minix.rs

MINIX 3, in Rust, for the 64-bit era

A 64-bit-only reimplementation of MINIX 3 in Rust, preserving the original ABI.

minix.rs is a learning operating system built around a greenfield Rust microkernel. It keeps MINIX 3’s architecture — message-passing IPC, user-space servers, user-space drivers, and a fine-grained privilege model — while dropping 32-bit legacy and targeting modern 64-bit platforms under QEMU.

Highlights

• Microkernel in Rust (no_std, no_main) — only IPC, scheduling, interrupt dispatch, and memory protection live in the kernel.
• Message passing — MINIX 3’s six IPC primitives; five are live (SEND, RECEIVE, SENDREC, NOTIFY, SENDNB), SENDA is still a stub.
• User-space servers — PM, VFS, VM, RS, DS, SCHED run as separate processes.
• User-space drivers — VirtIO drivers as separate processes (planned; see the Roadmap).
• aarch64 first (Apple Silicon / QEMU virt); x86_64 planned.
• ABI-preserving — message layout, endpoints, and call numbers track MINIX 3.

Status

Phases 0–4 are complete (as of 2026-07-18): the aarch64 kernel boots through UEFI/Limine, the system servers (PM, VFS, VM, RS, DS, SCHED) start from a multi-module boot image and discover each other via DS, and init (PID 1) drives a fork/exec/wait loop over a boot-embedded worker binary — all verified in QEMU. Phase 5 — a musl libc fork and the first file systems, ending in a C “Hello World” — is next; the working plan lives in the repository’s docs/plan.md.

About this book

This book is the canonical, source-derived documentation for minix.rs, written from the actual kernel and server code. Chapters describe the system in the present tense only for what boots today; forward-looking design is collected in the Roadmap.

Note: The repository’s docs/ directory once held hand-written bootstrap notes used to plan the project; those have been ported into this book and retired. Only the planning tree remains there — docs/plan.md (the live phase tracker) and docs/plans/ (per-phase slice histories).