into the OS, so the whole tree is covered by that one license.
That's what happens when you let an LLM write your ad-copy...
https://news.ycombinator.com/item?id=49203613
> Everything after that is the interface you remember from a 1984 Macintosh: […] and a dock along the bottom with one tile per running program.
In that case I look forward to seeing OS X’s Aqua ported to the IBM PS/2.
If this project is any indication, AI can definitely make that happen too.
But if people are going to post it on HN, they should consider at least writing the README / main page of their website by hand
It is nice to hear the human authorial voice, at least sometimes
Here on HN? I don't believe that.
Personally, I don't care as long as the end result is good, but a lot of AI software tends to be in the lower end of the quality range.
Similar strategy can help smaller local models achieve greater results too. Small steps + many guardrails.
VGA adapter means you have to wait until 1987 to run this, otherwise you'd deal with CGA's non-square pixels. EGA support would only be possible in Oct 1984.
I have a Pocket 8086 - I would love to give this a try next weekend.
[0] http://runtimeterror.com/pages/iv/images/b869a0cf44a7e7cbc40...
Visi On[1] was a graphical operating system for the IBM PC that actually existed as a commercial product, though definitely not a very successful one. It was made by VisiCorp, the same company that created VisiCalc (the first spreadsheet for a personal computer).
It was demoed at COMDEX in 1982, before the Apple Lisa was released. It came out after the Lisa but slightly before the Macintosh.
Here's their promotional video from 1983: https://www.youtube.com/watch?v=kc4wFeVvKTI
Fun fact: Bill Gates saw the demo at COMDEX, and at first he was skeptical that it was really running on an IBM PC. But ultimately he was so impressed he decided[2] to start developing a product called Microsoft Windows.
---
[1] https://en.wikipedia.org/wiki/Visi_On
[2] https://en.wikipedia.org/wiki/Windows_1.0
The story seems to be more that seeing VisiOn gave MS the nudge to get into action on the GUI due to a sense of competition/urgenbcy from VisiOn rather than learning about the GUI from VisiOn.
It’s almost as impressive as the “GOS” written for Atari 8-bit running on 6502 at 1.79 MHz. Visually it’s almost identical but has a nicer font. The specs are somewhat similar with 16 task slots, calculator app and task manager, serial mouse support (ST mouse) and Atari’s hardware sprites helping with some of the graphics. The XOR window frame is the same idea. Amazingly, Atari GOS runs in 128K of RAM! One has to admire the work and inventiveness in these projects. See description and videos here:
https://atari8.co.uk/gui/