During this gestation the home computer era began in earnest in the form of the Apple II family, Commodore PET and TRS-80—what Byte Magazine would later dub the "1977 Trinity". Ray Kassar, the then-new CEO of Atari from Warner Communications, wanted the new chips to be used in a home computer to challenge Apple. In order to adapt the machine to this role, it would need to support character graphics, include some form of expansion for peripherals, and run the then-universal BASIC programming language.
Management identified two sweet spots for the new computers, a low-end version known as Candy, and a higher-end machine known as Colleen (named after two attractive Atari secretaries). The primary difference between the two models was marketing; Atari marketed Colleen as a computer, and Candy as a game machine (or hybrid game console). Colleen would include slots for RAM and ROM, a second 8 KB cartridge slot, monitor output and a full keyboard, while Candy used a plastic "membrane keyboard" and internal slots for memory (not user upgradable).
At the time, the Federal Communications Commission (FCC) mandated that signal leakage in the television frequency range had to be extremely low. As the Atari machines had TV circuitry inside them, they were subject to this rule and needed to be heavily shielded. Both the 400 and 800 were built around very strong cast aluminum shields forming a partial Faraday cage, with the various components screwed down onto the internal framework. This had the advantage of producing an extremely study computer, although at the disadvantage of being expensive and complex. The FCC ruling also made it difficult to have any sizable holes in the case, which eliminated expansion slots or cards that communicated with the outside word via their own connectors. Instead, Atari designed the Serial Input/Output (SIO) computer bus, a daisy-chainable system that allowed multiple devices to connect to the computer through a single shielded connector. Although the 800 included internal slots, they were reserved for ROM and RAM memory modules.
Atari had originally intended to port Microsoft BASIC to the machine, as had most other vendors, intending to supply it on an 8 KB ROM cartridge. However the existing 6502 version from Microsoft was 12 KB, and all of Atari Inc.'s attempts to pare it down to 8 KB failed. Eventually they farmed out the work to a local consulting firm, who recommended writing their own version from scratch, which was eventually delivered as Atari BASIC.
The machines were announced in late 1978 as the 400 and 800, although they weren't widely available until November 1979, much closer to the original design date. The names originally referred to the amount of memory, 4 KB RAM in the 400 and 8 KB in the 800. However by the time they were released the prices on RAM had started to fall, so the machines were instead both released with 8 KB. Originally the 800 shipped with 8 KB, but as memory prices continued to fall Atari eventually supplied the machines fully expanded to 48 KB, using up all the slots. Overheating problems with the memory modules eventually led Atari Inc. to remove the modules casings, leaving them as "bare" boards. Later, the expansion cover was held down with screws instead of the easier to open plastic latches.
The Atari 400, despite its membrane keyboard and single internal ROM cartridge slot, outsold the more feature rich Atari 800 by some margin. Because of this, developers were generally unwilling to use the 800-only right cartridge slot.
The 400 and 800 were complex and expensive machines to build, consisting of multiple circuit boards mostly enclosed by massive die-cast aluminum shielding. Additionally, the machine was designed to add RAM only through cards, though it soon shipped fully expanded right from the factory. At the same time the 400 didn't compete technically with some of the newer machines appearing in the early 1980s, which tended to ship with much more RAM and an upgraded keyboard.
Another major change was the introduction of the FCC ratings specifically for digital devices in homes and offices. One of the ratings, known as Class B, mandated that the device's RF emissions were to be low enough not to interfere with other devices, such as radios and TVs. Now computers needed just enough shielding to prevent interference (both ways), not prevent any emissions from leaking out. This requirement enabled lighter, less expensive shielding than the previous 400 and 800 computers.
In 1982 Atari started the Sweet 8 (or "Liz NY") and Sweet 16 projects to take advantage of these changes. The result was an upgraded set of machines otherwise similar to the 400 and 800, but much easier to build and less costly to produce. Whereas the previous machines had individual circuit boards mounted inside and outside the internal shield, in the new design a single board supported all of the circuitry and the much thinner shielding was attached to it. Improvements in chip making allowed a number of chips in the original systems to be condensed into one. Atari also ordered a custom version of the 6502, the "C" model, which added a single pin that allowed four support chips to be removed. An external expansion chassis was also supported.
Like the earlier machines, the Sweet 8/16 was intended to be released in two versions as the 1000 with 16 KB and the 1000X with 64 KB; RAM was still expensive enough to make this distinction worthwhile.
When the machines were actually released there was only one version, the 1200XL, an odd hybrid of features from the Sweet 8/16 projects. Notable features were 64 KB of RAM, built-in self test, redesigned keyboard (featuring four function keys and a HELP key), and redesigned cable port layout. In general terms the 1200XL most closely matched the "high end" Sweet 16 concept.
However the 1200XL also included a number of missing or poorly implemented features. The expansion connector from the original 1000X design was left off, making the design rely entirely on SIO again. Frustrating this was the fact that the +12V pin in the SIO port was left unconnected; only +5V power was available although some devices made use of the +12V line. An improved video circuit provided more chroma for a more colorful image, but the chroma line was not connected to the monitor port, the only place that could make use of it. Even the re-arrangement of the ports made some joysticks and cartridges difficult or impossible to use. Changes made to the operating system to support the new hardware also resulted in compatibility problems with some older software that did not follow published guidelines. There was no PAL version of the 1200XL.
The 1200XL ended up with functionality similar to the existing 800, but at a hefty price point. For all of these reasons the 1200XL sold poorly. There is an often-repeated story, perhaps apocryphal, that 800 sales shot up after the release of the 1200XL, as existing owners tried to snap them up before they disappeared. Released in late 1982, the machine was discontinued in 1983.
By this point in time Atari Inc. was involved in what would soon develop into a full-blown price war when Jack Tramiel of Commodore International was attempting to undercut his old enemy Texas Instruments. TI had undercut Commodore's calculator business only a few years earlier, almost driving him from the market, but this time Tramiel's supply was stronger than TI's, and he could turn the tables. Although Atari Inc. had never been a deliberate target of Tramiel's wrath, they, along with the rest of the market, were dragged into "his" price war in order to maintain market share.
The timing was particularly bad for Atari Inc.; the 1200XL was a flop, and the earlier machines were too expensive to produce to be able to compete at the rapidly falling price points. The solution was to replace the 1200XL with a machine that users would again trust, while at the same time lowering the production costs to the point where they could compete with Commodore.
Starting with the 1200XL design as the basis for a new line, Atari Inc. engineers were able to add a number of new IC's to take over the functions of many of those remaining in the 1200XL. While the 1200XL fit onto a single board, the new designs were even smaller, simpler, and as a result much less expensive. To reduce cost even further, manufacturing of a new series of machines was set up in the far east.
Several versions of the new design, the 600XL, 800XL, 1400XL and 1450XLD were announced at the 1983 Summer CES. The machines had Atari BASIC built into the ROM of the computer and a Parallel Bus Interface (PBI) at the back that allowed external expansion. The machines looked similar to the 1200XL, but were smaller back to front, the 600 being somewhat smaller than the 800 front-to-back (similar to the original Sweet 8 project). The 1400 and 1450 both added a built-in 300 baud modem and a voice synthesizer, and the 1450XLD also included a built-in double-sided floppy disk drive in an enlarged case.
Problems with the new production lines delayed the entry of the machines onto the market. Originally intended to replace the 1200XL in mid-83, the machines did not arrive until late in 1983, and far fewer than anticipated were available during the 1983 Christmas season. Nonetheless, the 800XL was the most popular computer sold by Atari Inc.. The 1400XL and the 1450XLD had their delivery dates pushed back, first by the priority given to the 600XL/800XL, and later by the 3600 System. In the end the 1400XL was eventually canceled outright, and the 1450XLD so delayed that it would never ship.
Prototypes which never made it to market include the 1600XL, 1650XLD, and 1850XLD. The 1600XL was to have been a dual processor model capable of running 6502 and 80186 code. This was canceled when James J. Morgan became CEO and wanted Atari to return to its video game roots. The 1650XLD would have been 6502-based in a 1400XLD case. The 1850XLD was to have been based on the Amiga Lorraine (later to become the Commodore Amiga). These models were canceled when Jack Tramiel took over Atari and changed the XL series development into the XE series. (Of course, the new Atari swapped the Amiga system for the ST system. (See Atari ST, Amiga Contract).
By late 1983 the price war that had started the year before was now reaching a crescendo. Although the 600/800 were well positioned in terms of price and features, their entry into the market was so delayed that Commodore dramatically outsold them over the '83 Christmas season. Combined with the simultaneous effects of the video game crash of 1983, Atari Inc. was soon losing millions of dollars a day. Their owners, Warner Communications, became desperate to sell off the division.
Although Commodore emerged intact from the computer price wars, fighting inside Commodore soon led to Jack Tramiel's ousting. Looking to re-enter the market, he soon purchased Atari Inc.'s consumer division from Warner for an extremely low price.
Jack Tramiel's Atari Corporation produced the final machines in the 8-bit series, which were the 65XE and 130XE (XE stood for XL-Expanded). They were announced in 1985, at the same time as the initial models in the Atari ST series, and resembled the Atari ST. Originally intended to be called the 900XLF, the 65XE was functionally equivalent to the 800XL minus the PBI connection. The 65XE (European version) and the 130XE had the Enhanced Cartridge Interface (ECI), a semi-compatible variant of the Parallel Bus Interface (PBI). The 130XE shipped with 128 KB of memory, accessible through bank-selection.
An additional 800XE was available in Europe (mostly Eastern Europe), which was essentially a 65XE repackaged in order to ride on the popularity of the original 800XL in Europe. Unfortunately, the 65XE and 800XE machines sold in Eastern Europe had a buggy GTIA chip, specifically those machines made in China in 1991.
Finally, with the resurgence of the gaming industry brought on by Nintendo, Atari Corp. brought out the XE Game System (XEGS), released in 1987. The XE Game System was sold bundled with a detachable keyboard, a joystick and a light gun (XG-1), and a couple of game cartridges (Bug Hunt and Flight Simulator II). The XE Game System was essentially a repackaged 65XE, and was compatible with almost all Atari 8-bit software and hardware as a result. Bad marketing and a lack of newer releases hampered sales.
The ANTIC is primarily responsible for drawing the "background" of the graphics screen, as well as text. ANTIC then passes off the video data through the GTIA, which adds color and drew sprites (which Atari called "players" and "missiles"). The combination leads to oddities such as the ability to invert all the text on the screen by changing a value in memory. The character set is easily redirected by changing an ANTIC register, allowing the user to create their own character sets with relative ease.
The CTIA/GTIA receives graphics information from ANTIC and also controls sprites (known at the time as "Player/Missile Graphics"), collision detection, priority control and color-luminance (brightness) control to all objects (including DMA objects from ANTIC). CTIA/GTIA output them as separate digital luminance and chrominance signals, which are mixed to form an analogue composite video signal.
During the lifetime of their 8-bit series, Atari released a large number of peripherals. These included:-
Atari's peripherals used the proprietary SIO port, which allowed them to be daisy chained together into a single string; a method also used later in Commodore's home computers from the VIC-20 onwards. These "intelligent" peripherals were more expensive than the standard IBM PC devices, which did not need the added SIO electronics.
The Atari 8-bit computers came with an operating system built into the ROM. The Atari 400/800 had the following:
The XL/XE Atari 8-bit models all had OS revisions due to added hardware features and changes. But this created compatibility issues with some of the older software. Atari responded with the Translator Disk, a floppy disk which loaded the older 400/800 Rev. B or Rev. A OS into the XL/XE computers.
The XL/XE models also came with built-in Atari BASIC. Early models came with the notoriously buggy revision B. Later models used revision C.
The standard Atari OS only contained very low-level routines for accessing floppy disk drives. An extra layer, a disk operating system, was required to assist in organizing file system-level disk access. This was known as Atari DOS, and like most home computer DOSes of the era, had to be booted from floppy disk at every power-on or reset. Unlike most DOSs, Atari DOS was entirely menu driven.
Amongst the many pieces of software released for the 8-bit Atari computers, a large number of programming languages were implemented, including:-
It should be noted that these were only the modes the OS setup by default. As described above, the ANTIC chip used a display list and other settings to create these modes. The actual hardware could by programmed to display up to 384 pixels wide by putting the hardware in wide or overscan mode and up to 240 pixels tall by creating a custom display list.
Due to the 8-bit Ataris' flexibility, it was possible (with clever programming) to create a number of software-driven pseudo-"modes" beyond those directly supported in hardware. These included pseudo-256-color 80x192 modes and 80x24 character displays.