AMSDOS is a Disk Operating System that worked on the 8-Bit Amstrad CPC Computer (and various clones). The name is a contraction of Amstrad Disc Operating System.
AMSDOS first appeared in 1984 on the CPC464, with added 3 inch disk drive, and then on the CPC 664 and CPC 6128.
Relatively fast and efficient for its time, AMSDOS was quicker and more effective than most of its contemporaries.