# froggey/Mezzano

An operating system written in Common Lisp

Repository: https://github.com/froggey/Mezzano
Canonical: https://ross.abutalabs.com/products/mezzano
Language: Common Lisp
License: MIT
License Family: permissive
Last push: 2026-08-16T12:25:41+00:00

## Health v2 (maintenance only)
Score: 67/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 98, release rhythm 8, longevity 100
- inputs: {"age_days": 4236, "days_push": 17, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3887, forks 203 (observed 2026-08-28T04:08:28.273738+00:00)

## What it is
Mezzano is an operating system written entirely in Common Lisp, featuring its own compiler, GUI, networking stack, and file system support. It runs on x86-64 hardware and in emulators like VirtualBox and QEMU, with experimental AArch64 support.

## Use cases
- run a full operating system written in Common Lisp
- experiment with a Lisp-based OS in QEMU or VirtualBox
- study OS internals implemented in a high-level language
- explore a live image with built-in editor, compiler, and REPL
- test SMP, networking, and filesystem support in a Lisp OS
- hack on an operating system kernel from within itself

## When to choose
- you want to use or study a complete OS built in Common Lisp
- you're interested in Lisp machines and image-based development
- you want a self-hosting environment with compiler, editor, and introspection tools
- you're doing research or education on OS design with a high-level language

## When to avoid
- you need a production OS with broad hardware support
- you need guaranteed driver support for specific hardware
- you need a stable, supported platform for daily use
- you're not comfortable digging into source code to get things working

## Facets
- artifact type: application
- maturity: active
- function: interpreter, compiler, gui, networking, file-system
- domain: operating-systems, programming-languages, developer-tools
- platform: cpp, cross-platform
- tags: common-lisp, operating-system, lisp-machine, x86-64, research-os

## Member repositories
- froggey/Mezzano (main) score 67

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:28.273738+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:25:39.371421+00:00, confidence not recorded.
  - readme: https://github.com/froggey/Mezzano (fetched 2026-08-28T04:08:28.273738+00:00, sha ba278e42c68f)
- Data as of 2026-08-30T08:39:29.467469+00:00.