Meaning – The disk operating system, or DOS, is a computer operating system, that resides on a disk, and can make use of a disk storage device, like a hard drive, optical disk, or even a floppy disk, to store the data.
One of the major requirement of the disk operating system is that it must provide a file system for organizing, reading, and writing files on the storage disk.
DOS was the first operating system used on IBM powered PCs. It was available in two versions –
PC-DOS was the version developed by IBM and sold to the first IBM-compatible manufacturers.
MS-DOS was the version that Microsoft bought the rights to, and was bundled with the first versions of Windows.