reactos / reactos

A free Windows-compatible Operating System

PureDarwin / PureDarwin

Darwin is the Open Source core of macOS, and PureDarwin is a community project to extend Darwin into a complete, usable operating system.

unikraft / unikraft

A next-generation cloud native kernel designed to unlock best-in-class performance, security primitives and efficiency savings.

nuta / operating-system-in-1000-lines

Writing an OS in 1,000 lines.

nanovms / nanos

A kernel designed to run one and only one application in a virtualized environment

illumos / illumos-gate

An open-source Unix operating system -- this is a read-only mirror of the official repository at https://code.illumos.org/plugins/gitiles/illumos-gate

HelenOS / helenos

A portable microkernel-based multiserver operating system written from scratch.

aros-development-team / AROS

Main AROS repository for active development. Contains the main Operating System components and Build System.

littlekernel / lk

LK embedded kernel

LearningOS / os-lectures

https://learningos.cn/os-lectures/ 2026年春季OS课程Slides\实验指导\思维导图\挑战项目等

Supercip971 / WingOS

a little 64bit microkernel based operating system written in c++ with smp support

mikaku / Fiwix

A UNIX-like kernel for the i386 architecture

dennishilk / boringos

Independent desktop operating system with its own kernel, userspace and native BoringWM, written primarily in C

Mazin-O3 / cpm-neo

A CP/M-inspired operating system

klange / toaruos

Complete, independent operating system built by humans.

DC-SWAT / DreamShell

Operating system for the Sega Dreamcast, NAOMI and NAOMI 2