The first tools that analyzed and extracted data from floppy disks and hard disks were MS-DOS tools for IBM PC file systems. A file system is a structured representation of data and a set of metadata describing this data. The file system of the IBM supports stream input/output and storage management, providing a structure over all information stored in the system. A floppy disk consists of a thin plastic disk coated with magnetic material (it was designed by IBM in the early 1970s). A hard disk is fixed on the system unit. It is made up of several circular disks called platters. MS-DOS (Microsoft Disk Operating System) is a licensed operating system for use on microcomputers from various manufacturers.