Modus‑Lisp

What moved, across every repository in the workspace, and why it was hard. Every claim comes out of the commit log, and where one reaches outside it the method note at the foot of the issue says so — along with what was measured and what was left out. Numbering runs from the project's first working week, so № 1 is in March 2025 and the count is the number of weeks that have had commits in them. Every week of the project has an issue.

Latest

1. № 25
   29 Aug 26 The Pi Zero answers the doorbell A real OpenSSH client logs in to bare-metal Modus on Pi Zero 2 W silicon, then downloads a library and runs it — and the desktop above it learns its own name and its own resolution. 97 commits.
2. № 24
   22 Aug 26 The stack learns to leave home kiln and glass-sdl appear, the CL stack runs a REPL on real Pi Zero silicon, one HTTP client replaces four, and half a dozen repos stop assuming whose home directory they are in. 136 commits.
3. № 23
   15 Aug 26 Two packages, one variable Nine of Modus's name-keyed registries turn out to be blind to packages, one of them mis-dispatching in silence; the build starts checking itself; and alexandria finishes at 230/230. 273 commits.
4. № 22
   8 Aug 26 Speech, both ways A text-to-speech engine, a speech recognizer, and a desktop that types what it hears into whichever window has focus. Underneath, the JIT stops falling back to the interpreter. 218 commits.
5. № 21
   1 Aug 26 629 bytes of desktop A VP8 encoder written from the RFC goes from its first entropy coder to Safari decoding a live Lisp desktop, in twenty-three hours. Also a PDF renderer, three audio decoders, and Acid3 at 100/100. 294 commits.

From the beginning

1. № 4
   14 Mar 26 The Fixpoint of Theseus Five SHA-256 comparisons prove the compiler leaves no fingerprint of the machine that ran it: a 32-bit image builds a 64-bit one bit-identical to the 64-bit build. Then Movitz is deleted. 3 commits.
2. № 3
   7 Mar 26 A Pi with no SD card Modus leaves the emulator: real Pi Zero 2 W silicon, booted over USB, reached by SSH across a USB Ethernet gadget it implements itself. The compiler compiles its own 759 functions. 3 commits.
3. № 2
   28 Feb 26 Nine architectures in four commits Work resumes after eleven months, and not where it stopped. A 64-bit rewrite with actors and SMP, a kernel that recompiles itself from source it carries inside, and a portable bytecode ISA with nine backends. 4 commits.
4. № 1
   15 Mar 25 A quick hack, on Movitz The first commit is a prototype: 29,000 lines of Modus on 55,000 lines of somebody else's bare-metal Lisp, booting under QEMU into a REPL with TLS and SSH. It was built in silence, shelved for eleven months, and its date hides a fortnight of work that happened in 2026. 1 commit.

The full archive — every issue back to March 2025 →

1. note
   30 Aug 26 The floor does not compound Twenty-six weeks, measured. Output peaked in July and has halved since, which is not a slowdown — and the one repository that never accelerated is the one underneath all the others.

• The compiler leaves no fingerprint of the machine that ran it. A 32-bit image builds a 64-bit one that is bit-identical to the 64-bit build's, checked by five SHA-256 comparisons across three architectures — № 4. The whole self-hosting loop runs with no host Lisp in it at all — № 20.
• Nothing is graded by the thing that wrote it. The Common Lisp is measured against a conformance suite written by somebody with no stake in it, through a harness rebuilt after it was caught losing 17,587 tests in silence (№ 6). Fonts are checked against ttx and HarfBuzz, the Bitcoin engine against Bitcoin Core's own compiled library at zero divergence (№ 15), the video encoder against libvpx, the SVG renderer against Chromium. New libraries build the oracle before they build the feature (№ 17).
• One C library, in one file. Putting pixels on a hosted operating system's screen means asking its window server, so glass-sdl binds libSDL2 — and that is the only third-party native library the workspace links, alongside two POSIX calls where a hosted Lisp has to ask the host. The other foreign code in the tree is oracles: Core's library, Chromium, ffmpeg, linked so the implementations can be told they are wrong.

Legibility is the argument this project makes about software, so it would be strange to make the archive itself awkward to read. Every issue has a Markdown mirror at its own address with index.md on the end — same text, no chrome. The rest is where a machine would look for it:

• /feed.xml — Atom, one entry per issue, each pointing at both the page and its Markdown.
• /llms.txt — the whole archive as one annotated index, in the llms.txt convention.
• /index.json — the ledger: every issue with its number, date span, commit count, repositories touched, and both URLs.
• /sitemap.xml and /robots.txt — crawlable, and explicitly welcome to be.

None of it is written by hand. bin/mirror reads the site's own HTML back and regenerates the lot, so the mirrors cannot drift from the pages they mirror; bin/mirror --check fails if they have.

Each piece is a library in its own right, clean-room and in portable Common Lisp, and each is used by something else here rather than written to be admired. They are grouped by what they are for; the dependencies run mostly downward, and occasionally sideways in ways worth noticing — the B-tree under the Bitcoin node is also the B-tree under the filesystem that a git repository lives in.