os8088: A Mac-like OS for the IBM XT, 286, 386
Os8088: A powerful Mac-like OS for the IBM XT, 286, 386
os8088 is a graphical operating system for the IBM PC XT, written entirely in real-mode assembly and booted from a floppy. It brings a Macintosh System 1-style desktop to 8086/8088 machines, featuring overlapping windows, pull-down menus, a serial mouse, and pre-emptive multitasking—something the original 1984 Macintosh lacked. The kernel fits in 52,718 bytes, runs in 256K of RAM, and supports VGA, Hercules, or CGA displays. Programs load from a second floppy and run concurrently, with a Task Manager showing CPU usage. It runs on real hardware, including a 1981 IBM 5150, and is a hobby project with source available.
Five programs at once, on a CPU from 1978.
- adrianmonk
> 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.
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.
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- Narishma
> Hand-written real-mode 8086. No C, no linker, no runtime library.
More like hand-prompted...
- garganzol
LLM writes a better ASM then a C compiler? From running the demo in the browser, it seems so performance-wise and size-wise, but the ultimate test should be performed on a real hardware that I have no direct access to.
Anyone can validate the performance on a real PC of the era? If it's confirmed, LLMs may be one of the ways of creating highly optimizing compilers in the future.
- LeoPanthera
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.
- orbital-decay
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.
- yjftsjthsd-h
https://os8088.com/how-it-works/multitasking/
> Pre-emptive multitasking on an 8086
> Twelve task slots, 1,536 bytes of stack each, and a timer interrupt that takes the CPU away from whatever is running 18.2065 times a second. No task is asked to cooperate and no task can refuse.
If you don't have protected mode, can't any program just rewrite the interrupt handler? It's not a bad system, but it sounds easy to break.
- jggonz
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.
- baud9600
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: