DISK OPERATING SYSTEM

DOS (Disk Operating System)

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Disk Operating System (DOS)

In the 1980s or early 1990s, the operating system that shipped with most PCs was a version of the Disk Operating System (DOS)created by Microsoft: MS-DOS.
MS-DOS is a disk operating system for IBM PC–compatible computers.
In its day, it was easily the most popularoperating system in the world.

 INTERNAL COMMAND

1)Dir
2)Rename (Ren)
3)Delete (Del)
4)Copy
5)Type
6)Set Attributes (attrib)

DOS has a way of showing which diskdrive is currently active. The floppy disk drives are assigned alphabets Aand B, whereas the hard disk driveis assigned the alphabet C.
Ex: If your PC includes a hard disk, besides a FDD (Floppy Disk Drive), the drive names would be A and C. If the prompt is A then it implies that the first floppy disk drive isactive. Where as the DOS prompt would be C, if the hard disk is active. Data as well as instructions reside in a file stored in a disk.

Disk operating system is also used to describe several very similar command line disk operating systems. PC-DOS (Personal Computer Disk Operating System) was the first widely-installed disk operating system used in personal computers running on Intel 8086 16-bit processors. It was developed for IBM by Microsoft Corporation, which also produced its own almost identical version called MS-DOS. Other computers at the time, such as the Commodore 64, Atari 800, and Apple II, all featured a disk operating system, CBM DOS, Atari DOS, and Apple DOS, respectively. (DOS/360 was an operating system for IBM mainframes which first appeared in 1966, but is unrelated to the 8086-based DOS of the 1980s.