Motor OS
A simple, fast, and secure operating system built for the cloud. Motor OS targets virtualized workloads such as web serving, serverless computing, and edge caching, and avoids the overhead a general-purpose OS carries when it runs inside a VM.
It is written entirely in Rust, from the kernel to the shell, and its system interface is Rust, not C. It runs as an x86-64 KVM guest under QEMU, Cloud Hypervisor, and Firecracker.
A small kernel, everything else in userspace
The kernel does memory, scheduling, and IPC. One userspace process, sys-io, owns the VirtIO devices, the journaling filesystem, and the TCP/IP stack.
Rust's standard library
Programs that use std and do not depend on Unix or Windows APIs cross-compile
and run. Tokio, mio, hyper, axum, rustls, and russh work. The developer image compiles
Rust, C, and C++ natively.
A native networking stack
IPv4 and IPv6, DHCPv4, TCP with CUBIC, SACK, and RACK-TLP, SYN cookies, a DNS resolver service, and configuration from one TOML file.
Capability-based security
Every process carries an immutable capability word. Three roles, System, Interactive, and None, drive filesystem permissions. There is no root account.
A working shell and tools
A POSIX-style shell, a terminal multiplexer, two editors, an SSH server with SFTP, HTTP servers with TLS, and the usual commands: ls, ps, top, ss, ping, free.
A native Rust package manager
Lorry takes a package's Cargo.toml and Cargo.lock unchanged
and aims for byte-identical binaries, but builds offline, from dependencies that were
fetched once, checked, and approved explicitly; build scripts and procedural macros
run only with a recorded grant.
Status
Motor OS is approaching beta quality. Its development started in 2021, and in 2026 it went through weeks of systematic AI-assisted review and hardening, of the networking stack in particular. Networking is considered ready for production use within its supported feature set; the rest of the system is exercised daily by the full test suite, by long soak runs, and by this website, which is served from Motor OS VMs. There has been no independent security audit yet. See What is Motor OS for a detailed list of what works.