Atari TOS

TOS (The Operating System) is the

• Desktop – The main interface loaded after bootup.
• GEM – Graphics Environment Manager, licensed from Digital Research
  • AES – Application Environment Services
  • VDI – Virtual Device Interface (screen drivers only, other drivers loaded using GDOS)
• GEMDOS – GEM Disk Operating System
• BIOS – Basic Input/Output System
• XBIOS – Extended BIOS
• Line-A – Low-level high-speed graphics calls. Obsolete from TOS 3 onwards.

The following were extensions to TOS (loaded separately):

• GDOS – Graphics Device Operating System
• AHDI – Atari Hard Disk Interface (hard disk driver)

True multitasking was not directly supported, but TOS allowed up to six

Desktop

The TOS desktop uses icons to represent files and devices, windows and dialog boxes to display info. The desktop file "DESKTOP.INF" was read to determine window settings, icon placements and drive icons, otherwise the standard default desktop of two floppy icons and the trash icon was used.

Later versions use "NEWDESK.INF" for saving and reading the desktop configuration.

Executable files are identified by their extensions:

• *.ACC – Desktop accessory. Automatically loaded.
• *.APP – Application (rarely encountered).
• *.PRG – Executable program. Can be GEM programs.
• *.TOS – "TOS" program that doesn't use GEM — i.e., similar to a PC's
  mouse
  pointer.
• *.TTP – "TOS takes parameters". This opens a
  uppercase
  .
• *.GTP – "GEM takes parameters". This opens a dialog box where arguments can be added for the program. It converts characters to uppercase.

TOS programs (but not GEM programs) can auto boot by placing them in a folder named "AUTO". TOS 1.4 allows GEM programs to be set to load automatically from the "Install Application" dialog. Programs with *.TTP extensions and environments can not be used for auto boot. Desktop accessories were placed in the root directory of the default drive and loaded automatically.

File system

Atari TOS is based on GEMDOS which uses a modified

Unlike MS-DOS, GEMDOS would typically allow disks with unusual sector and track counts, so disks with 10 or even 11 sectors per track and over 80 formatted tracks were not uncommon in the Atari community. Typically a safe combination, such as 10 sectors per track by 80 tracks, was used, yielding an unformatted capacity of 800KB, but many users pushed the capacity of their double-density disks beyond 900KB using custom formats.

GEMDOS disc file systems can be read using DOS or Windows 9x.

Versions

TOS 1

• 1.0 (ROM TOS) Earliest version released on disk. First ROM release of TOS.
  • Formats: floppy, 2 chip and 6 chip ROMs (192 KB)
  • ROM date: 20 November 1985
  • Machines: 520ST, 1040ST
• 1.02 (MEGA TOS) fixed bugs, supported
  co-processor and real-time clock
  .
  • Formats: 2 chip and 6 chip ROMs (192 KB)
  • ROM date: 22 April 1987
  • Machines: 520ST, 1040ST, Mega 1, Mega 2, Mega 4
• 1.04 (RAINBOW TOS) Many bug fixes, file selector changed, DOS-compatible disk formatting, much improved performance. However, compatibility problems with older software.
  • Formats: 2 chip and 6 chip ROMs (192 KB)
  • ROM date: 6 April 1989
  • Machines: 520ST, 1040ST, Mega 1, Mega 2, Mega 4, Stacy
• 1.06 (STE TOS, Revision 1) Support for STe machines only. Needed STE_FIX.PRG to patch bugs.
  • Format: 2 chip ROMs (256 KB)
  • ROM date: 29 July 1989
  • Machines: 520STE, 1040 STE
• 1.62 (STE TOS, Revision 2) bug fixes for the previous 1.06 STE TOS.
  • Format: 2 chip ROMs (256 KB)
  • ROM date: 1 January 1990
  • Machines: 520STE, 1040 STE

• 4.00, 4.01, 4.02, 4.04 (512 KB) Update for Falcon 030 machines only. 68030 only. Adds support for DSP, 16 MHz blitter and video overlay. New v3.40 AES (last single-tasking version, but MiNT/MultiTOS-multitasking-aware) supports: pop-up menus, 3D window and dialog objects (later modified to use more compatible ob_state flags instead of extended type), 256-colour "animated" icons, soft-loaded fonts, inter-app drag&drop, background window manipulation, extensible filesystems. New CPX module for international localisation configuration. V4.04 was the last official Atari version of TOS.
• 4.08 (512 KB) Developed and released by Milan Computersysteme for the Milan, a 68040/60 TOS/GEM computer.
• 4.9x (4.92, 4.98) Never officially released, though prototypes were leaked and subsequently shared.

TOS 4.92 was a version of MultiTOS, the multitasking version of TOS, in a format (.IMG) designed to be written to a ROM chip. TOS 4 ROM contains five user-selectable language versions.

EmuTOS

EmuTOS is a replacement for TOS (the operating system of the Atari ST and its successors), released as a free software.^[4] It runs on Atari and Amiga hardware and various emulators.^[5] Its compatibility with computer video games for Atari ST is limited.^[6]

See also

illegal instruction has been detected

"Row of mushroom clouds" error screen in TOS version 1.0 – 20 bombs denotes that an unspecified error has occurred

• Row of bombs – a system used by TOS to display error messages as one or more rows of bombs, the exact number of bombs denoting an error specified in the manual; version 1.0 used mushroom clouds
  instead
• Multitasking versions of TOS
  • MiNT
  • MagiC
  • MultiTOS
• GEM
• Atari ST character set

References

External links

• tos.hyp - a reference about the system api of TOS, MultiTOS, MagiC and MagiCMac
• Town's Guide to TOS Revisions
• ATARIworld Atari ST System Disks
• ATARI Document Archive
• TOS 2.06 Guide – User's guide