In early use, the underlying hardware, rather than the contents stored on it, was denominated a "file". For example, the IBM 350 disk drives were denominated "disk files". The introduction, circa 1961, by the Burroughs MCP and the MIT Compatible Time-Sharing System of the concept of a "file system" that managed several virtual "files" on one storage device is the origin of the contemporary denotation of the word. Although the contemporary "register file" demonstrates the early concept of files, its use has greatly decreased.