The Magnetic Vault is an open-source art and research project. It stores digital things on ordinary cassette tapes — and proves they come back perfectly.
It started as a question: could you store a real computer file — eventually a tiny AI model — on an ordinary audio cassette, and get every bit back? The answer turned out to be yes. So the question became: how far can it go?
Far enough to put DOOM on a tape. The full game — Freedoom Episode 1, all nine maps, in-browser sound, save support, and a hand-built bonus level — was recorded to a real C90, played back through a deck speaker into a phone microphone, and decoded byte-exact. Zero codeword failures out of 9,225. The same cryptographic fingerprint going in and coming out. The HTML off the tape was identical to the file that went on.
Around that result grew a small library, each title chosen to be a little wonder: a ghost story that reads itself aloud, a fantasy games console, a chess engine, fifty-eight classics on a single tape, a Swedish collection. And a tape whose only job is to measure your own cassette deck and tell you what it can do.
Because they're the most ordinary, most human storage medium we ever made. Cheap, warm, physical, a little unreliable — and built to remember. There's a quiet thrill in handing something as abstract as software to a machine that only ever knew music, and watching it keep faith with every bit.
It's not about being practical. It's about the romance of giving a file a body — and the discipline of proving it survived.
Everything is open. The DSP, the modems, the encoder and decoder, the proofs, the tape audio — all public, all permissively licensed where the underlying work allows. You can read exactly how a file becomes sound, run the decoder yourself, and verify the byte-exact claim against the published results. Nothing here asks you to take it on faith.
Every release is free to play and download. What can be ordered as a physical cassette depends on the licence of the work it carries.
Works in the public domain, or under permissive licences — MIT, Apache, GPL, CC-BY-SA — can be ordered as made-to-order cassettes. GPL releases like DOOM ship with their source. These carry a plain licence badge and an Order a cassette button.
A couple of releases carry work under a NonCommercial licence — Cory Doctorow's novels and Peter Watts' Blindsight, among others. They're free to play, download, and keep, and we'll happily press one as a gift — but they are not for sale. Those cards show a Free / gift only badge and no buy button.
We honour the wishes of every author whose work we carry. If you make free-culture work and would like it in the vault, get in touch.
Eight tapes, each free to try in the browser. Find the one you want to hold.