TOS (The Operating System) is the

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

of the Atari ST range of computers. This range includes the 520ST and 1040ST, their STF/M/FM and STE variants and the Mega ST/STE. Later, 32-bit machines ( TT,

Falcon030 The Atari Falcon030 (usually shortened to Atari Falcon), released in 1992, was the final personal computer product from Atari Corporation. A high-end model of the Atari ST line, the machine is based on a Motorola 68030 CPU and a Motorola 56001 di ...

) were developed using a new version of ''TOS'', called

MultiTOS MiNT is Now TOS (MiNT) is a free software alternative operating system kernel for the Atari ST system and its successors. It is a multi-tasking alternative to TOS and MagiC. Together with the free system components fVDI device drivers, XaAES ...

, which allowed multitasking. More recently, users have further developed TOS into

FreeMiNT MiNT is Now TOS (MiNT) is a free software alternative operating system kernel for the Atari ST system and its successors. It is a multi-tasking alternative to TOS and MagiC. Together with the free system components fVDI device drivers, XaAE ...

Details

Atari TOS (The Operating System) debuted with the Atari 520ST in 1985. TOS combines

Digital Research Digital Research, Inc. (DR or DRI) was a company created by Gary Kildall to market and develop his CP/M operating system and related 8-bit, 16-bit and 32-bit systems like MP/M, Concurrent DOS, FlexOS, Multiuser DOS, DOS Plus, DR DOS and Gr ...

GEM A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, a ...

GUI running on top of the

DOS DOS is shorthand for the MS-DOS and IBM PC DOS family of operating systems. DOS may also refer to: Computing * Data over signalling (DoS), multiplexing data onto a signalling channel * Denial-of-service attack (DoS), an attack on a communicat ...

-like GEMDOS. Features include a

flat memory model Flat memory model or linear memory model refers to a memory addressing paradigm in which "memory appears to the program as a single contiguous address space." The CPU can directly (and linearly) address all of the available memory locations witho ...

-compatible disk format (starting with TOS 1.04), support for

MIDI MIDI (; Musical Instrument Digital Interface) is a technical standard that describes a communications protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and ...

, and a variant of SCSI called ACSI in later versions. Atari's TOS is usually run from ROM chips contained in the computer: Thus, before local hard drives were available in home computers, it was an almost instant-running OS. TOS booted off floppy disks in the very first STs, but only about half a year after the ST was introduced, all ST models started shipping with the latest version of TOS in

ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...

. TOS consisted of the following: * Desktop – The main interface loaded after bootup. *

– Graphics Environment Manager, licensed from

** 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. 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 desk accessories to be loaded into the system, which are similar to TSRs (

Terminate and Stay Resident A terminate-and-stay-resident program (commonly TSR) is a computer program running under DOS that uses a system call to return control to DOS as though it has finished, but remains in computer memory so it can be reactivated later. This technique ...

programs) on PCs.

was developed to allow TOS to preemptively multitask.

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 Extension, extend or extended may refer to: Mathematics Logic or set theory * Axiom of extensionality * Extensible cardinal * Extension (model theory) * Extension (predicate logic), the set of tuples of values that satisfy the predicate * E ...

: * *.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

.EXE .exe is a common filename extension denoting an executable file (the main execution point of a computer program) for Microsoft Windows, OS/2, and DOS. File formats There are numerous file formats which may be used by a file with a extensi ...

.COM The domain name .com is a top-level domain (TLD) in the Domain Name System (DNS) of the Internet. Added at the beginning of 1985, its name is derived from the word ''commercial'', indicating its original intended purpose for domains registere ...

running in a

CLI CLI may refer to: Computing * Call Level Interface, an SQL database management API * Command-line interface, of a computer program * Command-line interpreter or command language interpreter; see List of command-line interpreters * CLI (x86 instruc ...

-mode box. The desktop clears the screen, turns on the

text cursor In human–computer interaction, a cursor is an indicator used to show the current position on a computer monitor or other display device that will respond to input from a text input or pointing device. The mouse cursor is also called a Pointer ...

, and hides the

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pointer. * *.TTP – "TOS takes parameters". This opens a

dialog box The dialog box (also called dialogue box (non-U.S. English), message box or simply dialog) is a graphical control element in the form of a small window that communicates information to the user and prompts them for a response. Dialog boxes ar ...

where

arguments An argument is a statement or group of statements called premises intended to determine the degree of truth or acceptability of another statement called conclusion. Arguments can be studied from three main perspectives: the logical, the dialectic ...

can be added for the program. It converts characters to

uppercase Letter case is the distinction between the letters that are in larger uppercase or capitals (or more formally ''majuscule'') and smaller lowercase (or more formally ''minuscule'') in the written representation of certain languages. The writing ...

. * *.GTP – "GEM takes parameters". This opens a

where

can be added for the program. It converts characters to

. 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

FAT12 File Allocation Table (FAT) is a file system developed for personal computers. Originally developed in 1977 for use on floppy disks, it was adapted for use on hard disks and other devices. It is often supported for compatibility reasons by ...

(or, on hard disks,

FAT16 File Allocation Table (FAT) is a file system developed for personal computers. Originally developed in 1977 for use on floppy disks, it was adapted for use on hard disks and other devices. It is often supported for compatibility reasons by ...

) file system.alternative-system.com - Revive GEMDOS for lisa
/ref> The major differences are the fact that the boot sector does not need to contain the IBM compatible jump sequence at the beginning (typically or ), the lack (before TOS 1.04) of an OEM identifier compatible with PC-based systems, and the fact that a checksum is used to mark the boot sector as executable (the PC format uses the signature word instead). Executable boot sectors for the Atari platform typically start with an MC68K jump opcode (e.g. , and the last two byte word must sum with the rest of the boot sector (in big-endian word form) to in order to be bootable. 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

Windows 9x Windows 9x is a generic term referring to a series of Microsoft Windows computer operating systems produced from 1995 to 2000, which were based on the Windows 95 kernel and its underlying foundation of MS-DOS, both of which were updated in su ...

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

Blitter A blitter is a circuit, sometimes as a coprocessor or a logic block on a microprocessor, dedicated to the rapid movement and modification of data within a computer's memory. A blitter can copy large quantities of data from one memory area to ano ...

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

TOS 2

* 2.02 Early TOS release for Mega STE. * 2.05 (Mega STE TOS) Only found in the Mega STE with 720K floppy drive. ** Format: 2 chip ROMs (256 KB) ** ROM date: 5 December 1990 ** Machines: Mega STE * 2.06 (ST/STE TOS) Last TOS version for ST/STE computers. Bug fixes, 1.44 MB disk support, memory test. Adds GTP program support (GEM-Takes-Parameters). Greatly enhanced GEM GUI. IDE hard disk booting. Atari logo display at boot-up. Automatic cold boot memory test. Supports higher resolutions. ** Format: 2 chip ROMs (256 KB) ** ROM date: 14 November 1991 ** Machines: 520ST, 1040ST, 520STE, 1040STE * 2.07 used on the Falcon prototype "FX-1" * 2.08 used in notebook ST. ROM also contains some notebook-specific utilities: STTRANS (null-modem/ parallel-cable data transfer), power management tools, hard disk drive tools and drivers (AHDI, XHDI, BOOKINST and BOOKFMT) and a RAMdisk installer.

TOS 3

* 3.01, 3.05, 3.06 (TT TOS) Primarily for 68030 TT support only. Supports fast "TT RAM", special TT screen resolutions etc. ST-hardware-compatible "Line-A" API dropped for extended TT functionality, forcing programmers to use GEM-compliant VDI calls etc. and thus encouraging GEM-compatible (as opposed to ST-compatible) development. ** Format: 4 chip ROMs (512 KB)

TOS 4

* 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.

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

– User's guide {{Disk operating systems Atari operating systems TOS Disk operating systems Discontinued operating systems Window-based operating systems 1985 software