Format (command)
In computing, format is a command-line utility that carries out disk formatting. It is a component of various operating systems, including 86-DOS, MS-DOS, IBM PC DOS and OS/2, Microsoft Windows and ReactOS. == Overview == The command performs the following actions by default on a floppy disk, hard disk drive, solid state (USB), or other magnetic medium (it will not perform these actions on optical media): clearing the FAT entries by changing them to 0x00 clearing the FAT root directory by changing any values found to 0x00 checking each cluster to see if it is good or bad and marking it as good or bad in the FAT Any storage device must have its medium structured to be useful.