Atari ST

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Atari ST
Atari 1040 STF
Manufacturer: Atari Corporation
Main processor : Motorola 68000 @ 8 MHz
Published: 1985
Posted: 1994
Storage: 512 KiB ~ 4 MiB
Operating system: TOS 1.x
Atari 520ST

Atari ST is a series of home and personal computers by Atari Corporation , which was produced from 1985 to 1994. The GEM graphical user interface made the ST series suitable for professional office applications, among other things, and became the standard computer in small and large recording studios due to the standard MIDI interface . The abbreviation “ST” stands for Sixteen / Thirty-Two (16/32), since the main processor used , the Motorola 68000 , has a 16-bit data bus and works internally with 32 bits.

The ST series was an alternative to the much more expensive Apple Macintosh models and was in direct competition with IBM PC-compatible computers and the Amiga series from Commodore .


Atari 1040 STF with monitor SM 124 from 1987

The Atari ST was one of the first popular models with a graphical user interface , the GEM from Digital Research . The main memory size was between 512  KiB (520ST) and 4 MiB (Mega ST4), this number became part of the model name after rounding up (520ST - 512 KiB; 1040ST - 1024 KiB = 1 MiB).

The only exceptions were the 260ST (was delivered with 512 KiB) and the 520ST + (1 MiB). The 260ST should - true to its name - only be delivered with 256 KiB, but in the final phase of development it turned out that 256 KiB would definitely not be enough to operate the computer sensibly with TOS . However, since the advertising had already started, it was delivered with 512 KiB without further ado. As with the first American 520ST, the first 260ST available in Europe had the TOS reloaded from floppy disk, which greatly reduced the size of the available memory. The 260ST was hardly any different from the 520ST. Actually the only difference was that the 520ST brought the TOS in read-only memory (ROM), whereby the first 520ST and ST + were delivered without such memory modules because they were not yet available at the product launch. Retrofitting was also easy on the 260ST, as the base was already there. The original 520ST disappeared from the market just six months after its appearance, followed a year later by the 260ST. In 1989, all STs without floppy disk drives and the 1040STF were discontinued, at the end of 1990 the MegaST and in January 1994 all other devices (at that time the model range consisted of the 1040STFM, 1040STE , MegaSTE and the high-end computers Falcon 030 and TT 030 ).

The concept changes after completion of the development phase can also be seen in the 520ST + model. There was no space for the additional memory modules on the motherboard , so they had to be soldered piggyback by hand onto the memory circuits of the regular assembly. Individual pins ( RAS , CAS ) of these additional circuits were bent upwards and freely wired.

Additional letters indicated further features: "F" in the name indicated an internal floppy disk drive, "M" an HF modulator . “+” Meant a memory expansion (520ST +) or other expansion like the unpublished 1040 STE +. "E" comes from enhanced , these computers were expanded to include a number of functions, for example the ability to reproduce sounds on 2 channels and a color palette expanded to 4096 colors . The models "LST" (Stacy) and "NST" (ST Book) denote portable devices.

Until November 1985 the Atari ST was delivered with the operating system on diskette (TOS 1.0), later models had the operating system built into the read-only memory .

The software emulator CPMZ80 for the Zilog-Z80 main processor and the operating system CP / M 2.2 were supplied free of charge by Atari. This enabled the 8-bit programs for CP / M, such as B. WordStar , dBASE , Microsoft Multiplan , Turbo Pascal and others on which Atari ST will continue to be used, and the documents, databases, sources and data created with these programs can still be used.

The MegaST series had a remote keyboard and a main memory of up to 4 MiB. Hard disk drives were also available (initially with the MFM process and 20 MB) and could be connected directly to the Atari ST ( DMA port, also called ACSI port ( SCSI variant, stands for "Atari Computer System Interface")).

The Atari ST had the option of connecting either a high-resolution black and white or a lower-resolution color screen. The color resolution was 320 × 200 pixels for 16 colors and 640 × 200 pixels for four colors, each from a palette of 512 colors (or 4096 for the STE).

The widespread monochrome monitor SM124 had a resolution of 640 × 400 pixels at a refresh rate of 70 Hz . These were excellent values ​​for the time. In the area of IBM PC-compatible computers there were CGA , HGC and, for particularly expensive computers, EGA , which only offered 640 × 350 pixels and 60 Hz refresh rate. The successor models SM125 and SM14x also displayed 640 × 400 in 70 Hz.

The computer became particularly popular in the CAD or desktop publishing sector, especially when Atari and other manufacturers brought the high-resolution 19 ″ monochrome monitors onto the market. In the German-speaking countries, office applications such as word processing or spreadsheets also predominated . In particular for the natural sciences and for classical philology (ancient Greek, Hebrew, special characters that are critical of the text, transcriptions, etc.), the Signum! a software was available that had almost unique selling points during this time.

In the United States, the ST was mainly used with a color monitor and was more of a game and demo machine (see: Atari ST demo scene ). A built-in MIDI interface made the Atari ST widely used by musicians and recording studios around the world . This also included Mike Oldfield , who mainly used the Atari ST for the arrangements of his songs. On the album Earth Moving , the use of the Atari ST was stated on the back of the cover. Also Depeche Mode and Fleetwood Mac used the ST at this time. In addition, the Atari ST was, so to speak, a mediator between the worlds. The file system of the floppy disks was largely compatible with that of MS-DOS , so that, for example, one had access to text files that were created on a PC. There was also a Apple - emulator and a CP / M and Z80 emulator, and he was - provided with appropriate software - as an intelligent terminal and developer station at various mainframes and mini-computers from Hewlett-Packard and workstations from Texas Instruments and Hewlett -Packard used. What was remarkable about the operating system of the ST family was the variety of interfaces provided. From the beginning, the connection of graphics tablets and cameras was intended, which was unique at the time, especially since the corresponding hardware was not available on the market at all.

The Atari ST was for three times as expensive in 1984 Apple Macintosh affordable for broad masses Alternative and was in competition for a little later on the market have come Amiga from Commodore .

Several specialist journals such as ST-Computer , ST-Format , ST Magazin , TOS , XEST , ATOS , 68000er or Atari Inside provided users with information on this computer.


  • Main processor: Motorola MC68000 , 8 MHz (Mega STE: 16 MHz)
  • RAM: 512 KiB to 4 MiB (factory equipment, memory expansion by other providers up to 16 MiB possible - but with considerable effort), managed by the memory controller chip "MMU" ( Memory Management Unit ).
  • Graphics chip: “Shifter”, used a freely selectable part of the main memory as image memory , is nowadays referred to as “ shared memory ” architecture. For resolutions and color depths see above. The memory access is completely interlinked with the CPU and the other blocks so that the shifter does not slow down the other blocks when accessing the memory.
  • Bit-blit chip ("Blitter", only from MegaST and STE series, later 1040STFM models were also equipped with bit blit): Support of the main processor in graphics and memory operations. Retrofitting with additional cards possible in all ST models.
  • GLUE chip: system logic that holds the system together (chip selects, clock, etc.)
  • Sound: Yamaha YM-2149 or GI AY-3-8910 , three-part synthesizer chip with noise generator
  • Floppy disk controller WD1772: MFM controller for drives with standard Shugart bus ; newer TT030 and Mega STE as well as all Falcon 030s were delivered with HD disk drives and the fully compatible AJAX, which also runs stably at higher clock frequencies (16 MHz and 32 MHz).
  • DMA controller from Atari controls the ACSI interface (Atari Computer System Interface). ACSI is a SCSI interface that is restricted to group 1 commands and a few signals .
  • 2 Motorola 6850 interface modules, called " ACIA ": 1 for the MIDI interface, 1 for serial communication with the keyboard
  • MFP: 68901 MFP (MultiFunctionPeripheral) u. a. for extended interrupt logic and serial interface
  • Mass storage: built-in floppy disk drive (3½ ″ DD 720 KB) - only for 520 / 1040STF / STFM, Mega ST, Stacy and the STE series; 3½ ″ SCSI hard disk (20–80 MB, only with some Stacys and Mega STE), almost any selection of SCSI drives with SCSI-I / II interface up to 1 GB capacity via SCSI host adapter.


The following are standard features of all ST variants:

  • Monitor : 13-pin DIN socket for connecting the Atari monitors from the SM / SC series, in color mode an NTSC or PAL compatible RGB video signal is delivered
  • Mouse / joystick : 9-pin D-SUB connector for connecting mice, joysticks, graphics tablets, etc.
  • Floppy : 14-pin DIN socket for connecting up to 2 floppy disk drives (only one external drive is possible with a built-in drive)
  • Hard Disk : Also known as ACSI or DMA, 19-pin D-SUB connector for external hard / removable disks, CD-ROM drives (CDAR504) and laser printers (SLM series). ACSI is closely related to SCSI .
  • Parallel : 25-pin D-SUB socket for connecting printers, for example
  • Serial : Serial interface of the ST, 25-pin D-SUB connector, for connecting modems or for setting up serial networks
  • MIDI In / Out : One five-pin DIN socket each for connecting synthesizers, etc., can also be used for peer-to-peer networks (Midinet)
  • ROM port: 40-pin circuit board connector, to accommodate program modules or external hardware (e.g. scanners or copy protection dongles)

Some model variants also have additional connections:

  • HF modulator : Cinch socket for connecting the ST computer to the antenna input of a television (STM, STFM, STE and later 520 ST)
  • Audio R / L : 1 cinch socket each for connection to an amplifier or stereo system (STE only)
  • Controller 3 + 4 : 15-pin D-SUB socket (same as the VGA interface), game controllers (for example the Atari Jaguar's pad ) can be connected there (STE only)
  • Keyboard : 6-pin Western socket for connecting the Atari keyboards (only Mega ST and Mega STE)

Model variants


  • 130ST (prototype): ST with only 128 KiB RAM, which is not enough for TOS alone (complete TOS 1.0: 192 KiB)
  • 260ST (1985–1986): first ST launched on the market with external 3½ ″ floppy disk drive, 512 KiB RAM, TOS on floppy disk
  • 520ST (1985–1986): essentially identical to the 260ST, TOS was permanently installed here (socketed EPROMs ).
  • 520STM (1985–1989): 520ST with HF modulator for operation on the antenna socket of the television. Has been renamed to 520ST.
  • 520ST + (1985-1987): 1 MiB RAM
  • 520STF (1986–1987): internal double-sided 3½ "floppy disk drive
  • 520STFM (1986–1987): internal 3½ ″ single-sided floppy disk drive and RF modulator
  • 1040STF (1986–1989): 1 MiB RAM, internal double-sided 3½ "floppy disk drive
  • 1040STFM (1986–1992): 1 MiB RAM, internal double-sided 3½ ″ floppy disk drive and HF modulator
  • 2080ST (1986): less common model with 2 MiB RAM and internal double-sided 3½ ″ floppy disk drive
  • 4160ST (prototype): 4 MiB RAM. The memory increased dramatically, so the model was abandoned
  • Mega ST 1, 2 and 4, Mega 1, 2 and 4 (1987–1991): Models with a separate keyboard and, depending on the number, 1, 2 or 4 MiB RAM. Has its own slot called Mega-ST-Bus for an expansion card and the blitter. In later models, the model designation "Mega ST" was shortened to "Mega".
  • 1040STE (1989–1994): see separate article
  • 520STE (1989–1991): 1040STE with 512 KiB RAM, otherwise identical
  • 1040STE + (prototype): 1040STE with built-in hard disk and AT emulator based on 80386 .
  • TT030 (1990–1994): see own article
  • Mega STE (1991–1994): see own article
  • EST (prototype): ST with 68020
  • FX-1 "Sparrow" (prototype): Pre-stage of the Falcon 030
  • Falcon 030 (1992–1994): see separate article
  • Falcon 040 (prototype): extended desktop version of the Falcon 030
  • Falcon "Microbox" (prototype): Falcon on a small desktop housing, housing design was later Sony for PlayStation 2 developed


Atari Stacy2
  • Stacy, Stacy2, Stacy4 (1989–1992): portable, 7.5 kg heavy variant of the Mega ST, optionally with built-in hard disk, but without blitter. With 12 ″ LCD . Battery operation was originally intended, but with a running time of only 15 minutes, the decision was made to leave the battery compartment empty.
  • ST-Book (1991–1992): Notebook in which great value was placed on saving energy. Except for the 2½ ″ hard drive, there are no drives, nor are there any lights on the 12 ″ LCD. Battery life between 5 and 10 hours, depending on operation.
  • ST-Pad “Stylus” (prototype): Atari ST with pen input with handwriting recognition as a forerunner of modern tablet computers. Only two flash modules that can be used in parallel were used as mass storage devices.


  • Atari Transputer Workstation 800 (1988): So-called transputer based on the T800 chips. A modified MegaST integrated into the ATW housing was used as the control terminal for the multiprocessor system.

Atari periphery

Interfaces of the Atari 520ST

Data storage

  • SF314: external double-sided 3½ ″ floppy disk drive, written by the original TOS with 726,016 bytes, format based on FAT12 largely MS-DOS-compatible, which uses 4 KB more.
  • SF354: external single-sided 3½ ″ floppy disk drive, written by the original TOS with 357,379 bytes, format analogous to SF314
  • SH204: 20 MB MFM hard drive with Adaptec ACB 4000 controller, ACSI interface, housing in shoebox format
  • SH205 (later Megafile 20 ): 20 MB MFM hard disk with Adaptec ACB 4000 controller, ACSI interface, housing in the form of an Atari Mega ST
  • Megafile 30: 30 MB RLL hard drive with Adaptec ACB 4000 controller, ACSI interface, housing in the form of an Atari Mega ST
  • Megafile 60: 60 MB RLL hard drive with Adaptec ACB 4000 controller, ACSI interface, housing in the form of an Atari Mega ST
  • Megafile 44: 44 MB removable hard disk with SQ555 drive from SyQuest , ACSI-to- SCSI host adapter, housing in the form of an Atari Mega ST
  • CDAR504: CD-ROM drive, ACSI interface, can also be used as an independent CD player , detachable IR remote control


  • SLM804: 300 dpi laser printer. Similar to today's GDI printers, the page to be printed was calculated in the main memory of the Atari ST / TT and only then sent to the printer.
  • SLM605: 300 dpi laser printer. Successor to the SLM804 with a different printing unit.
  • SMM804: dot matrix printer

Remote data transmission

  • SX212: Modem, transfer rate 1200  baud , serial and Atari SIO interfaces


model size resolution image refresh
SM124 12 ″ 640 × 400 70 Hz
SM125 12 ″ 640 × 400 70 Hz
SM144 14 ″ 640 × 400 70 Hz was launched on the market together with the Atari Mega STE.
SM146 14 ″ 640 × 400 70 Hz
SM147 14 ″ 640 × 400 70 Hz distributed in the US only
SM194 19 ″ 1280 × 960 70 Hz could be operated with a special graphics card on the system bus of the Mega-ST series.
SM195 19 ″ 1280 × 960 70 Hz ECL signal, could be controlled directly by the Atari TT
PS3000 12 ″ 320 × 200 and 640 × 200 with internal single-sided 3½ ″ floppy disk drive (very rare, only sold in North America)
SC1224 12 ″ 320 × 200 and 640 × 200 according to PAL standard, with RGB signal input and Atari-specific connector
SC1425 14 ″ 320 × 200 and 640 × 200 with SCART input (see Commodore 1084)
SC1435 14 ″ 320 × 200 and 640 × 200 with stereo speaker (see Philips CM-8833-II)

Peripherals / extensions from other manufacturers (selection)

  • Autoswitch overscan: The small board required some soldering on the ST series. The purpose of the extension was to increase the image resolution. B. 768 × 520 pixels achievable. For this, however, the SM124 monitors had to be partially readjusted.
  • ACSI-to-SCSI host adapter: e.g. B. from ICD, ICP-Vortex, and others. This made it possible to connect cheaper SCSI peripherals such as hard disks, CD-ROM drives, streamers, etc. to the Atari ST series. Manufacturers named also supplied competitor products based on host adapters in competition with Atari's Megafile series. Particularly popular was z. B. the Vortex HD-20 in competition with the SH204 or Megafile 20.
  • Hardware PC emulator Beta-Systems Supercharger: A small white box with an NEC V20 with 1 MiB RAM, 8 MHz clock speed and a special chipset inside . On the one hand, the chipset provided a PC-compatible hardware environment and, on the other hand, handled communication with the Atari ST / TT via the ACSI interface. The Supercharger thus represented a PC / XT-compatible PC whose keyboard / mouse and graphics card (CGA and Hercules compatible) were the Atari computers. The mass storage connection was also made via the Atari. TOS / GEM programs could also be executed on the Atari in parallel and you could switch between the two systems with a special key combination.
  • Hardware PC emulator vortex ATOnce: An installation kit to be plugged into the processor socket, which uses the main memory of the ST, with 8 MHz, later 16 MHz clock speed. On the one hand, the chipset provided an IBM PC-compatible hardware environment and, on the other hand, handled communication with the Atari ST. The ATOnce was a PC / AT-compatible PC corresponding to an 80386SX, which already had more main memory available below the 640 KiB limit than an "original" IBM-compatible PC. Partitions up to 16 MiB could be read and written by both systems.
  • PAK68, PAK68 / 2, PAK68 / 3: P rozessor- A ustausch- K arte. These extensions served to accelerate the ST systems by replacing the Motorola 68000 processor with its non-pin-compatible successors 68020 and 68030. The PAK was placed on the motherboard instead of the original processor and made the mechanical and electronic adaptation to the new processor. With the help of the PAK, the system speed of the ST computers could be increased considerably; Depending on the clock frequency, the upgraded systems reached the speed of the successors TT and Falcon or even exceeded them. The PAK was a project of the c't magazine published by Heise-Verlag .

Further use of Atari ST data on current computers

A wealth of emulators for Atari ST are circulating on the Internet . Most of these emulators, however, require an image of original Atari ROMs for their function, so for licensing reasons they may only be used if the owner of the computer is also the owner of an Atari ST (or his ROMs). The legal solution is to use post-programmed, freely available TOS versions such as EmuTOS.

Atari floppy disks can usually be read by a PC (or an older Apple Macintosh ). However, difficulties arise with umlauts in path and file names due to the different character sets as well as higher formatted floppy disks (i.e. with more than 80 tracks and / or more than 9 sectors per track); these only work reliably with an original Atari computer and must therefore be copied over. If no corresponding Atari computer is available, this can be done e.g. As with the live CD of ARAnyM done. This way, which is unproblematic in terms of licensing and does not require any installation on the “host PC”, makes it possible to read older Atari diskette formats on PC hardware and to copy the files to DOS-formatted diskettes. Another possibility: 2DD disks, which are formatted under MS-DOS with the command format a: / u / f: 720 , can be read and written by the Atari as well as by Windows and therefore serve as a transport medium between the two computer worlds. Windows XP supports the parameter 720: / f no more, so you have to on format / t: 80 / n: 9a: dodge.

Since current PCs do not have a floppy disk drive, there are still solutions to either burn the data to CD, retrofit a floppy disk drive or connect a USB drive, removable media such as ZIP , JAZ or DVD-RAM drives, memory cards such as CF and SD (the Atari can read and write PC-compatible hard and removable disks and memory cards with suitable software such as the HDDRiver or BIGDOS) or to connect the Atari and the current computer to the Atari using a network card (EtherNEC or EtherNEA) and usually an existing network connection.

Hatari is an open source emulator .

A professional Atari emulator for Apple Macintosh is MagiC Mac (X). This emulator provides Calamus u. a. a printer interface is available so that Calamus can recognize and address any printer installed on the Apple side. However, this printer driver no longer works on the Intel MagicMac version. Calamus SL users make do with the PDF export and then print out the generated PDF files under OS X.

The counterpart MagiC PC is available for Windows operating systems . The STemulator runs on Windows 7-32 bit.

For the Apple computers Performa 450 , 475 and 630 there was also (1995) a MagicMac-compatible interface card with Mac STout , which retrofitted the parallel (Centronics / printer) interface and a serial interface with original Atari chips that did not exist on the Macintosh . In connection with MagiC Mac, programs such as Wordplus, Signum! , Script or Calamus print with PC printers, and Atari programs ran on the Macintosh at about four times the speed of an Atari TT . McSTout also existed in a variant that also provided MIDI ports.


  • The Berlin digital hardcore band Atari Teenage Riot consciously produces their music on an ST to this day.
  • Some programmers develop sound generators for the Atari based on the model of PGP and other synthesizers

Well-known software for Atari ST

See also Category: Atari ST Game .


  • Jankowski, Reschke, Rabich: Atari ST / TT-Profibuch , Sybex-Verlag, ISBN 3-88745-501-0 .
  • Claus Brod, Anton Stepper: Disk paste II - mass storage at Atari ST , Maxon Verlag, ISBN 3-927065-00-5 .
  • B. Grohmann, P. Seidler, H. Silbar: The machine language book for the Atari ST , Data Becker book, ISBN 3-89011-120-3 .
  • Gerits, English, Brückmann: Atari ST Intern , Data Becker Book, ISBN 3-89011-119-X .
  • O. Hartwig: Atari ST for Insider , Markt & Technik Verlag, ISBN 3-89090-423-8 .
  • J. Muus, W. Besenthal: Programming Practice Omikron Basic 3.0 , Markt & Technik Verlag, ISBN 3-89090-608-7 .
  • A. Aumiller, D. Luda, G. Möllmann: Atari ST GEM programming in C , Markt & Technik Verlag, ISBN 3-89090-488-2 .
  • P. Wollschläger: Atari ST assembler book , Markt & Technik Verlag, ISBN 3-89090-467-X .

Web links

Commons : Atari ST  - collection of pictures, videos and audio files

Individual evidence

  1. LEAD-R for Atari. Retrieved July 24, 2020 .
  2. ATAreSYN for Atari. Retrieved July 24, 2020 .