Web site: (not active)
Desktop environment: GEM
Architecture: Motorola 86000
Based on: Independent
Wikipedia: Atari TOS
Media: Live Floppy
The last version | Released: 4.92 | June 22, 1993
Atari TOS – an operating system of Atari ST, Mega ST, STE, Mega STE, TT030, Falcon computers and their clones: Direct, Medusa, Hades, Milan. Unlike other systems, TOS is not installed on the hard disk, but is stored in the ROM.
The first version of TOS, the so-called preTOS booted from a floppy disk, all subsequent ones were already in ROM memory installed directly inside the computer. Versions from 1.0 to 1.04 were placed in chips with a capacity of 192KB, from 1.6 to 2.06 – with a capacity of 256KB, and later versions – 512KB.
TOS was offered in multiple languages. Up to version 4.01, to change the language version, it was necessary to replace the entire ROM module. From version 4.01 you do not need to change the module, because it already contains seven language versions.
Each TOS contains version-specific AES and GEMDOS.
AES (Application Environment Services) is the superior part of GEM responsible for handling applications, windows, menus, sending messages between applications, handling objects defined in the RSC file, etc. It is a system layer of a higher order than VDI, hardware independent.
The TOS system consists of the following parts:
– BIOS – responsible for block and hardware-dependent operations,
– XBIOS – (Extended Basic Input/Output System) extended part of the BIOS, responsible for hardware support.
– LineA – responsible for basic graphics operations, together with BIOS and XBIOS, constitute the lowest logical layer of the TOS system
– GEMDOS – (GEM Disk Operating System) responsible for operations on files and memory,
– VT52 – terminal emulator in VT-52 standard
– GEM – (Graphic Environment Manager) GUI graphical environment divided into the following parts:
— VDI – (Virtual Device Interface) responsible for direct access to the device and drawing basic graphic objects and characters
— AES – (Application Environment Services) responsible for the window and GUI.
— GEM Desktop – graphical system shell
Later, extensions were created that added new functions, loaded from the disk:
– AHDI – (Atari Hard Disk Interface) hard disk driver
– XHDI – (eXtended Hard Disk Interface)
– GDOS – (Graphics Device Operating System) responsible for handling printers as well as vector fonts
– GDPS – scanner driver protocol
– MetaDOS – responsible for CD-ROM support
– BigDos replacement for the GEMDOS file system
– XControl – (Extensible Control Panel)
The Atari TOS screenshot source: Wikipedia, author: MJaap; License: Creative Commons Attribution-Share Alike 4.0 International.