|Release date||June 1985|
US$ 799.99 (monochrome)US$ 999.99 (with color monitor)
|Operating system||Digital Research's GEM run via Atari TOS|
|CPU||Motorola 680x0 @ 8 MHz & higher|
|Memory||512 kilobytes (512×210 bytes) to 4 megabytes (4×220 bytes)|
The Atari ST is a home computer released by Atari Corporation in June 1985. Development machines were distributed around May 1985 and it was available commercially 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. Due to its graphical user inferface, it was jokingly referred to as the "Jackintosh", a reference to Jack Tramiel.
The Atari ST was part of the 16/32 bit generation of home computers, based on the Motorola 68000 CPU, typically with 512 kB of RAM or more, a graphical user interface, and 3½" microfloppy disks as storage. It was similar to the Apple Macintosh, and its simple design allowed the ST to precede the Commodore Amiga's commercial release by almost two months. The Atari ST was also the first personal computer to come with a bit-mapped color GUI, using a version of Digital Research's GEM released that February.
The ST was primarily a competitor to the Apple Macintosh, Commodore Amiga and in certain markets the Acorn Archimedes. Where the Amiga had a graphics accelerator and wavetable synthesis, the ST had a simple frame buffer and a 3 voice synthesizer chip but with a CPU faster clocked, and had a high-resolution monochrome display mode, ideal for business and CAD. In some markets, particularly Germany, the machine gained a strong foothold as a small business machine for CAD and Desktop publishing work. The Atari ST also enjoyed some market popularity in Canada.
The ST was also the first home computer with integrated MIDI support. Thanks to its built-in MIDI, it enjoyed success for running music-sequencer software and as a controller of musical instruments among amateurs and professionals alike, being used in concert by bands and performers such as Jean Michel Jarre, Madonna, Eurythmics, Tangerine Dream, Fatboy Slim, and 1990s UK dance acts Utah Saints & 808 State, as well as naming German digital hardcore band Atari Teenage Riot.
Amiga contract 
The Atari ST was born from the rivalry between home-computer makers Atari, Inc. and Commodore International. Jay Miner, one of the original designers for the custom chips found in the Atari 2600 and Atari 8-bit family, tried to convince Atari management to create a new chipset for a video game console and computer. When his idea was rejected, Miner left Atari to form a small think tank called Hi-Toro in 1982 and began designing the new "Lorraine" chipset. The company, which was later renamed Amiga Corporation, was pretending to sell video game controllers to deceive competition while it developed a Lorraine-based computer.
Amiga ran out of capital to complete Lorraine's development, and Atari, owned by Warner Communications, paid Amiga to continue development work. In return Atari received exclusive use of the Lorraine design for one year as a video game console. After one year Atari would have the right to add a keyboard and market the complete computer, designated the 1850XLD. As Atari was heavily involved with Disney at the time, it was later code-named "Mickey", and the 256K memory expansion board was codenamed "Minnie".
Tramel Technology 
After leaving Commodore International in January 1984 Jack Tramiel formed Tramel Technology with his sons and other ex-Commodore employees, and in April began planning a new computer. The company initially considered the National Semiconductor NS320xx microprocessor, but was disappointed with its performance. This started the move to the 68000.
Tramiel learned that Warner wanted to sell Atari, which in mid-1984 was losing about a million dollars per day. Interested in Atari's overseas manufacturing and world wide distribution network for his new computer, Tramiel negotiated with Warner in May and June 1984. He secured funding and bought Atari's Consumer Division (which included the console and home computer departments) in July. As executives and engineers left Commodore to join Tramiel's new Atari Corporation, Commodore responded by filing lawsuits against four former engineers for theft of trade secrets. This was intended to, in effect, bar Tramiel from releasing his new computer.
One of Tramiel's first acts after forming Atari Corp. was to fire most of Atari's remaining staff and cancel almost all ongoing projects in order to review their continued viability. It was during this time in late July/early August that his representatives discovered the original Amiga contract, which required Amiga Corporation to deliver the Lorraine chipset to Atari on June 30, 1984. Amiga Corp. had sought more monetary support from investors in spring 1984 (among them Tramel Technology, which wished to replace nearly everyone at Amiga).
Commodore and Amiga 
Having heard rumors that Tramiel was negotiating to buy Atari, Amiga Corp. entered into discussions with Commodore. The discussions led to Commodore wanting to purchase Amiga Corporation outright, which Commodore believed would cancel any outstanding contracts, including Atari's. Instead of Amiga Corp. delivering Lorraine to Atari, Commodore delivered a check of $500,000 to Atari on Amiga's behalf, in effect returning the funds Atari invested into Amiga for the chipset. Tramiel countersued Amiga Corp. on August 13, 1984. He sought damages and an injunction to bar Amiga (and effectively Commodore) from producing anything with its technology.
At Commodore, the Amiga team was in limbo during the summer of 1984 because of the lawsuit. No word on the status of the chipset, the Lorraine computer, or the team's fate was known. In the fall of 1984, Commodore informed the team that the Lorraine project was active again, the chipset was to be improved, the operating system developed, and the hardware design completed. While Commodore announced the Amiga 1000 with the Lorraine chipset in July 1985, the delay gave Atari, with its many former Commodore engineers, time to deliver the first Atari ST units in June 1985. In March 1987, the two companies settled the dispute out of court in a closed decision.
Operating system 
With the hardware design nearing completion, the Atari team started looking at solutions for the operating system. Soon after the Atari buyout, Microsoft approached Tramiel with the suggestion that they port Windows to the platform, but the delivery date was out by about two years, far too long for their needs. Another possibility was Digital Research, who were working on a new GUI-based system then known as Crystal, soon to become GEM. Another option was to write a new operating system in-house, but this was rejected as Atari management was unsure whether the company had the required expertise to do so.
Digital Research was fully committed to the Intel platform, so a team from Atari was sent to the Digital Research headquarters to work with the "Monterey Team" which comprised a mixture of Atari and Digital Research engineers. Atari's Leonard Tramiel was the Atari person overseeing "Project Jason" (aka — The Operating System) for the Atari ST line of computers. The name came from the original designer and developer, Jason Loveman. Tim Oren has an article describing the history of the project, from his series "Professional GEM."
CP/M-68K was essentially a direct port of CP/M's original, mature operating system. By 1985, it was becoming increasingly outdated in comparison to MS-DOS 2.0; for instance, CP/M did not support sub-directories. Digital Research was also in the process of building a new DOS-like operating system specifically for GEM, GEMDOS, and there was some discussion of whether or not a port of GEMDOS could be completed in time for product delivery in June. The decision was eventually taken to port it, resulting in a GEMDOS file system which became part of TOS (The Operating System) and colloquially known as the (Tramiel Operating System). This was beneficial as it gave the ST a fast, hierarchical file system, essential for hard drive storage disks, plus programmers had function calls similar to the IBM PC DOS.
After six months of intensive effort following Tramiel's takeover, Atari announced the 520ST at the Winter Consumer Electronics Show in Las Vegas in January 1985. Due to its similarities to the original Apple Macintosh and Jack Tramiel's role in its development, it was quickly nicknamed the "Jackintosh". Many observers were amazed by Atari's rapid development of the ST  but others were more skeptical, citing the ST's "cheap" appearance, the poor relations Commodore under Tramiel had had with software developers, and Atari's uncertain financial health. The majority of software companies were hesitant to support another platform beyond the IBM PC, Apple, and Commodore 64, and some were unsure of whether to choose the ST or the Amiga.
Although Atari was out of cash and its employees feared that Tramiel would shut the company down, the 520ST shipped during spring 1985 to the press and developers and then in early July 1985 for general retail sales, saving the company. The machine had gone from concept to store shelves in a little under a year. Atari had originally intended to release versions with 128 kB and 256 kB of RAM as the 130ST and 260ST respectively. However, with the OS loaded from floppy into RAM, there would be little or no room left over for applications to run. The 260ST did make its way into Europe on a limited basis.
The ST could support a monochrome or color monitor. The former was less expensive, and had a higher resolution with its 640 × 400. Due to its flicker-free operation at 72 Hz, the monochrome monitor was better suited to business applications. The hardware supported two different color resolutions, 320 × 200 with 16 out of 512 colors, or 640 × 200 with 4 out of 512 colors. Color was required by a majority of games.
Early models shipped with TOS on disk, but were designed with ROM sockets to make for easy upgrading to the future ROM-based TOS. These became available only a few months later, and were included in all new machines, as well as being available to upgrade older machines. By late 1985 the machines were also upgraded with the addition of an RF modulator (for TV display), a version known as the 520STM.
Atari had originally intended to include GEM's GDOS (Graphical Device Operating System), which allowed programs to send GEM VDI (Virtual Device Interface) commands to drivers loaded by GDOS. This allowed developers to send VDI instructions to other devices simply by pointing to it. However, GDOS was not ready at the time the ST started shipping, and was included in software packages and later ST machines. Later versions of GDOS supported vector fonts.
A limited set of GEM fonts were also included within the ROMs. These fonts also featured two additions:
- The standard 8x8 pixel graphical character set for the ST (the main in-ROM "font" for GEM, and text-mode TOS operations in color modes) contains, following all the standard numbers, letters, symbols and accented characters, four unusual characters. These can be placed together in a square, forming a basic but recognisable facsimile of the face of J. R. "Bob" Dobbs, the figurehead of the Church of the Subgenius.
- Jack Tramiel chose to include the Hebrew alphabet with ST's ROM character set because of his Jewish heritage.
On the plus side, the ST was less expensive than most machines, including the Macintosh Plus, and tended to be faster than most (external link: price comparison). Largely as a result of the price/performance factor, the ST would go on to be a fairly popular machine, notably in European markets where the foreign-exchange rates amplified prices. Indeed, the company's English advertising strapline of the era was "power without the price." In fact, an Atari ST and terminal emulation software was much cheaper than a Digital VT220 terminal, which was commonly needed by offices with central computers.
Original housing 
The original 520ST case design was created by Ira Velinsky — Atari's chief Industrial Designer. The ST was basically wedge shaped, featuring bold angular lines and a series of grilles cut into the rear for airflow. The keyboard had soft tactile feedback and rhomboid-shaped function keys across the top. The 520ST was an all-in-one unit, similar to earlier home computers like the Commodore 64. By the time the 520ST reached the market, however, consumers demanded a keyboard with cursor keys and a numeric keypad. For this reason, the 520ST ended up significantly larger than previous popular all-in-one machines like the Commodore 64.
The 520ST used an external "brick" power supply, floppy disk, monitor and mouse. Even basic system setups thus suffered from cable spaghetti, a problem future versions would address to one degree or another. Early 520ST owners became accustomed to the "Atari Twist" and the "Atari Drop" service procedures. The "Atari Twist" seemed to help discharge built-up static electricity (Atari soldered-down the metal shielding to fix the problem) while the "Atari Drop" appeared to help re-seat chips which may have become partially unseated over time.
Port connections 
The 520ST featured a large number of ports mounted at the rear of the machine. The basic port layout would remain largely unchanged over the machine's history.
- Standard ports:
- ST-specific ports:
Because of its bi-directional design, the Centronics printer port could be used for joystick input, and several games made use of available adaptors that plugged into the printer socket, providing two additional 9-pin joystick ports.
Atari initially used single-sided disk drives that could store up to 360 kB. Later drives were double-sided versions that stored 720 kB. Due to the early sales of so many of the single-sided drives, almost all software would ship on two single-sided disks instead of a single double-sided one, for fear of alienating early adopters. ST magazines wishing to cater to the entire audience while still supplying a large amount of material on a single cover disc had to adopt innovative custom formats to work around this problem. Another sticking point was that, while the Atari double-sided drive could read IBM-formatted disks, IBM PCs could not read Atari disks. This was a formatting issue that was later resolved by third-party software formatters and TOS upgrades (1.44 and higher).
STF and STFM models 
Atari later upgraded the basic design in 1986 with the 1040STF (also written STF). The machine was generally similar to the earlier 520ST, but moved the power supply and a double-sided floppy drive into the rear of the housing of the computer, as opposed to being external. This added to the size of the machine, but reduced cable clutter in the back. However, the joystick/mouse ports, formerly on the right side of the machine where the disk now sat, had to be moved to an awkward location in a cramped niche underneath the keyboard.
The 1040ST was the first personal computer shipped with a base RAM configuration of 1 MB. When the list price was reduced to $999 in the U.S. it appeared on the cover of BYTE in March 1986 as the first computer to break the $1000/megabyte price barrier. However, the ST remained generally the same internally over the majority of its several-year lifespan. The choice of model numbers was inherited from the model numbers of the XE series of the Atari 8-bit family of computers. A limited number of 1040STFs shipped with a single-sided floppy drive.
The same basic design was also used for a cut-down version, the 512 kB 520STFM, which replaced the earlier 520ST models in the market. The early 'STF' machines lacked the 'M' modulator that allowed a TV to be used and would only work with a monitor.
Mega models 
Initial sales were strong, especially in Europe where Atari sold 75% of its computers. Germany became Atari's strongest market, with small business users using them for desktop publishing and CAD.
To address this growing market segment, Atari came up with the ST1. First debuted at Comdex, 1986, it was received favorably. Renamed the Mega, this new machine included a high-quality detached keyboard, a stronger case to support the weight of a monitor, and an internal bus expansion connector. The upcoming SLM804 laser printer would not come with a processor or memory, reducing costs. It would attach to the Mega through the ST DMA port and have the Mega computer render the pages. Initially equipped with 2 or 4 MB (a 1 MB version, the Mega 1 would later follow), the Mega machines would complement the Atari laser printer for a low-cost desktop publishing package, which received acclaim and was featured on the cover of Computer Shopper magazine.
A custom blitter co-processor was to be included to speed the performance of some graphics operations on the screen, but due to delays it was eventually released on the Mega 2 and Mega 4 machines. Developers wanting to use it had to detect for it in their programs because it was not present on all machines. However, properly written programs using the screen VDI commands could use the blitter seamlessly, since GEM API was a higher-level interface to TOS.
Later models 
For about the first four years, no major design changes in the ST platform took place, as Atari focused on manufacturing problems and distribution.
STE models 
In late 1989, Atari released the 520STE and 1040STE (also written STE), enhanced version of the ST with improvements to the multimedia hardware and operating system. It featured an increased color palette of 4096 colors from the ST's 512 (though the maximum displayable palette of these without programming tricks was still limited to 16 in the lowest 320x200 resolution, and even fewer in higher resolutions), Genlock support, and a graphics co-processor chip called Blitter, which could quickly move large blocks of data (most particularly, graphics sprites) around in RAM. It also included a new 2-channels digital sound chip that could play 8-bit stereo samples in hardware at up to 50 kHz. Two enhanced joystick ports (EJP) were added (two normal joysticks could be plugged into each port with an adaptor), with the new connectors placed in more easily accessed locations on the side of the case. The enhanced joystick ports were re-used in Atari's Jaguar console, and are compatible. RAM was now much more simply upgradable via SIMMs. Despite all of this, it still ran at 8 MHz.
The STE models initially had software and hardware conflicts resulting in some applications and video games written for the ST line being unstable or even completely unusable, primarily caused by programming direct hardware calls which bypassed the operating system. Sometimes incompatibility could be solved by expanding the RAM. Furthermore, even having a joystick plugged in would sometimes cause strange behaviour with a few applications (such as the WYSIWYG word-processor application First Word Plus).
The STE was the first Atari with PCM audio, which was probably one of the most attractive features of the machine. It has the ability to play back 8-bit (signed) samples using the SDMA at the following frequencies: 6258 Hz, 12517 Hz, 25033 Hz and 50066 Hz—sampling frequencies above audio CDs, although, the resolution was still only 8 bit. The channels are arranged as either a mono track or a track of LRLRLRLR... bytes.
Very little use was made of the extra features of the STE: STE-enhanced and STE-only software were rare, generally being limited to serious art-, CAD-, or music applications, with very few games taking advantage of the hardware, since it was found on so few machines.
The last STE machine, the Mega STE, was an STE in a grey Atari TT case that had a switchable 16 MHz, dual-bus design (16-bit external, 32-bit internal), optional Motorola 68881 FPU, built-in 3½" floppy disk drive, VME expansion slot, a network port (very similar to that used by Apple's LocalTalk) and an optional built-in 3½" hard drive. It also shipped with TOS 2.00 (better support for hard drives, enhanced desktop interface, memory test, 1.44 MB floppy support, bug fixes). It was marketed as more affordable than a TT but more powerful than an ordinary ST.
Atari TT 
In 1990, Atari released the high-end workstation-oriented Atari TT030, based on a 32 MHz Motorola 68030 processor. The "TT" name ("Thirty-two/Thirty-two") continued the nomenclature system as the 68030 chip had full 32-bit wide buses both internally and externally. Originally planned with a 68020 CPU, the TT included improved graphics and more powerful support chips. The case was a new design with an integrated hard-drive enclosure.
Atari Falcon 
The final ST computer was the multimedia-capable Atari Falcon030. Like the TT, this was also 68030-based, operating at 16 MHz, but with improved video modes and an on-board Motorola 56001 audio digital signal processor. The Falcon, like the Atari STE, supports sampling frequencies above 44.1 kHz; the sampling master clock is 98340 Hz, which can be divided by a number between 2 and 16 to get the actual sampling frequencies. Apart from these frequencies, it is also able to play the STE sample frequencies (up to 50066 Hz) in 8 or 16 bit, mono/stereo, all by using the same DMA interface as the STE, with a few additions. The Falcon can both play back and record samples; it has 8 mono channels / 4 stereo channels; thus this allowed musicians to use the computer for harddisk recording. Although the 68030 microprocessor was capable of using 32-bit memory, the Falcon used a 16-bit bus which affected performance, but also served to reduce its cost. In another cost-reduction measure, Atari shipped the Falcon in an inexpensive case much like that of the STE. Aftermarket upgrade kits were available that allowed the Falcon to be put in a desktop or rack-mount case, with the keyboard separate.
Released in 1992, the Falcon was canceled by Atari the following year. In Europe, C-Lab licenced the Falcon design from Atari, and released the C-Lab Falcon Mk I (the same as Atari's Falcon except for some slight modifications to the audio circuitry), Mk II (as Mk I but with an internal 500 MB SCSI hard disk) and Mk X (as Mk II but in a desktop case).
In 1993, Atari cancelled development on the ST computers to focus on the Jaguar.
Following the exit of Atari from the computer market, Medusa Computer Systems manufactured some powerful 3rd-party Atari Falcon/TT-compatible machines that used 68040 and 68060 processors, based on multimedia (particularly audio, but also video), CAD, and office uses.
Despite the lack of a hardware supplier, there is a small active community dedicated to keeping the ST platform alive. There have been advancements in the operating system, software emulators (for Windows, Mac & Linux), and some hardware developments. There are accelerator cards, such as the CT60 & CT63, which is a 68060 based accelerator card for the Falcon, and there is the Atari Coldfire Project, which aims at developing an Atari-clone based on the Coldfire processor. Milan Computer of Germany also made 68040 and 68060-based Atari clones that can run either Atari TOS 4.5 or Milan Computer's MultiOS operating system.
Music and sound 
The ST was the first home computer with built-in MIDI ports, and there was plenty of MIDI-related software for use professionally in music studios, or by amateur enthusiasts. The popular Windows/Macintosh applications Cubase and Logic Pro originated on the Atari ST (the latter as Notator Logic, preceded by Creator, Notator and Notator-SL). Another popular and powerful ST music sequencer application, Dr. T's KCS, contained a "Multi-Program Environment" that allowed ST users to run other applications, such as the synthesizer patch editing software XoR (now known as Unisyn on the Macintosh), from within the sequencer application.
Music tracker software was popular on the ST, such as the TCB Tracker, aiding the production of quality music from the Yamaha synthesizer ('chiptunes').
An innovative music composition program that combined the sample playing abilities of a tracker with conventional music notation (which was usually only found in MIDI software) was called Quartet (after its 4-note polyphonic tracker, which displayed one monophonic stave at a time on colour screens).
Due to the ST having comparatively large amounts of memory for the time, sound sampling packages became a realistic proposition. The Microdeal Replay Professional product featured a sound sampler that cleverly used the ST cartridge port to read in parallel from the cartridge port from the ADC. For output of digital sound, it used the on-board frequency output, set it to 128 kHz (inaudible) and then modulated the amplitude of that.
Another program that had good success on the ST platform was MasterTracks Pro from Passport Designs, of Half Moon Bay, CA., that was first put out by Don Williams for the Macintosh. When the ST died, a PC version continued that one could port MIDI to using the generic .MID format. GVox bought out Passport, and continues the program for Windows and Mac OS along with the other Passport product, the notation program Encore.
In addition to the sound-sampling functionalities, the availability of software packages with MIDI support for music composition and efficient sound analysis contributed to make the Atari ST a forerunner of later computer-based all-in-one studios.
The ST's low cost, built-in MIDI ports, and fast, low-latency response times made it a favorite with musicians:
- Atari Teenage Riot named itself after the brand and programmed most of their music on an Atari ST. Including the entire album Is This Hyperreal? (June, 2011).
- The Fatboy Slim album You've Come A Long Way, Baby has an Atari ST in the large foldout picture of Fatboy Slim's studio.
- Highly acclaimed electronic music artists Mike Paradinas and Luke Vibert started out writing music on Atari STs.
- Mike Oldfield's album Earth Movings album notes state that it was recorded using an Atari ST and C-Lab MIDI software.
- In the Paris performance of Jean Michel Jarre's album Waiting for Cousteau, musicians have attached Atari ST machines with unidentified MIDI software to their keyboards, as could be seen in the TV live show and video recordings.
- White Town's "Your Woman", which reached #1 in the UK singles charts, was created using an Atari ST.
- The Utah Saints used STs during the recording of both of their albums, Utah Saints & Two
Also popular on the ST was professional desktop publishing software, such as PageStream and Calamus; office tools such as word processors (WordPerfect, Microsoft Write, AtariWorks, WordWriter ST, First Word [shipped with the machine] and its Plus continuation, and others); spreadsheets (3D-Calc, LDW Power, LDW Power 2, LOGiSTiX Senior, PowerLedger ST, SwiftCalc ST, VIP Professional, and others); turnkey programs (Mail-Pro, Sales-Pro 6, Video-Pro, and others); database programs (A-Calc Prime, Data Manager, Data Manager Professional, DBMan V, Base Two, Informer II, DB Master One, SBT Database Accounting Library (dLedger, dInvoice, dOrder, dPurchases, and dPayables), Superbase Personal, Superbase Professional, Tracker ST, and others); and various CAD and CAM tools from amateur hobbyist to professional grade (Campus CAD, DynaCADD, Leonard ST, Technobox CAD/2...): all being largely targeted at, or even limited to owners of high-resolution monochrome monitors.
Graphics programs such as NEOchrome, Degas & Degas Elite, Canvas, Deluxe Paint, and Cyber Paint (which author Jim Kent would later evolve into Autodesk Animator) featured advanced features such as 3D design and animation. One paint program, Spectrum 512, used the ST's rapid palette switching ability to expand the maximum number of colors to be displayed on-screen at once to 512 (up to 46 in each scan line — the STE never had a Spectrum4096, but other more minor applications filled this speciality niche, one even going so far as to program the shifter chip to palette shift at a rate enabling a display of 19200 colours).
3D computer graphics applications (like Cyber Studios CAD-3D, which author Tom Hudson would later develop into Autodesk 3D Studio), brought 3D modelling, sculpting, scripting, and most important, computer animation (using delta-compression) to the desktop. Video-capture and -editing applications using special video-capture 'dongles' connected using the cartridge port — low frame rate, mainly silent and monochrome, but progressing to sound and basic colour (in still frames) by the end of the machine's life. At the end, Spectrum 512 and CAD-3D teamed up to produce realistic 512-color textured 3D renderings, but processing was slow, and Atari's failure to deliver a machine with a math coprocessor had Hudson and Yost looking towards the PC as the future before a finished product could be delivered to the consumer.
The Atari ST was the computer upon which today's prevalent graphical touchscreen point of sale software for restaurants was originally developed. This software was created by Gene Mosher under the ViewTouch copyright and trademark. It did not feature the Atari ST's GEM graphical user interface but, instead, featured an application specific graphical user interface and widget framework which he developed using, in part, the Neochrome paint program.
Software development 
The Atari ST had a wide variety of languages and tools for development. 68000 assemblers (MadMac from Atari Corp, HiSoft Systems's Devpac, TurboAss, GFA-Assembler), Pascal (OSS Personal Pascal, Maxon Pascal, PurePascal), Modula-2, C compilers (like Turbo C (Borland), Alcyon C, Lattice C, Megamax C, Mark Williams C, GNU C, Aztec C, AHCC (A Home Cooked C)), LISP, Prolog, Logo, and many others.
The initial development kit from Atari included a computer and manuals. At $5,000, this discouraged many from developing software for the ST. Later, the Atari Developer's Kit consisted of software and manuals (no hardware) for $300. Included with the kit were a resource kit, C compiler (first Alcyon C, then Mark Williams C), debugger, and 68000 assembler (plus the non-disclosure agreement).
The ST came bundled with a system disk that contained ST BASIC, the first BASIC for the ST. However, due to its poor performance, users favored other BASICs, such as GFA BASIC, FaST BASIC (notable for being one of the few programs to actually be supplied as a ROM cartridge instead of on disc), and the relatively famous STOS, which then inspired and led to the creation of AMOS on the Amiga, and powerful enough that it was used (with a compiler, opposed to its usual runtime interpreter) for the production of at least two commercial titles and an innumerable host of good quality shareware and public domain games. In the late years of the Atari ST Omikron Basic was bundled with it in Germany.
Even novelty tools such as SEUCK were available.
The ST enjoyed success in gaming due to low cost, fast performance and colorful graphics.
Notable individuals who developed games on the ST include Peter Molyneux, Doug Bell, Jeff Minter, Éric Chahi, Jez San, and David Braben. An early real-time 3D role-playing video game, Dungeon Master, was first developed and released on the ST, and was the best-selling software ever produced for the platform. Simulation games like Falcon and Flight Simulator II made use of the enhanced graphics found in the ST machines, as did many arcade ports. One game, MIDI Maze, used the MIDI ports to connect up to 16 machines for interactive networked play, this is sometimes said to have inspired modern LAN games which became popular in the early 90s. Games simultaneously released on the Amiga that had identical graphics and sound were often accused by video game magazines of simply being ST ports. The reason for these accusations is because these games were not utilising the Amiga's ability to produce superior graphics and sound. The critically acclaimed game Another World was originally released for ST and Amiga in 1991 (But developed on Amiga though).
Utility software was available to drive hardware add-ons such as video digitisers. Office Productivity and graphics software was also bundled with the ST (HyperPaint II by Dimitri Koveos, HyperDraw by David Farmborough, 3D-Calc spreadsheet by Frank Schoonjans, and several others commissioned by Bob Katz, later of Electronic Arts).
There was a thriving output of public domain and shareware software which was distributed by, in the days long before public internet access, public domain software libraries that advertised in magazines and on popular dial-up bulletin board systems.
Remarkably, a modest core fanbase for the system, supporting a dwindling number of good quality print magazines, survived to the mid-'90s and the birth of the modern, publicly accessible Internet as we know it. Despite the limited graphics, memory, and temporary hard-storage capabilities of the system, several email, FTP, telnet, IRC, and even full-blown graphical World Wide Web browser applications are available and usable on the ST.
There were also DOS emulators released in the late 80s. PC-Ditto came in two versions, software-only-, and a hardware version that plugged into the cartridge slot or kludged internally. After running the PC-Ditto software, you had to insert a DOS boot disk to load the system. Both allowed you to run DOS programs in CGA mode, though much more slowly than on an IBM PC. Other options were the PC-Speed (NEC V30), AT-Speed (Intel 80286) and ATonce-386SX (Intel 80386sx) hardware emulator boards.
Technical specifications 
All STs were made up of both custom and commercial chips:
- Custom chips:
- ST Shifter "Video shift register chip"—Enabled bitmap graphics using 32 kB of contiguous memory for all resolutions. Screen address had to be a multiple of 256.
- ST GLU "Generalized Logic Unit"—Control logic for the system used to connect the ST's chips. Not part of the data path, but needed to bridge chips with each other.
- ST MMU "Memory Management Unit"— Provides signals needed for CPU/blitter/DMA and Shifter to access dynamic ram. Even memory accesses are given to CPU/Blitter/DMA while odd cycles are reserved for DRAM refresh or used by Shifter for displaying contents of the frame buffer.
- ST DMA "Direct Memory Access"—Used for floppy and hard drive data transfers. Can directly access main memory in the ST.
- Support chips:
- MC6850P ACIA "Asynchronous Common Interface Adapter"—Enabled the ST to directly communicate with MIDI devices and keyboard (2 chips used). 31.250 kbit/s for MIDI, 7812.5 bit/s for keyboard.
- MC68901 MFP "Multi Function Peripheral"—Used for interrupt generation/control, serial and misc. control input signals. Atari TT030 had 2 MFP chips.
- WD-1772-PH "Western Digital Floppy Disk Controller"—Floppy controller chip.
- YM2149F PSG "Programmable Sound Generator"—Provided 3-voice sound synthesis, also used for floppy signalling, serial control output and printer parallel port.
- HD6301V1 "Hitachi keyboard processor"—Used for keyboard scanning and mouse/joystick ports.
As originally released in the 520ST:
- CPU: Motorola 68000 16-/32-Bit CPU @ 8 MHz. 16 bit data/32 bit internal/24-bit address.
- RAM: 512 kB or 1 MB
- Display modes (60 Hz NTSC, 50 Hz PAL, 71.2 Hz monochrome):
- Low resolution: 320 × 200 (16 color), palette of 512 colors
- Medium resolution: 640 × 200 (4 color), palette of 512 colors
- High resolution: 640 × 400 (mono), monochrome
- Sound: Yamaha YM2149 3-voice squarewave plus 1-voice white noise mono Programmable Sound Generator
- Drive: Single-sided 3½" floppy disk drive, 360 kB capacity when formatted to standard 9 sector, 80 track layout.
- Ports: TV out (on ST-M and ST-FM models, NTSC or PAL standard RF modulated), MIDI in/out (with 'out-thru'), RS-232 serial, Centronics parallel (printer), monitor (RGB or Composite Video colour and mono, 13-pin DIN), extra disk drive port (15-pin DIN), DMA port (ACSI port, Atari Computer System Interface) for hard disks and Atari Laser Printer (sharing RAM with computer system), joystick and mouse ports (9-pin MSX standard)
- Operating System: TOS v1.00 ('The Operating System) with the Graphical Environment Manager (GEM) WIMP (Windows, Icons, Menus, Pointer) GUI
Very early machines included the OS on a floppy disk due to it not being ready to be burned to ROM (like the Amiga 1000 had) This early version of TOS was bootstrapped from a very small core boot ROM, but this was quickly replaced with (expanded capacity) ROM versions of TOS 1.0 when it was ready. (This change was also greatly welcomed as older ST machines with memory below 512 kB suffered, as GEM loaded its entire 192 kB code into RAM when booting the desktop). Having the OS loaded from disk was due to Atari trying to rush the machines to market without ironing out all the bugs in the OS. Soon after this change, most production models became STFs, with an integrated single- (520STF/512 kB RAM) or double-sided (1040STF/1024 kB RAM) double density floppy disk drive built-in, but no other changes. The next later models used an upgraded version of TOS: 1.02 (also known as TOS 1.2). Another early addition (after about 6 months) was an RF Modulator that allowed the machine to be hooked to a colour TV when run in its low or medium resolution (525/625 line 60/50 Hz interlace, even on RGB monitors) modes, greatly enhancing the machine's saleability and perceived value (no need to buy a prohibitively expensive, even if exceptionally crisp and clear, monitor). These models were known as the 520STM (or 520STM). Later F and FM models of the 520 had a built in double-sided disk drive instead of a single-sided one.
As originally released in the 520STE/1040STE:
- All of the features of the 520STFM/1040STFM
- Extended palette of 4,096 available colours to choose from
- BLiTTER chip for copy/fill/clear large data blocks in memory (max write rate of 4 MB/s)
- Hardware-support for horizontal and vertical fine scrolling and split screen (using the Shifter video chip)
- DMA sound chip with 2-channels stereo 8-bit PCM sound at 6.25/12.5/25/50 kHz and stereo RCA audio-out jacks (using enhancements to the Shifter video chip to support audio shifting)
- National LMC 1992 audio controller chip, allowing adjustable left/right/master volume and bass and treble EQ via a "Microwire" (3-bit serial) interface
- Memory: 30-pin SIMM memory slots (SIPP packages in earliest versions) allowing upgrades up to 4 MB Allowable memory sizes including only 0.5, 1.0, 2.0, 2.5 and 4.0 MB due to configuration restraints (however, 2.5 MB is not officially supported and has compatibility problems). Later 3rd-party upgrade kits allow a maximum of 14MB w/Magnum-ST, bypassing the stock MMU with a replacement unit and the additional chips on a separate board fitting over it.
- Ability to synchronise the video-timings with an external device so that a video Genlock device can be used without having to make any modifications to computer's hardware
- Analogue joypad ports (2), with support for devices such as paddles and light pens in addition to joysticks/joypads. The Atari Jaguar joypads and Power Pad joypads (gray version of Jaguar joypads marketed for the STE and Falcon) can be used without an adapter. Two standard Atari-style digital joysticks could be plugged into each analogue port with an adapter.
- TOS 1.06 (also known as TOS 1.6) or TOS 1.62 (which fixed some major backwards-compatibility bugs in TOS 1.6) in two socketed 128 kB ROM chips.
- Socketed PLCC 68000 CPU
The members of the ST family are listed below, in rough chronological order:
- Original model with 512 kB RAM, external power supply, no floppy disk drive. The early models had only a bootstrap ROM and TOS had to be loaded from disk.
- intended to be a 128 kB variant. Announced at the 1985 CES alongside the 520ST but never produced.
- early 520STs with 1 MB of RAM, but without floppy disk
- originally intended to be a 256 kB variant, but actually sold in small quantities in Europe with 512 kB. Used after the release of the 520ST+ to differentiate the cheaper 512 kB models from the 1 MB models
- a 520ST with a built-in modulator for TV output, 512 kB RAM.
- a 520STM with a newly redesigned motherboard in a larger case with a built-in floppy disk drive (in some cases a single sided drive only), 512 kB RAM.
- a 520STFM with 1 MB of RAM and a built-in double-sided floppy disk, but without RF modulator
- a 520STFM with 1 MB of RAM and a built-in double-sided floppy disk with RF modulator
- Mega ST (MEGA 1, MEGA 2, MEGA 4)
- redesigned motherboard with 1, 2 or 4 MB of RAM, respectively, in a much improved "pizza box" case with a detached keyboard. All MEGA mainboard have a PLCC socket for the Blitter chip and some early models did not include the BLiTTER chip. Included a real-time clock and internal expansion connector. Some early MEGA 2 had a MEGA 4 mainboard with half of the mem chip places unpopulated and these MEGA 2 can be upgraded by adding the additional DRAM chips and some resistors for the control lines. The MEGA 1 mainboards had a redesigned mem chip area and could not be upgraded in this way as there are only mem chip places for the 1 MByte DRAM chips.
- 520STE and 1040STE
- a 520STFM/1040STFM with enhanced sound, the BLiTTER chip, and a 4096-color palette, in the older 1040 style all-in-one case
- as 1040STE but with 4 MB of RAM. Never officially released except a small quantity of development units. Labels were sent out to dealers to affix to machines that had been upgraded to 4MB.
- Mega STE
- same hardware as 1040STE except for a faster 16 MHz processor, an onboard SCSI controller, additional faster RS232 port, VME expansion port, in the TT case
- a portable (but definitely not laptop) version of the ST. Originally designed to operate on 12 standard C cell flashlight batteries for portability, when Atari finally realized how quickly the machine would use up a set of batteries (especially when rechargeable batteries of the time supplied insufficient power compared to the intended alkalines), they simply glued the lid of the battery compartment shut, and soon discontinued the machine.
- ST BOOK
- a later portable ST, more portable than the STacy, but sacrificing several features in order to achieve this — notably the backlight, and internal floppy disk drive. Files were meant to be stored on a small amount (one megabyte) of internal flash memory 'on the road' and transferred using serial or parallel links, memory flashcards or external (and externally powered) floppy disk to a desktop ST once back indoors. The screen is highly reflective for the time, but still hard to use indoors or in low light, it is fixed to the 640 × 400 1-bit mono mode, and no external video port was provided. For its limitations, it gained some popularity, particularly amongst musicians.
Related systems 
- Atari TT030: new machine based on the Motorola 68030 processor running at 32 MHz, in yet another new case design with a detached keyboard. Capable of high screen resolutions with better colour palettes and addressing more memory, with optional onboard hard drive (slotting onto the base as a second, smaller box). Popular with CAD and DTP communities of the time for its sheer graphical capability (its 1280x960 high resolution display only recently having become a common size on modern PCs) and processing speed.
- Atari Falcon 030: another 68030 based (albeit only 16 MHz) machine like the TT, but in the STE-style case (yet again) with further upgrades to the graphics and sound, a Motorola 56000 DSP for CD-quality sound recording and processing, multitasking OS (on disk) and a LocalTalk port for networking. Last computer made by Atari.
- Atari ABAQ, or Atari Transputer Workstation: A standalone machine developed in conjunction with Perihelion Hardware, containing modified ST hardware and up to 17 transputers capable of massively parallel operations for tasks such as ray tracing.
There were also some unreleased prototypes: Falcon 040 (based on a Motorola 68040, new case and slots), ST Pad/STylus (A4 (Letter paper) sized pen-operated portable ST computer, handheld and with an unlit monochrome LCD screen derived from the ST Book, forerunner of modern tablet PCs).
- GE-Soft Eagle: TT clone but with 32 MHz system bus Article in SOS, June 1995
- Medusa 040, Medusa 060, Hades 040, Hades 060—3rd-party Falcon/TT compatible machines manufactured by Medusa Computer Systems .
- Milan Computersystems GbR MILAN I, MILAN II
- Firebee, a 264Mhz Freescale Coldfire CPU based Atari clone, designed and developed openly by the Atari Coldfire Project (ACP).
- Experiment-s, FPGA based implementation of Atari ST/STE and a prototype implementation of Atari ST/STE/Mega-ST/Mega-STE/Falcon.
- SF354: Single-sided double-density 3½ floppy drive (360 kB) with external power supply
- SF314: Double-sided double-density 3½ floppy drive (720 kB) with external power supply
- PS3000: Combined 12" Colour Monitor and 360k 3.5 Floppy Drive (SF354). Speaker. Manufactured by JVC in limited quantity (~1000), only a few working models remain.
- SM124: Monochrome monitor, 12" screen, 640 × 400 pixels, 70 Hz refresh
- SM147: Monochrome monitor, 14" screen, no speaker, replacement for SM124
- SC1224: Color monitor, 12" screen, 640 × 200 pixels plus speaker
- SC1425: Color monitor, 14" screen, One speaker on the left of screen, a jack to plug ear-listeners
- SC1435: Color monitor, 14" screen, stereo speakers, replacement for SC1224 (rebadged Magnavox 1CM135)
- SM195: Monochrome monitor, 19" screen for TT030. 1280 × 960 pixels. 70 Hz refresh
- SH204: External hard drive, 20 MB MFM drive, "shoe box" case made of metal
- SH205: External hard drive, Mega ST matching case, 20 MB MFM 3,5" (Tandon TM262) or 5.25" (Segate ST225) drive with ST506 interface (became later the Megafile 20)
- Megafile 20, 30, 60: External hard drive, Mega ST matching case, ACSI bus; Megafile 30 and 60 had a 5.25" RLL (often a Seagate ST238R 30 MByte or Seagate ST277R 60 MByte drive) with ST506 interface
- Megafile 44: Removable cartridge drive, ACSI bus, Mega ST matching case
- SLM804: Laser printer, connected through ACSI DMA port, used ST's memory and processor to build pages for printing
- SLM605: Laser printer, connected through ACSI DMA port, smaller than SLM805
See also 
- "Three Years with the ST". STart Magazine. summer 1988. Retrieved 2012-06-08.
- "Personal Computer News 110: Atari Advances – The Atari 520ST – Preview by Alan Turbull". June 1985. Retrieved 2012-11-07.
- "The Future of Atari Computing". STart Magazine. December 1989. Retrieved 2006-06-23.
- "AmigaOS". Archived from the original on 11 October 2007. Retrieved 2007-10-22.
- "Atari Is Shipping 520 ST Computer". The New York Times. 1985-07-10.
- "GUI Timeline". media.arstechnica.com.
- A.N.A.L.O.G. TCS #1 001 03/20/85 DRI SHIPS GEM: net.micro.atari: Google Groups. Groups.google.com (1985-03-11). Retrieved on 2013-04-22.
- "Utah Saints Interview". MusicTech.net. Retrieved 2012-03-20.
- "History of Amiga video". Youtube.com (2008-02-18). Retrieved on 2013-04-22.
- "Confidential Atari-Amiga Agreement" and "Afterthoughts: The Atari 1600XL Rumor". Archives.atarimuseum.com. Retrieved on 2013-04-22.
- Daniels, Jeffrey (Summer 1988). "3 Years With the ST". START Magazine (James Capparell). p. 22. Retrieved 2010-05-15.
- Chin, Kathy (1985-01-28). "Atari Announces Six New Computers". InfoWorld (IDG). pp. 1, 15, 20. Retrieved 2011-03-19.
- Cohen, Roger (1992-03-22). "A $78 Million Year: Steve Ross Defends His Paycheck". The New York Times.
- Jay G. Miner. Heartbone.com. Retrieved on 2013-04-22.
- Chin, Kathy (1985-01-28). "Atari Promises Software For ST". InfoWorld (IDG). p. 17. Retrieved 2011-03-19.
- Powell, Jack (October 1985). "ST Product News: First ST review". ANTIC (magazine) 4 (6). p. 26.
- Robert Anton Wilson, "Religion For the Hell of It", Hot Press, 1986
- "Bold plans for new Atari". InfoWorld. December 1984. Retrieved 2011-08-01.
- Dr T'S Kcs And Tiger Cub. Tamw.atari-users.net. Retrieved on 2013-04-22.
- White Town – Your Questions Answered!. Whitetown.co.uk. Retrieved on 2013-04-22.
- The Antic Cyber Graphics Software and the Pre-History of Autodesk 3D Studio and Discreet 3ds max. Asterius.com. Retrieved on 2013-04-22.
- The Antic Cyber Graphics Software and the Pre-History of Autodesk 3D Studio and Discreet 3ds max. Asterius.com. Retrieved on 2013-04-22.
- Dinner with Tom Hudson. rand.com (17 January 2007).
- The People of ANALOG. Analog.klanky.com. Retrieved on 2013-04-22.
- The Antic Cyber Graphics Software and the Pre-History of Autodesk 3D Studio and Discreet 3ds max. Asterius.com (2002-03-01). Retrieved on 2013-04-22.
- Bisson, Giselle. Getting Down To Business. START Vol. 2 No. 6, Special issue #3. Atarimagazines.com. Retrieved on 2013-04-22.
- Motorola Literature Distribution, Phonenix, AZ (1992). M68000 Family Programmer's Reference Manual. [Motorola]. p. 1–1. ISBN 0-13-723289-6.
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