DOS: Disk Operating System

DOS, short for disk operating system, is the family of command-line operating systems that ran personal computers in the 1980s and into the 1990s, before graphical systems became dominant. The best known member was MS-DOS, with closely compatible variants such as PC-DOS and DR-DOS. DOS managed the computer's disks, memory, and devices, and presented the user with a text prompt at which commands were typed, rather than the windows and icons of later systems. It traces its design heritage to the earlier CP/M operating system.

A DOS system organises files on disk in a hierarchy of directories, identifying storage devices by drive letters such as A, C, and D. Users worked through internal commands built into the command interpreter and external utilities supplied as separate programs. Disk-management tools included FDISK for partitioning a hard disk and FORMAT for preparing it, while everyday commands handled copying, listing, and deleting files. Because DOS ran one program at a time and addressed memory directly, applications often interacted closely with the hardware.

A distinctive feature was the batch file, a plain-text file of commands with a .BAT extension that DOS executed in sequence, allowing simple automation and startup scripts such as AUTOEXEC.BAT. Although later versions of Windows moved users to a graphical environment, a DOS-like command shell and many of its conventions, including drive letters and the directory structure, persisted. DOS remains of interest for understanding the foundations of the PC and for running legacy software and utilities.

Frequently asked questions

What does DOS stand for?

DOS stands for disk operating system, reflecting its role in managing the disks and files of early personal computers through a text command line.

What is a batch file?

A batch file is a plain-text file with a .BAT extension containing a list of DOS commands that the system runs in order, used for automating tasks and configuring the computer at startup.

What was FDISK used for?

FDISK was the DOS utility for partitioning a hard disk, dividing it into one or more logical drives before they could be formatted and used.