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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: v5.9.180 (KERNEL_VERSION in kernel/core/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/JPEG
Games	DOOM (ring-3 port), Minesweeper, Pong, Snake, Tetris
License	GPL v2

Start here

I want to…	Page
Build it and boot it	Building
Ask a common question	FAQ
Look up a term	Glossary
Fix something that broke	Troubleshooting
Understand the kernel layout	Architecture
Follow what happens at power-on	[[Boot-Process
Read the syscall ABI	Syscalls
Drive the shell	Shell

HOWTO

Task-oriented procedures, each with a worked example, a checklist and a troubleshooting table.

Task	Page
Write a ring-3 program	[[HOWTO-Write-a-userspace-program
Add a system call	[[HOWTO-Add-a-system-call
Add a shell command	[[HOWTO-Add-a-shell-command
Add a GUI application	[[HOWTO-Add-a-GUI-application

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, JPEG	[[Image-Decoders
Device drivers	Drivers
Multi-core support	SMP
Privilege boundaries and hardening	Security
Ring-3 programs and the shared libc	Userspace

Reference

Exhaustive, field-by-field references. Every value is quoted from the source tree.

Topic	Page
All 57 syscalls, man-page style	[[Syscall-Reference
All 104 builtins and 62 ring-3 programs	[[Command-Reference
GDT, IDT, MSRs, PTE bits, I/O ports	[[Hardware-Reference
Network headers, ELF, CPIO, EXT2, TLS, image formats	[[Format-Reference
Every source file, with purpose and size	[[Source-Tree-Reference
process_t, vfs_node_t, window_t field by field	[[Kernel-Data-Structures
Diagnosing faults, boot logs, self-tests	Debugging
Symptom → cause → fix	Troubleshooting
Every release, v1.0.0 → v5.9.180	[[Version-History

Project

Source	https://github.com/kazah-png/nyx-os
Issues	https://github.com/kazah-png/nyx-os/issues
License	GPL v2
Contact	uselessalter on Discord · nyxos@inbox.lv
How to contribute	Contributing
Documentation style	[[Wiki-Conventions

Caution

NyxOS is a hobby operating system built for learning. It is not hardened against hostile input and makes no security guarantees — Security documents exactly what is and is not defended. The TLS stack verifies certificate chains and can refuse a connection in strict mode, but every cryptographic primitive was written from scratch for this project and reviewed by nobody else. Do not trust it with anything that matters.

See also

• Architecture — how the pieces fit together
• FAQ — common questions
• Glossary — terminology

External resources

• NyxOS repository — GitHub
• OSDev Wiki — general OS-development reference
• Intel SDM — the x86_64 architecture manuals