Redox OS — Unix-Like Operating System Written in Rust

Introduction

Redox is a Unix-like microkernel operating system written almost entirely in Rust. It applies Rust's memory safety and ownership model at the OS level, eliminating entire classes of bugs such as buffer overflows and use-after-free that plague traditional C-based operating systems.

What Redox OS Does

• Provides a complete microkernel OS with drivers, filesystem, and networking
• Enforces memory safety throughout the kernel and userspace using Rust
• Implements a POSIX-compatible API layer for running existing Unix software
• Isolates drivers and services in userspace to limit crash impact
• Offers a custom GUI (Orbital) and package manager (pkgutils)

Architecture Overview

Redox uses a true microkernel design where the kernel handles only scheduling, memory management, and IPC. Device drivers, filesystems, and network stacks run as userspace processes communicating through URL-scheme-based message passing. This architecture means a faulty driver cannot crash the kernel. The system call interface is minimal, with most functionality accessed through scheme-based file descriptors.

Self-Hosting & Configuration

• Build requires Rust nightly toolchain and cross-compilation tools
• Supports x86_64 as the primary target architecture
• Configuration through filesystem.toml for selecting included packages
• Runs on real hardware (limited driver support) and in VMs via QEMU/VirtualBox
• Package recipes define how to cross-compile software for Redox

Key Features

• True microkernel with all drivers in userspace for reliability
• Written in Rust for memory safety without garbage collection overhead
• URL-based scheme system unifies access to resources (files, devices, network)
• Custom C library (relibc) written in Rust with POSIX compatibility
• Boots on select real hardware including Thinkpad and Framework laptops

Comparison with Similar Tools

• Linux — Monolithic C kernel; Redox is a microkernel in Rust with stronger isolation
• seL4 — Formally verified microkernel; Redox focuses on practicality and POSIX compat
• Fuchsia — Google's capability-based OS; Redox targets desktop Unix workflows
• Hubris — Oxide's embedded Rust OS; Redox targets general-purpose computing
• Managarm — Async microkernel; Redox has broader hardware support and packaging

FAQ

Q: Can I run Linux applications on Redox? A: Many POSIX applications compile and run on Redox via relibc. Full Linux binary compatibility is not supported.

Q: Is Redox ready for daily use? A: Not yet. Redox is a research and development OS with growing but limited hardware and software support.

Q: Why a microkernel instead of monolithic? A: Microkernels isolate faults — a driver crash does not bring down the system. Combined with Rust, this provides defense in depth.

Q: What architectures are supported? A: x86_64 is the primary target. ARM64 support is in progress.

Sources

• https://gitlab.redox-os.org/redox-os/redox
• https://www.redox-os.org/