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NyxOS is a from-scratch x86_64 operating system written in C and assembly — no libc, no third-party kernel code. It boots under QEMU (and on real hardware) into a windowed desktop, runs ring-3 ELF programs preemptively across multiple cores, speaks TCP/IP and TLS 1.2 to the live internet, and ships its own web browser.

Current release: v5.9.86 (KERNEL_VERSION in kernel/kernel.h) · Latest LTS: v5.9.0-LTS

At a glance

Architecture	x86_64 long mode, 4-level paging, higher-half monolithic kernel
Multitasking	Preemptive weighted round-robin — 512 processes, 1024 threads
Multi-core	SMP up to 8 CPUs; user processes run in ring 3 on application processors
Memory	Demand paging, copy-on-write, lazy sbrk, mmap, demand-grown user stacks
Syscalls	57, via syscall/sysret — threads, sockets, poll, mmap, signals
Filesystem	VFS over ramdisk, read/write EXT2, /proc, /dev
Networking	RTL8139 → Ethernet/ARP/IP/ICMP/UDP/TCP → DHCP/DNS/HTTP → TLS 1.2
Cryptography	X25519, P-256, P-384, RSA, ECDSA, AES-GCM, SHA-2, X.509 chain verification
GUI	32-window compositor, 4 workspaces, taskbar, Start menu, 10 desktop apps
Browser	Selene — HTTP/HTTPS, links, forms, tables, tabs, inline PNG/BMP/GIF
Games	DOOM (ring-3 port), Minesweeper, Pong, Snake, Tetris
License	GPL v2

Start here

I want to…	Page
Build it and boot it	Building
Understand the kernel layout	Architecture
Follow what happens at power-on	Boot Process
Read the syscall ABI	Syscalls
Write a ring-3 program	Userspace
Drive the shell	Shell

Subsystems

Area	Page
Physical/virtual memory, heap, slab	Memory Management
Scheduler, processes, threads, signals	Process Management
VFS, EXT2, /proc, /dev	Filesystem
Ethernet through HTTP, BSD sockets	Networking Stack
TLS 1.2 and the crypto primitives	Cryptography and TLS
Compositor, framebuffer, windowing	GUI Subsystem
Built-in desktop apps and games	Desktop Applications
The NyxOS web browser	Selene Browser
DEFLATE, PNG, BMP, GIF	Image Decoders
Device drivers	Drivers
Multi-core support	SMP
Privilege boundaries and hardening	Security
Every release, v1.0.0 → v5.9.86	Version History

Project

• Source: https://github.com/kazah-png/nyx-os
• License: GPL v2
• Contact: uselessalter on Discord · nyxos@inbox.lv

Scope and expectations

NyxOS is a hobby operating system built for learning. It is not hardened against hostile input and makes no security guarantees — Security documents what is and is not defended. The TLS stack verifies certificate chains and can refuse a connection in strict mode, but it has never been audited; do not trust it with anything that matters.