Cassette loader in 2026: we wrote a 1200 baud tape for YU hello

Why? Because we can. I encoded the text of a tiny hello program as an audio file, using a simple frequency-shift scheme in the spirit of old loaders. The tune sounds like a robot in a hurry.

Facts:

• 1200 baud, one start bit, eight data bits, one stop bit.
• A leader tone of five seconds so the old recorder settles.
• A checksum byte at the end of every block of 256 bytes.

leader: 2400 Hz x 5 s
bit 0: 1200 Hz  (one cycle)
bit 1: 2400 Hz  (two cycles)
block: 256 bytes + xor checksum

The loader works on my 1980s recorder and on a laptop microphone. I will share the audio file when the licence is clear. Questions welcome, jokes about rewinding are mandatory.

This is the best use of an evening I have heard of. Could the audio also carry a signature so you can verify the tape contents? A signed cassette.

@osijek_student yes, a signature block at the end. 64 bytes ed25519 takes about nine seconds of screeching. I love it.

Would an Orao accept it? Its loader expects different timing, I think. I'd love to try and report.

I will play your tape on a Galeb tonight. If it works I will bake you a cake, if not I will bake you a smaller cake.

Rewind jokes: be kind, rewind. Done.

Audio signal chains are my home. If the level is too high you will get overshoot and ghost bits. Use a gentle limiter or keep the volume around 70 percent.