Atari DOS

This article is about the operating system of the Atari 8-bit computers. For the Atari ST's operating system, see Atari TOS. For the MS-DOS compatible operating system of the Atari Portfolio, see DIP DOS.

"MyDOS" redirects here. For the similarly pronounced Microsoft operating system, see MIDAS.

"RealDOS" redirects here. For the similarly named successor to Multiuser DOS, see IMS REAL/32.

"Turbo-DOS" redirects here. For the CP/M-compatible operating system, see Software 2000 TurboDOS.

Atari DOS
Atari DOS version 2.5, main menu
Developer	Atari, Inc., Atari Corporation
Working state	Discontinued
Source model	Closed source
Initial release	1979 (1979)
Latest release	XE 1.0 / 1987 (1987)
Available in	English
Supported platforms	Atari 8-bit computers
Default user interface	Menu
License	Proprietary EULA

Atari DOS is the disk operating system used with the Atari 8-bit computers. Operating system extensions loaded into memory were required in order for an Atari computer to manage files stored on a disk drive. These extensions to the operating system added the disk handler and other file management features.

The most important extension is the disk handler. In Atari DOS 2.0, this was the File Management System (FMS), an implementation of a file system loaded from a floppy disk. This meant at least an additional 32 KB RAM was needed to run with DOS loaded.

It is accessed by typing "DOS" at the BASIC or Assembler/Editor prompt to exit the cartridge, If DOS isn't loaded, on the 400 and 800, this exits to the memo pad, which is a text editor built into the firmware of those computers, or on XL and XE machines, the self test.