TOS is the operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

 of the Atari

Atari

Atari is a corporate and brand name owned by several entities since its inception in 1972. It is currently owned by Atari Interactive, a wholly owned subsidiary of the French publisher Atari, SA . The original Atari, Inc. was founded in 1972 by Nolan Bushnell and Ted Dabney. It was a pioneer in...

 ST

Atari ST

The Atari ST is a home/personal computer that was released by Atari Corporation in 1985 and commercially available from that summer into the early 1990s. The "ST" officially stands for "Sixteen/Thirty-two", which referred to the Motorola 68000's 16-bit external bus and 32-bit internals...

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

Atari TT030

-History:Atari Corporation realized that to remain competitive, they needed to begin taking steps to exploit the power offered by other processors in the Motorola 68000 series. At that time, the best option was the 68020. It was the first true "thirty-two bit bus/thirty-two bit instruction" chip...

, Falcon030

Atari Falcon

The Atari Falcon030 Computer System was Atari Corporation's final computer product. Codenamed Sparrow, the machine was based on a Motorola 68030 main CPU, and had a Motorola 56000 digital signal processor, a feature which distinguished it from most other microcomputers of the era.-History:The...

) were developed using a new version of TOS, called MultiTOS, which allowed multitasking

Computer multitasking

In computing, multitasking is a method where multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for...

. More recently, users have developed TOS further into FreeMiNT

MiNT

MiNT is a free software alternative operating system kernel for the Atari ST and its successors. Together with the free system components fVDI , XaAES , and TeraDesk , MiNT provides a free TOS compatible replacement OS that is capable of multitasking.MiNT was originally released by Eric Smith as...

.

Details

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

Digital Research

Digital Research, Inc. was the company created by Dr. Gary Kildall to market and develop his CP/M operating system and related products. It was the first large software company in the microcomputer world...

's GEM

Graphical Environment Manager

GEM was a windowing system created by Digital Research, Inc. for use with the CP/M operating system on the Intel 8088 and Motorola 68000 microprocessors...

 GUI running on top of the DOS

DOS

DOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.Related...

-like GEMDOS. Features include a flat memory model

Flat memory model

Flat memory model or linear memory model refers to a memory addressing paradigm in low-level software design such that the CPU can directly address all of the available memory locations without having to resort to any sort of memory segmentation or paging schemes.Memory management and...

, MS-DOS

MS-DOS

MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...

-compatible disk format, support for MIDI, and a variant of SCSI

SCSI

Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...

 called ACSI in later versions. Atari's TOS is 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 originally booted off floppy disks, but later ST models came with the latest version of TOS in ROM

Read-only memory

Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...

.

TOS consisted of the following:

• Desktop - The main interface loaded after bootup.
• GEM
  Graphical Environment Manager
  GEM was a windowing system created by Digital Research, Inc. for use with the CP/M operating system on the Intel 8088 and Motorola 68000 microprocessors...
  
   - Graphical Environment Manager, licensed from Digital Research
  Digital Research
  Digital Research, Inc. was the company created by Dr. Gary Kildall to market and develop his CP/M operating system and related products. It was the first large software company in the microcomputer world...
  
  
  • 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 - Xtended BIOS
• Line-A - Low-level high-speed graphics calls. Obsolete

The following were extensions to TOS (loaded separately):

• GDOS - Graphics Device Operation System
• AHDI - Atari Hard Disk Interface (driver for Hard Drive)

True multitasking was not directly supported, TOS allows desk accessories to be loaded into the system which are similar to TSRs (Terminate and Stay Resident

Terminate and Stay Resident

Terminate and Stay Resident is a computer system call in DOS computer operating systems that returns control to the system as if the program has quit, but keeps the program in memory...

) on PCs (up to a maximum of six) and could co-operatively multitask. MultiTOS 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

Executable

In computing, an executable file causes a computer "to perform indicated tasks according to encoded instructions," as opposed to a data file that must be parsed by a program to be meaningful. These instructions are traditionally machine code instructions for a physical CPU...

 files are identified by their extensions

Filename extension

A filename extension is a suffix to the name of a computer file applied to indicate the encoding of its contents or usage....

:

• *.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 or .COM running in a CLI-mode box. The desktop clears the screen, turns on the text cursor
  Cursor (computers)
  In computing, a cursor is an indicator used to show the position on a computer monitor or other display device that will respond to input from a text input or pointing device. The flashing text cursor may be referred to as a caret in some cases...
  
  , and hides the mouse
  Mouse (computing)
  In computing, a mouse is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user's hands, with one or more buttons...
  
   pointer.
• *.TTP - "TOS takes parameters". This opens a dialog box
  Dialog box
  In a graphical user interface of computers, a dialog box is a type of window used to enable reciprocal communication or "dialog" between a computer and its user. It may communicate information to the user, prompt the user for a response, or both...
  
   where arguments
  Parameter (computer science)
  In computer programming, a parameter is a special kind of variable, used in a subroutine to refer to one of the pieces of data provided as input to the subroutine. These pieces of data are called arguments...
  
   can be added for the program. However, 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 uses GEMDOS which uses a modified FAT 12

File Allocation Table

File Allocation Table is a computer file system architecture now widely used on many computer systems and most memory cards, such as those used with digital cameras. FAT file systems are commonly found on floppy disks, flash memory cards, digital cameras, and many other portable devices because of...

 file system. The major differences are FAT size of 5 sectors instead required 3 on floppy discs, extended size of using 10 sectors per track instead of with 9 sectors per track for floppy discs and 0xE9 on boot sector start from TOS v1.04.

Discs formatted using MS-DOS

MS-DOS

MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...

 can be used with GEMDOS, but not vice versa.
GEMDOS disc file systems can be read using MS-DOS

MS-DOS

MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...

 or MS-Windows 95

Windows 95

Windows 95 is a consumer-oriented graphical user interface-based operating system. It was released on August 24, 1995 by Microsoft, and was a significant progression from the company's previous Windows products...

. Later systems from Microsoft have incompatibilities.

CP/M

CP/M

CP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...

 was considered originally but Atari

Atari

Atari is a corporate and brand name owned by several entities since its inception in 1972. It is currently owned by Atari Interactive, a wholly owned subsidiary of the French publisher Atari, SA . The original Atari, Inc. was founded in 1972 by Nolan Bushnell and Ted Dabney. It was a pioneer in...

 went with GEM

Graphical Environment Manager

GEM was a windowing system created by Digital Research, Inc. for use with the CP/M operating system on the Intel 8088 and Motorola 68000 microprocessors...

 instead. So there are roots both in CP/M and MS-DOS.

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
    Kilobyte
    The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
    
    )
  • Rom date: 20 Nov 1985
  • Machines: 520ST, 1040ST
• 1.02 (MEGA TOS) fixed bugs, supported Blitter
  Blitter
  In a computer system, a blitter is a circuit, sometimes as a coprocessor or a logic block on a microprocessor, that is dedicated to the rapid movement and modification of data within that computer's memory...
  
   co-processor and real-time clock.
  • Formats: 2 chip and 6 chip ROMs (192 KB)
  • Rom date: 22 Apr 1987
  • Machines: 520ST, 1040ST, 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 Apr 1989
  • Machines: 520ST, 1040ST, 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 Jul 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 Jan 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 Dec 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 Nov 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, 16MHz 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.
• 4.9x (4.92, 4.98) Were developed by Atari as bug-ridden internal developer version, but never officially released. Though sometimes are offered for download, the distribution is illegal.

TOS 4 ROM contains five, user-selectable language versions.

See also

• EmuTOS
  EmuTOS
  EmuTOS is a replacement for TOS , released as free software. It does not add any functionality and is mainly intended to be used with Atari emulators, such as Hatari...
  
  
• Multitasking versions of TOS
  • MiNT
    MiNT
    MiNT is a free software alternative operating system kernel for the Atari ST and its successors. Together with the free system components fVDI , XaAES , and TeraDesk , MiNT provides a free TOS compatible replacement OS that is capable of multitasking.MiNT was originally released by Eric Smith as...
    
    
  • MagiC
    MagiC
    MagiC is a third party multitasking-capable TOS-compatible operating system for the Atari ST range of computers, including some newer clone machines...
    
    
  • MultiTOS
• GEM
  Graphical Environment Manager
  GEM was a windowing system created by Digital Research, Inc. for use with the CP/M operating system on the Intel 8088 and Motorola 68000 microprocessors...
  
  

External links

• tos.hyp - a reference about the system api of TOS, MultiTOS, MagiC and MagiCMac
• Town's Guide to TOS Revisions
• Atari ST System Disks
• TOS 2.06 Guide - User's guide
• Atari Compendium - Reference guide for Atari ST programming. Recommended