AMSDOS

AMSDOS, short for Amstrad Disk Operating System, is the disk operating system Locomotive Software wrote for the 8-bit Amstrad CPC computer and its clones. It debuted in 1984 on the CPC 464 with its 3-inch disk drive and later shipped on the CPC 664 and CPC 6128, built into ROM and reached through Locomotive BASIC or firmware calls rather than a command shell of its own. Its main job was mapping the CPC's existing cassette access routines onto a disk drive, so that most cassette software ran unmodified from disk, and it could address up to two disk drives at once.