Disk operating system
Disk Operating System (specifically) and disk operating system (generically), most often reveal themselves in abbreviated form as DOS, refer to an operating system software used in most computers that provides the abstraction and management of secondary storage devices and the information on them (e.g., file systems for organizing files of all sorts). Such software is referred to as a disk operating system when the storage devices it manages are made of rotating platters, such as floppy disks or hard disk drives.