Atari ST

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.[8]

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".[9]

After leaving Commodore International in January 1984, Jack Tramiel formed Tramel Technology, Ltd. with his sons and other ex-Commodore employees and, in April, began planning a new computer. The company initially considered the National Semiconductor NS32000 microprocessor but was disappointed with its performance.[10][11] This started the move to the 68000. The lead designer of the Atari ST was ex-Commodore employee Shiraz Shivji, who had previously worked on the Commodore 64's development.[12][13]

Atari in mid-1984 was losing about a million dollars per day.[14] Interested in Atari's overseas manufacturing and worldwide 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 Tramel Technology, Commodore responded by filing lawsuits against four former engineers for theft of trade secrets.

The Tramiels did not purchase the employee contracts when they bought the assets of Atari Inc., so one of their first acts was to interview Atari Inc. employees to decide whom to hire at what was essentially a brand new company. At the time of the purchase of Atari Inc's assets, there were roughly 900 employees remaining from a high point of 10,000. After the interviews, approximately 100 employees were hired to work at Tramel Technology, which soon changed its name to Atari Corporation.

At one point a custom sound processor called AMY was a planned component for the new ST computer design, but the chip needed more time to complete, so AMY was dropped in favor of an off-the-shelf Yamaha sound chip.[15]

It was during this time in late July/early August that Leonard Tramiel 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).

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 (OS) 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.[10][16]

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 two years, far too long for their needs. Another possibility was Digital Research, who was 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.[10]

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" (a.k.a. The Operating System) for the Atari ST line of computers. The name came from the original designer and developer, Jason Loveman.[17]

GEM was based on CP/M-68K, essentially a direct port of CP/M to the 68000. By 1985, CP/M was becoming increasingly outdated; it did not support sub-directories, for example. 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 Atari TOS (The Operating System and colloquially known as the Tramiel Operating System). This gave the ST a fast, hierarchical file system, essential for hard drives, plus programmers had function calls similar to IBM PC DOS. The character set is based on codepage 437.

Besides the original TOS operating system, a number of third-party OSes were developed for, or ported to, the Atari ST. Among Unix clones, Idris, Minix had an Atari ST port and the Mint OS was developed specifically for the Atari ST.

Atari ST print advertisements stated "America, We Built It For You", and quoted Atari president Sam Tramiel: "We promised. We delivered. With pride, determination, and good old ATARI know how".[28] Although Atari was out of cash, sales of its 8-bit computers were "very, very slow" according to Jack Tramiel, and employees feared that he would shut the company down, the 520ST shipped during spring 1985 to the press, developers, and user groups, and in early July 1985 for general retail sales, saving the company.[10][1][29] By November the company stated that it had sold more than 50 thousand 520STs, "with U.S. sales alone well into five figures".[30] The machine had gone from concept to store shelves in a little under a year.

Atari had intended to release versions with 128 KB and 256 KB of RAM as the 130ST and 260ST respectively. However, the ST initially shipped with TOS on disk, requiring 206 KB RAM when loaded, leaving little or no room for applications. The 260ST did make its way into Europe on a limited basis.[31] Early models were designed with six ROM sockets that allowed easy upgrading to the future ROM-based TOS.[32] These became available only a few months later and were included in all new machines as well as being available as an upgrade for 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 520ST^M. ST systems before the Mega ST range have no battery-backed clock, although third-party boards that went between the 6301 socket and the 6301 chip which was used for the keyboard and clock could be connected to a rechargeable battery pack to provide a battery-backed clock.[33]

Atari 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.

The face of J.R. "Bob" Dobbs

A limited set of GEM fonts were included in the ROMs, including the standard 8x8 pixel graphical character set for the ST. It contained four unusual characters which can be placed together in a square, forming a facsimile of the face of J. R. "Bob" Dobbs (the figurehead of the Church of the SubGenius).[34]

The ST was less expensive than most machines, including the Macintosh Plus, and tended to be faster than most.[35] 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.

The Atari 520ST+

The original 520ST case design was created by Ira Velinsky – Atari's chief Industrial Designer.[36] The ST is wedge-shaped, featuring bold angular lines and a series of grilles cut into the rear for airflow. The keyboard has soft tactile feedback and rhomboid-shaped function keys across the top. The 520ST is an all-in-one unit, similar to earlier home computers like the Commodore 64, but with a larger keyboard with cursor keys and a numeric keypad.

The 520ST uses an external power brick.

Atari 520ST ports

Atari ST mouse (2000)

The 520ST features a large number of ports mounted at the rear of the machine that remained largely unchanged over the ST's history.

• Standard ports:
  • RS-232c serial port (DB25 male, operating as basic 9-conductor DTE)
  • Centronics printer port (DB25 female, officially compliant only with the most basic unidirectional standard with a single, "Busy" input line; unofficially offering some bidirectional capabilities)
  • Atari joystick ports (DE-9 male) for the mouse and game controllers
  • 2 MIDI ports (5-pin DIN, "IN" and "OUT")[37]
• ST-specific ports:
  • Monitor port (custom 13-pin DIN, 12 of the pins in a rectangular pattern, carrying signals for both RGB and monochrome monitors, monophonic audio and, in later models, composite video)
  • ACSI (similar to SCSI) DMA port (custom-sized 19-pin D-sub, for hard disks and laser printers, capable of up to 2 MByte/s with efficient programming)
  • Floppy port (standard – if rare – 14-pin DIN, listed as operating at 250 kbit/s)
  • ST cartridge port (double-sided 40-contact edge connector socket, for 128 KB ROM cartridges)

Because of its bi-directional design, the Centronics printer port can be used for joystick input, and several games make use of available adaptors that plugged into the printer socket, providing two additional 9-pin joystick ports.

The ST supports a monochrome or color monitor. The color hardware supports two different resolutions, 320 × 200 with 16 out of 512 colors, or 640 × 200 with 4 out of 512 colors. The monochrome monitor was less expensive and has a single resolution of 640 × 400 at 71.25 Hz. The attached monitor determines available resolutions, so software either supports both types of monitors or only works with one.[32] Color is required by a majority of games.

Atari initially used single-sided 3.5 inch disk drives that could store up to 360 kB. Later drives were double-sided and stored 720 kB. Some commercial software, particularly games, shipped by default on single-sided disks, even supplying two 360kB floppies instead of a single double-sided one, for fear of alienating early adopters.

Another sticking point with the ST's floppy drives was that, while double-sided drive equipped STs could happily read discs formatted under MS-DOS on IBM PCs, PCs could not themselves read Atari disks, because the initial versions of TOS could recognise, read, and write to – but not themselves create – discs in the same particular specification used and indeed demanded by MS-DOS because of differences in the layout of data on track 0. Atari ST native format uses 5 sectors for FAT12 entries, while MSDOS uses 3 sectors for double sided floppies and 2 sectors for single sided floppies. Although the number of sectors for the FAT12 entries is included on track 0, MSDOS ignores it and assumes 2 (single sided) or 3 sectors (double sided). The Atari ST uses that info, so it can operate with floppies formatted either way. Achieving successful data interchange between the two platforms normally meant using floppies formatted by MSDOS, or by third party formatting utilities that were later released for the Atari ST. Conversion utilities such as MOSDOS.TOS could convert a native ST formatted floppy to a MSDOS compatible floppy. Other utilities allowed for transfer with unusual formats, such as the Commodore Amiga. Atari's own version 1.4 (and later) TOS upgrades, switched to formatting MSDOS compatible floppies.

Atari 1040ST^F

Atari later upgraded the basic design in 1986 with the 1040ST^F (also written STF). The machine is 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. The joystick/mouse ports, formerly on the right side of the machine where the disk drive now sat, were moved to a 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;[6][10] Compute! noted that, in fact, the 1040ST was the first computer to break the $2500/megabyte price barrier.[38] 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.[39]

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 lack the 'M' modulator that allows a TV to be used and will therefore only work with a monitor.

Initial sales were strong, especially in Europe where Atari sold 75% of its computers. Germany became Atari's strongest market,[10] with small business owners using them for desktop publishing and CAD.

To address this growing market segment, Atari introduced the ST1 at Comdex in 1986. Renamed the Mega, it includes a high-quality detached keyboard, a stronger case to support the weight of a monitor, and an internal bus expansion connector. A 20 MB hard drive could be purchased as an option and stacked below or above the main case. 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.

A custom blitter coprocessor speeds the performance of some graphics operations, but it is not included in all models. Developers wanting to use it have to detect its presence in their programs. Properly written applications using the GEM API automatically make use of the blitter.

In late 1989, Atari released the 520ST^E and 1040ST^E (also written STE), enhanced version of the ST with improvements to the multimedia hardware and operating system. It features an increased color palette of 4,096 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 blitter co-processor (stylized as "BLiTTER") which can quickly move large blocks of data (most particularly, graphics data) around in RAM. The STE was the first Atari with PCM audio; using a new chip, it added the ability to play back 8-bit (signed) samples at 6258 Hz, 12517 Hz, 25033 Hz and even 50066 Hz, via DMA (Direct Memory Access). The channels are arranged as either a mono track or a track of LRLRLRLR... bytes. RAM was now much more simply upgradable via SIMMs.

Two enhanced joystick ports were added (two normal joysticks can be plugged into each port with an adapter), 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.

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. Furthermore, even having a joystick plugged in would sometimes cause strange behavior with a few applications (such as the WYSIWYG word-processor application 1st Word Plus). Very little use was made of the extra features of the STE: STE-enhanced and STE-only software was rare.

The last STE machine, the Mega STE, is 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-inch 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.

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.

The Falcon case closely resembled that of the ST^F and ST^E, albeit with a slightly altered colour scheme.

The final ST computer is 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 is capable of using 32-bit memory, the Falcon uses a 16-bit bus which affects 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 ST^F and ST^E. 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 discontinued by Atari the following year. In Europe, C-Lab licensed 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). The C-Lab Falcons were also imported to the US by at least some Atari dealers.

The ST has 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, contains a "Multi-Program Environment" that allows 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.[48]

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 combines the sample playing abilities of a tracker with conventional music notation (which was usually only found in MIDI software) is called Quartet (after its four-note polyphonic tracker, which displays one monophonic stave at a time on color 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 features a sound sampler that cleverly uses the ST cartridge port to read in parallel from the cartridge port from the ADC. For output of digital sound, it uses the on-board frequency output, sets it to 128 kHz (inaudible) and then modulates the amplitude of that.

Another program that had success on the ST platform is 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 macOS along with the other Passport product, the notation program Encore, which is as of 2013 marketed and maintained by a new iteration, Passport Music Software, LLC.

Degas Elite by Batteries Included

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, H&DBase, Informer II, DB Master One, SBT Database Accounting Library (dLedger, dInvoice, dOrder, dPurchases, and dPayables), Superbase Personal, Superbase Professional, Tracker ST, Zoomracks 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)[49] featured advanced features such as 3D design and animation. One paint program, Spectrum 512, uses the ST's rapid palette switching ability to expand the maximum number of colors to be displayed on-screen at once to 512[49] (up to 46 in each scan line.

3D computer graphics applications (like Cyber Studio CAD-3D, which author Tom Hudson would later develop into Autodesk 3D Studio[50][51]), brought 3D modelling, sculpting, scripting, and computer animation 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 color (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.[49]

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[52] copyright and trademark. It does not feature the Atari ST's GEM graphical user interface but, instead, features an application specific graphical user interface and widget framework which he developed using, in part, the Neochrome paint program.

The 520 ST came bundled with both Digital Research Logo and Atari ST BASIC.[53] Third-party BASICs with better performance were eventually available: HiSoft BASIC, GFA BASIC, FaST BASIC, DBASIC, LDW BASIC, Omikron BASIC, BASIC 1000D and STOS. In the later years of the Atari ST, Omikron Basic was bundled with it in Germany.

The initial development kit from Atari included a computer and manuals. The $5,000 cost discouraged many from developing software for the ST. Later, the Atari Developer's Kit consisted of software and manuals (but 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 third-party Megamax C development package reduced the cost of entry to $200.

Other development tools include 68000 assemblers (MadMac from Atari, HiSoft Systems's Devpac, TurboAss, GFA-Assembler), Pascal (OSS Personal Pascal, Maxon Pascal, PurePascal), Modula-2, C compilers (Lattice C, Pure C, Megamax C, GNU C, Aztec C, AHCC), LISP, Prolog, and others.

The ST enjoyed success in gaming due to the 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.

The realtime pseudo-3D role-playing video game Dungeon Master, was developed and released first on the ST, and was the best-selling software ever produced for the platform.[54] Simulation games like Falcon and Flight Simulator II made use of the ST's graphics, as did many arcade ports. Proto first person shooter MIDI Maze, uses the MIDI ports to connect up to 16 machines for networked deathmatch play. The critically acclaimed Another World was originally released for ST and Amiga in 1991 with the engine developed on the ST and the rotoscoped animations created on the Amiga. Games simultaneously released on the Amiga that didn't use the Amiga's superior graphics and sound capabilities were often accused by video game magazines of simply being ST ports.

Garry Kasparov became the first player to register the commercial ChessBase, a popular commercial database program produced for storing and searching records of games of chess. The first version was built for Atari ST with his collaboration in January 1987.[55] In his autobiography Child of Change, he regards this facility as "the most important development in chess research since printing."

Spectre GCR lets the ST emulate the Macintosh. There were also MS-DOS emulators released in the late 1980s. PC-Ditto came in two versions: software-only, and a hardware version that plugs into the cartridge slot or kludges internally. After running the PC-Ditto software, an MS-DOS boot disk is required to load the system. Both allow users to run MS-DOS programs in CGA mode, though much more slowly than on an IBM PC. Other options are the PC-Speed (NEC V30), AT-Speed (Intel 80286) and ATonce-386SX (Intel 80386sx) hardware emulator boards.

As originally released in the 520ST:

• CPU: Motorola 68000 16-/32-bit CPU[64] @ 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 color and mono, 13-pin DIN), extra disk drive port (14-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 (TOS meaning The Operating System) with the 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 ST^Fs, 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 allows the machine to be hooked to a color 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 520ST^M (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 520ST^E/1040ST^E:

• All of the features of the 520STFM/1040STFM
• Extended palette of 4,096 available colors to choose from
• BLiTTER chip to copy/fill/clear large data blocks in memory (with a max write rate of 4 Mbytes/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 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 third-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 ST^E 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 130ST was intended to be a 128 KB variant. It was announced at the 1985 CES alongside the 520ST but never produced. The 4160ST^E was a 1040ST^E, but with 4 MB of RAM. A small quantity of development units were produced, but the system was never officially released. Atari did produce a quantity of 4160STE metallic case badges which found their way to dealers, so it's not uncommon to find one attached to systems which were originally 520/1040STE. No such labels were produced for the base of the systems.

Atari Transputer Workstation is 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.

Following Atari's exit from the computer market, both Medusa Computer Systems and Milan Computer manufactured Atari Falcon/TT-compatible machines that used 68040 and 68060 processors. The FireBee is an Atari ST/TT clone based on the Coldfire processor. The GE-Soft Eagle is a 32 MHz TT clone.[65]