Atari 8-bit family
Encyclopedia
The Atari 8-bit family is a series of 8-bit
home computer
s manufactured from 1979 to 1992. All are based on the MOS Technology
6502
CPU
and were the first home computers designed with custom coprocessor chips. Over the following decade several versions of the same basic design were released, including the original Atari 400 and 800 and their successors, the XL and XE series of computers. Overall, the Atari 8-bit computer line was a commercial success, selling two million units through its major production run between late 1979 and mid-1985, a total of around 4 million units.
as soon as the Atari 2600
games console was released in late 1977. The engineering team from Atari Grass Valley Research Center (originally "Cyan Engineering") felt that the 2600 would have about a three year lifespan before becoming obsolete. They started "blue sky" designs for a new console that would be ready to replace it around 1980, three years after the 2600's introduction. What they ended up with was essentially a "corrected" version of the 2600, fixing its more obvious flaws. The newer design would be faster than the 2600, have better graphics, and would include much better sound hardware. Work on the chips for the new system continued throughout 1978 and primarily focused on much-improved video hardware known as the Color Television Interface Adaptor, or CTIA.
During this gestation the home computer era began in earnest in the form of the TRS-80
, Commodore PET
, and Apple II family—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 peripheral
s, and run the then-universal BASIC programming language.
The need for character graphics led to the introduction of the ANTIC
, a co-processor that ran in concert with the CTIA to provide graphics. Like the earlier TIA of the 2600, the CTIA was designed to produce sprites
and nothing else. ANTIC was built to generate conventional bitmap graphics
and characters, providing a number of different modes with varying color support and resolution. ANTIC and CTIA worked in concert to produce the complete display.
Management identified two sweet spot
s 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
(including 2 more pins for separate luma and chroma) and a full keyboard, while Candy used a plastic "membrane keyboard
" and internal slots for memory (not user upgradeable).
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 machines were built around very strong cast aluminum shields forming a partial Faraday cage
, with the various components screwed down onto this internal framework. This had the advantage of producing an extremely sturdy 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 world 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. What internal slots existed were reserved for ROM and RAM 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's attempts to pare it down to 8 KB failed. Eventually they farmed out the work to a local consulting firm, Shepardson Microsystems
, 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 were not 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. As memory prices continued to fall Atari eventually supplied the 800 fully expanded to 48 KB, using up all the slots. Overheating problems with the memory modules eventually led Atari to remove the module's 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.
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. This reduction in complexity was helped by improvements in chip making since the original machines were released, allowing a number of separate chips in the original systems to be condensed into one. Atari also ordered a custom version of the 6502, initially labeled "6502C" but eventually known as SALLY to differentiate it from a standard 6502C, which added a single pin that allowed four support chips to be removed. The SALLY was incorporated into late-production 400/800 machines, all subsequent XL/XE machines and Atari 5200/7800 game systems.
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. In order to support expansion for high-end systems, similar to the card slots used in the Apple II or S-100 machines, the 1000 series also supported the Parallel Bus Interface (PBI), a single expansion slot on the back of the machine. An external chassis could be plugged into the PBI, supporting card slots for further expansion.
However the 1200XL also included a number of missing or poorly implemented features. The PBI 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.
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. The machine was discontinued in 1983. There was no PAL version of the 1200XL.
By this point in time Atari 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 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; 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 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. But by this point, in early 1983, the price war rapidly drove prices downward. Atari, attempting to beat this downward pressure, took the opportunity to move production of the new machines to the far east, where they could be produced for even lower costs.
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 the 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.
However, the production move ran into unexpected delays. Originally intended to replace the 1200XL in mid-83, the machines did not arrive until late in 1983. Although the 600/800 were well positioned in terms of price and features, during the critical Christmas season they were available only in small numbers while the Commodore 64
was widely available. Although the 800XL would be the most popular computer sold by Atari, it was unable to defend Atari's marketshare, and the race to the bottom
gutted their profits. Combined with the simultaneous effects of the video game crash of 1983
, Atari was soon losing millions of dollars a day. Their owners, Warner Communications
, became desperate to sell off the division.
Through this process 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. Other 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, while the 1650XLD was a similar machine in the 1450XLD case. These were canceled when James J. Morgan
became CEO and wanted Atari to return to its video game roots. 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. The new Atari scrapped plans for the Amiga-based 1850XLD system for the Atari ST
system.
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 consumer division from Warner for an extremely low price.
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 visually 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), which was electronically almost compatible with the Parallel Bus Interface (PBI), but physically smaller, since it was located next to the standard 400/800-compatible Cartridge Interface and provided only those signals that did not exist in the latter; ECI peripherals were expected to plug into both the standard Cartridge Interface and the ECI port. 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.
On January 1, 1992, Atari corp. officially dropped all remaining support of the 8-bit line.
s that can be user-controlled via memory set/get instructions running on the 6502. For example, the GTIA uses a series of registers to select colors for the screen; these colors can be changed by inserting the correct values into its registers, which are mapped into "memory"
that is visible to the 6502. Some parts of the system also use some of the machine's RAM as a buffer, notably the ANTIC's display buffer and its Display List (essentially a small program written in the chip's simple machine language that tells ANTIC how to interpret that data and turn it into a display), as well as GTIA's sprite information. These features enable the computer to perform many functions directly in hardware, such as smooth background scrolling, that would need to be done in software in most other computers of the time.
is a microprocessor which processes display instructions. A complete sequence of instructions is known as a Display List. Each instruction describes how a single "line" on the screen is to be displayed (specifying one of several character or graphics modes available), where it is displayed, if it contains interrupts, if fine scrolling is enabled or not, and optionally where to load data from memory (text or graphics information). Since each line can be programmed individually, this feature enables the programmer to create displays made up of mixed graphics and text, as well as different graphics modes on the screen at once. It also enables the machine to quickly "scroll" the screen vertically or horizontally by means of a single memory write. ANTIC reads this Display List and the display data using DMA (Direct Memory Access), then translates the result into electrical data for GTIA to process. This process is performed without any CPU intervention.
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 draws 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.
, is responsible for reading the keyboard, generating sound and serial communications (in conjunction with the PIA). It also provides timers, a random number generator (for generating acoustic noise
as well as random numbers), and maskable interrupts. POKEY has four semi-independent audio channels, each with its own frequency, noise and volume control. Each 8-bit channel has its own audio control register which select the noise content and volume. For higher sound resolution (quality), two of the audio channels can be combined for more accurate sound (16-bit). The name POKEY comes from the words "POtentiometer" and "KEYboard", which are two of the I/O devices that POKEY interfaces with (the potentiometer is the mechanism used by the paddle
). This chip is actually used in several Atari arcade machines of the 80s, including Missile Command
and Asteroids Deluxe, among others.
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 chain
ed together into a single string. 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 the Atari BASIC
ROM built in, which could be disabled at startup by holding down the silver OPTION key to the right of the keyboard. Early models came with the notoriously buggy revision B. Later models used revision C.
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.
Several third-party replacement DOSes were also available, sometimes quite advanced, such as SpartaDOS X
.
More recently, cross platform development tools (most commonly run on PC
s), have become popular for retrocomputing
software development.
While the ANTIC and GTIA chips allowed a variety of graphics modes to be combined, and different playfield widths to be used, the Atari's Operating System provided a basic set of graphics modes. In most cases, these were exposed to Atari BASIC via the "GRAPHICS" command, and to some other languages, via similar system calls.
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 be 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.
on PAL and NTSC televisions is very different, as is the update speed and resolution, and so often they would display well on European systems and awfully on US ones, or vice versa. For the same reason they may not display well – or display rather too well – on simulators.
It was also possible by using the display list to display far more than the usual number of sprites on the screen, with more colours than available. This is done by beginning and ending instructions referencing the 'player missile graphics' on separate display list lines. Modifying these values allowed the programmer to move the sprites around and change their colours 'on the fly'. The same technique could be employed to display far more colours than seemingly allowed in any particular graphics mode, which could be mixed and altered at will.
Because the screen memory could be accessed by two pointers and relocated anywhere in available memory, it was also extremely easy to implement hardware scrolling and page flipping to enable easy game design and programming.
There are many examples of demo programs available on the internet, displaying these and other features which outperform other 8 bit machines of the time.
8-bit
The first widely adopted 8-bit microprocessor was the Intel 8080, being used in many hobbyist computers of the late 1970s and early 1980s, often running the CP/M operating system. The Zilog Z80 and the Motorola 6800 were also used in similar computers...
home computer
Home computer
Home computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...
s manufactured from 1979 to 1992. All are based on the MOS Technology
MOS Technology
MOS Technology, Inc., also known as CSG , was a semiconductor design and fabrication company based in Norristown, Pennsylvania, in the United States. It is most famous for its 6502 microprocessor, and various designs for Commodore International's range of home computers.-History:MOS Technology, Inc...
6502
MOS Technology 6502
The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...
CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
and were the first home computers designed with custom coprocessor chips. Over the following decade several versions of the same basic design were released, including the original Atari 400 and 800 and their successors, the XL and XE series of computers. Overall, the Atari 8-bit computer line was a commercial success, selling two million units through its major production run between late 1979 and mid-1985, a total of around 4 million units.
Origins
Design of the 8-bit series of machines started at Atari Inc.Atari, Inc
Atari, Inc. was an American video game and home computer company founded in 1972 by Nolan Bushnell and Ted Dabney. Primarily responsible for the formation of the video arcade and modern video game industries, the company was closed and its assets split in 1984 as a direct result of the North...
as soon as the Atari 2600
Atari 2600
The Atari 2600 is a video game console released in October 1977 by Atari, Inc. It is credited with popularizing the use of microprocessor-based hardware and cartridges containing game code, instead of having non-microprocessor dedicated hardware with all games built in...
games console was released in late 1977. The engineering team from Atari Grass Valley Research Center (originally "Cyan Engineering") felt that the 2600 would have about a three year lifespan before becoming obsolete. They started "blue sky" designs for a new console that would be ready to replace it around 1980, three years after the 2600's introduction. What they ended up with was essentially a "corrected" version of the 2600, fixing its more obvious flaws. The newer design would be faster than the 2600, have better graphics, and would include much better sound hardware. Work on the chips for the new system continued throughout 1978 and primarily focused on much-improved video hardware known as the Color Television Interface Adaptor, or CTIA.
During this gestation the home computer era began in earnest in the form of the TRS-80
TRS-80
TRS-80 was Tandy Corporation's desktop microcomputer model line, sold through Tandy's Radio Shack stores in the late 1970s and early 1980s. The first units, ordered unseen, were delivered in November 1977, and rolled out to the stores the third week of December. The line won popularity with...
, Commodore PET
Commodore PET
The Commodore PET was a home/personal computer produced from 1977 by Commodore International...
, and Apple II family—what Byte Magazine would later dub the "1977 Trinity". Ray Kassar, the then-new CEO of Atari from Warner Communications
Warner Communications
Warner Communications or Warner Communications, Inc. was established in 1971 when Kinney National Company spun off its non-entertainment assets, due to a financial scandal over its parking operations and changed its name....
, 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 peripheral
Peripheral
A peripheral is a device attached to a host computer, but not part of it, and is more or less dependent on the host. It expands the host's capabilities, but does not form part of the core computer architecture....
s, and run the then-universal BASIC programming language.
The need for character graphics led to the introduction of the ANTIC
ANTIC
Alphanumeric Television Interface Controller is an early video system chip used in the Atari 8-bit family of microcomputers as well as the Atari 5200 in the 1980s. The chip was patented by Atari, Inc. in 1981...
, a co-processor that ran in concert with the CTIA to provide graphics. Like the earlier TIA of the 2600, the CTIA was designed to produce sprites
Sprite (computer graphics)
In computer graphics, a sprite is a two-dimensional image or animation that is integrated into a larger scene...
and nothing else. ANTIC was built to generate conventional bitmap graphics
Raster graphics
In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium...
and characters, providing a number of different modes with varying color support and resolution. ANTIC and CTIA worked in concert to produce the complete display.
The early machines: 400 and 800
Management identified two sweet spot
Sweet spot
Sweet spot may refer to:*Sweet spot *Sweet spot *Sweet spot...
s 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
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
, a second 8 KB cartridge slot, monitor output
Composite video
Composite video is the format of an analog television signal before it is combined with a sound signal and modulated onto an RF carrier. In contrast to component video it contains all required video information, including colors in a single line-level signal...
(including 2 more pins for separate luma and chroma) and a full keyboard, while Candy used a plastic "membrane keyboard
Membrane keyboard
A membrane keyboard is a computer keyboard whose "keys" are not separate, moving parts, as with the majority of other keyboards, but rather are pressure pads that have only outlines and symbols printed on a flat, flexible surface...
" and internal slots for memory (not user upgradeable).
At the time, the Federal Communications Commission
Federal Communications Commission
The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...
(FCC) mandated that signal leakage in the television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
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 machines were built around very strong cast aluminum shields forming a partial Faraday cage
Faraday cage
A Faraday cage or Faraday shield is an enclosure formed by conducting material or by a mesh of such material. Such an enclosure blocks out external static and non-static electric fields...
, with the various components screwed down onto this internal framework. This had the advantage of producing an extremely sturdy 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 world via their own connectors. Instead, Atari designed the Serial Input/Output (SIO) computer bus
Computer bus
In computer architecture, a bus is a subsystem that transfers data between components inside a computer, or between computers.Early computer buses were literally parallel electrical wires with multiple connections, but the term is now used for any physical arrangement that provides the same...
, a daisy-chainable system that allowed multiple devices to connect to the computer through a single shielded connector. What internal slots existed were reserved for ROM and RAM modules.
Atari had originally intended to port Microsoft BASIC
Microsoft BASIC
Microsoft BASIC was the foundation product of the Microsoft company. It first appeared in 1975 as Altair BASIC, which was the first BASIC, and the first high level programming language available for the MITS Altair 8800 hobbyist microcomputer....
to the machine, as had most other vendors, intending to supply it on an 8 KB
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
ROM cartridge. However the existing 6502 version from Microsoft was 12 KB, and all of Atari's attempts to pare it down to 8 KB failed. Eventually they farmed out the work to a local consulting firm, Shepardson Microsystems
Shepardson Microsystems
Shepardson Microsystems, Inc. was a small company producing operating systems and programming languages for the Atari 8-bit and Apple II computer families...
, who recommended writing their own version from scratch, which was eventually delivered as Atari BASIC
Atari BASIC
Atari BASIC is a BASIC interpreter for the Atari 8-bit family of 6502-based home computers. The interpreter originally shipped on an 8 KB cartridge; on later XL/XE model computers it was built in, with an option to disable it, and started when the machines were booted with no other cartridges...
.
The machines were announced in late 1978 as the 400 and 800, although they were not 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. As memory prices continued to fall Atari eventually supplied the 800 fully expanded to 48 KB, using up all the slots. Overheating problems with the memory modules eventually led Atari to remove the module's 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.
Liz
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. Soldering that RAM to the motherboard would be much less expensive than the connectors and separate cards needed in the 800. At the same time the 400 did not 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. This reduction in complexity was helped by improvements in chip making since the original machines were released, allowing a number of separate chips in the original systems to be condensed into one. Atari also ordered a custom version of the 6502, initially labeled "6502C" but eventually known as SALLY to differentiate it from a standard 6502C, which added a single pin that allowed four support chips to be removed. The SALLY was incorporated into late-production 400/800 machines, all subsequent XL/XE machines and Atari 5200/7800 game systems.
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. In order to support expansion for high-end systems, similar to the card slots used in the Apple II or S-100 machines, the 1000 series also supported the Parallel Bus Interface (PBI), a single expansion slot on the back of the machine. An external chassis could be plugged into the PBI, supporting card slots for further expansion.
1200XL
Released in late 1982, the 1200XL was 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 PBI 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.
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. The machine was discontinued in 1983. There was no PAL version of the 1200XL.
Newer XL machines
Price war
Price war is a term used in economic sector to indicate a state of intense competitive rivalry accompanied by a multi-lateral series of price reduction. One competitor will lower its price, then others will lower their prices to match. If one of them reduces their price again, a new round of...
when Jack Tramiel
Jack Tramiel
Jack Tramiel is an American businessman, best known for founding Commodore International - manufacturer of the Commodore PET, Commodore 64, Commodore 128, Commodore Amiga, and other Commodore models of home computers.-Biography:...
of Commodore International
Commodore International
Commodore is the commonly used name for Commodore Business Machines , the U.S.-based home computer manufacturer and electronics manufacturer headquartered in West Chester, Pennsylvania, which also housed Commodore's corporate parent company, Commodore International Limited...
was attempting to undercut his old enemy Texas Instruments
Texas Instruments
Texas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...
. 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 had never been a deliberate target of Tramiel's wrath, they, along with the rest of the market, were dragged into "his" price war
Price war
Price war is a term used in economic sector to indicate a state of intense competitive rivalry accompanied by a multi-lateral series of price reduction. One competitor will lower its price, then others will lower their prices to match. If one of them reduces their price again, a new round of...
in order to maintain market share
Market share
Market share is the percentage of a market accounted for by a specific entity. In a survey of nearly 200 senior marketing managers, 67 percent responded that they found the "dollar market share" metric very useful, while 61% found "unit market share" very useful.Marketers need to be able to...
. The timing was particularly bad for Atari; 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 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. But by this point, in early 1983, the price war rapidly drove prices downward. Atari, attempting to beat this downward pressure, took the opportunity to move production of the new machines to the far east, where they could be produced for even lower costs.
Several versions of the new design, the 600XL, 800XL, 1400XL and 1450XLD were announced at the 1983 Summer CES
Consumer Electronics Show
The International Consumer Electronics Show is a major technology-related trade show held each January in the Las Vegas Convention Center, Las Vegas, Nevada, United States. Not open to the public, the Consumer Electronics Association-sponsored show typically hosts previews of products and new...
. The machines had Atari BASIC built into the ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
of the computer and the 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
Modem
A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...
and a voice synthesizer, and the 1450XLD also included a built-in double-sided
Double-sided disk
In computer science, a double-sided disk is a disk of which both sides are used to store data.Early floppy disks only used one surface for recording. The term "single sided disk" was not common until the introduction of double-sided disks, which offered double the capacity in the same physical size...
floppy disk
Floppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
drive in an enlarged case.
However, the production move ran into unexpected delays. Originally intended to replace the 1200XL in mid-83, the machines did not arrive until late in 1983. Although the 600/800 were well positioned in terms of price and features, during the critical Christmas season they were available only in small numbers while the Commodore 64
Commodore 64
The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...
was widely available. Although the 800XL would be the most popular computer sold by Atari, it was unable to defend Atari's marketshare, and the race to the bottom
Race to the bottom
A race to the bottom is a socio-economic concept that is argued to occur between countries as an outcome of regulatory competition, progressive taxation policies and social welfare spending...
gutted their profits. Combined with the simultaneous effects of the video game crash of 1983
Video game crash of 1983
The North American video game crash was a serious event that brought an abrupt end to what is considered the second generation of console video gaming in North America. Beginning in 1983, the crash almost destroyed the then-fledgling industry and led to the bankruptcy of several companies producing...
, Atari was soon losing millions of dollars a day. Their owners, Warner Communications
Warner Communications
Warner Communications or Warner Communications, Inc. was established in 1971 when Kinney National Company spun off its non-entertainment assets, due to a financial scandal over its parking operations and changed its name....
, became desperate to sell off the division.
Through this process 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
Atari 7800
The Atari 7800 ProSystem, or simply the Atari 7800, is a video game console re-released by Atari Corporation in January 1986. The original release had occurred two years earlier under Atari Inc. The 7800 had originally been designed to replace Atari Inc.'s Atari 5200 in 1984, but was temporarily...
. In the end the 1400XL was eventually canceled outright, and the 1450XLD so delayed that it would never ship. Other 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, while the 1650XLD was a similar machine in the 1450XLD case. These were canceled when James J. Morgan
James J. Morgan
James J. Morgan is a former American executive who served as CEO of Atari from 1983 to 1984 and CEO of Philip Morris USA from 1994 to 1997.James Morgan first joined Philip Morris in 1963...
became CEO and wanted Atari to return to its video game roots. The 1850XLD was to have been based on the Amiga Lorraine
Amiga
The Amiga is a family of personal computers that was sold by Commodore in the 1980s and 1990s. The first model was launched in 1985 as a high-end home computer and became popular for its graphical, audio and multi-tasking abilities...
(later to become the Commodore Amiga
Amiga
The Amiga is a family of personal computers that was sold by Commodore in the 1980s and 1990s. The first model was launched in 1985 as a high-end home computer and became popular for its graphical, audio and multi-tasking abilities...
). These models were canceled when Jack Tramiel took over Atari and changed the XL series development into the XE series. The new Atari scrapped plans for the Amiga-based 1850XLD system for the Atari ST
Atari ST
The Atari ST is a home/personal computer that was released by Atari Corporation in 1985 and commercially available from that summer into the early 1990s. The "ST" officially stands for "Sixteen/Thirty-two", which referred to the Motorola 68000's 16-bit external bus and 32-bit internals...
system.
Although Commodore emerged intact from the computer price wars, fighting inside Commodore soon led to Jack Tramiel
Jack Tramiel
Jack Tramiel is an American businessman, best known for founding Commodore International - manufacturer of the Commodore PET, Commodore 64, Commodore 128, Commodore Amiga, and other Commodore models of home computers.-Biography:...
's ousting. Looking to re-enter the market, he soon purchased Atari consumer division from Warner for an extremely low price.
Tramiel era: XE series and XE Game System
Jack Tramiel's Atari CorporationAtari Corporation
Atari Corporation was a manufacturer of computers and video game consoles from 1984 to 1996. Atari Corp. was founded in July of 1984 when Warner Communications sold the home computing and game console divisions of Atari to Jack Tramiel. Its chief products were the Atari ST, Atari XE, Atari 7800,...
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
Atari ST
The Atari ST is a home/personal computer that was released by Atari Corporation in 1985 and commercially available from that summer into the early 1990s. The "ST" officially stands for "Sixteen/Thirty-two", which referred to the Motorola 68000's 16-bit external bus and 32-bit internals...
series, and visually 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), which was electronically almost compatible with the Parallel Bus Interface (PBI), but physically smaller, since it was located next to the standard 400/800-compatible Cartridge Interface and provided only those signals that did not exist in the latter; ECI peripherals were expected to plug into both the standard Cartridge Interface and the ECI port. The 130XE shipped with 128 KB of memory, accessible through bank-selection.
An additional 800XE was available in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
(mostly Eastern Europe
Eastern Europe
Eastern Europe is the eastern part of Europe. The term has widely disparate geopolitical, geographical, cultural and socioeconomic readings, which makes it highly context-dependent and even volatile, and there are "almost as many definitions of Eastern Europe as there are scholars of the region"...
), 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
Nintendo
is a multinational corporation located in Kyoto, Japan. Founded on September 23, 1889 by Fusajiro Yamauchi, it produced handmade hanafuda cards. By 1963, the company had tried several small niche businesses, such as a cab company and a love hotel....
, Atari Corp. brought out the XE Game System
Atari XEGS
The Atari XE Video Game System is a video game console released by Atari Corporation in 1987. Based on the Atari 65XE computer, the XEGS is compatible with the existing Atari 8-bit computer software library. Additionally, it is able to operate as a stand alone console or full computer with the...
(XEGS), released in 1987. The XE Game System was sold bundled with a detachable keyboard, a joystick and a light gun (XG-1
XG-1
The XG-1 is the light gun that came bundled with the Atari XEGS that was released in 1987. The XEGS, which stands for "XE Game System", was an Atari 65XE computer reworked cosmetically to give the appearance of a game console. The light gun was bundled to compete with the Nintendo Entertainment...
), 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.
On January 1, 1992, Atari corp. officially dropped all remaining support of the 8-bit line.
Design
The Atari machines consist of a 6502 as the main processor, a combination of ANTIC and GTIA chips to provide graphics, and the POKEY chip to handle sound and serial input/output. These "support" chips are controlled via a series of registerHardware register
In digital electronics, especially computing, a hardware register stores bits of information, in a way that all the bits can be written to or read out simultaneously.The hardware registers inside a central processing unit are called processor registers....
s that can be user-controlled via memory set/get instructions running on the 6502. For example, the GTIA uses a series of registers to select colors for the screen; these colors can be changed by inserting the correct values into its registers, which are mapped into "memory"
Memory-mapped I/O
Memory-mapped I/O and port I/O are two complementary methods of performing input/output between the CPU and peripheral devices in a computer...
that is visible to the 6502. Some parts of the system also use some of the machine's RAM as a buffer, notably the ANTIC's display buffer and its Display List (essentially a small program written in the chip's simple machine language that tells ANTIC how to interpret that data and turn it into a display), as well as GTIA's sprite information. These features enable the computer to perform many functions directly in hardware, such as smooth background scrolling, that would need to be done in software in most other computers of the time.
ANTIC
ANTICANTIC
Alphanumeric Television Interface Controller is an early video system chip used in the Atari 8-bit family of microcomputers as well as the Atari 5200 in the 1980s. The chip was patented by Atari, Inc. in 1981...
is a microprocessor which processes display instructions. A complete sequence of instructions is known as a Display List. Each instruction describes how a single "line" on the screen is to be displayed (specifying one of several character or graphics modes available), where it is displayed, if it contains interrupts, if fine scrolling is enabled or not, and optionally where to load data from memory (text or graphics information). Since each line can be programmed individually, this feature enables the programmer to create displays made up of mixed graphics and text, as well as different graphics modes on the screen at once. It also enables the machine to quickly "scroll" the screen vertically or horizontally by means of a single memory write. ANTIC reads this Display List and the display data using DMA (Direct Memory Access), then translates the result into electrical data for GTIA to process. This process is performed without any CPU intervention.
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 draws 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.
CTIA/GTIA
The Color Television Interface Adaptor (CTIA) is the graphics chip used in early Atari 400/800 home computers. It is the successor to the TIA chip used in the Atari 2600. According to Joe Decuir, George McLeod designed the CTIA in 1977. The CTIA chip was replaced with the Graphic Television Interface Adaptor (GTIA) in later revisions of the 400 and 800 and all other members of the Atari 8-bit family. GTIA, also designed by George McLeod, adds three new graphics modes that enables the display of more colors on the screen than previously available.The CTIA/GTIA receives graphics information from ANTIC and also controls sprites
Sprite (computer graphics)
In computer graphics, a sprite is a two-dimensional image or animation that is integrated into a larger scene...
(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.
POKEY
The third custom support chip, named POKEYAtari POKEY
The Pot Keyboard Integrated Circuit is a digital I/O chip found in the Atari 8-bit family of home computers and many arcade games in the 1980s. It was commonly used to sample potentiometers and scan matrices of switches...
, is responsible for reading the keyboard, generating sound and serial communications (in conjunction with the PIA). It also provides timers, a random number generator (for generating acoustic noise
Noise
In common use, the word noise means any unwanted sound. In both analog and digital electronics, noise is random unwanted perturbation to a wanted signal; it is called noise as a generalisation of the acoustic noise heard when listening to a weak radio transmission with significant electrical noise...
as well as random numbers), and maskable interrupts. POKEY has four semi-independent audio channels, each with its own frequency, noise and volume control. Each 8-bit channel has its own audio control register which select the noise content and volume. For higher sound resolution (quality), two of the audio channels can be combined for more accurate sound (16-bit). The name POKEY comes from the words "POtentiometer" and "KEYboard", which are two of the I/O devices that POKEY interfaces with (the potentiometer is the mechanism used by the paddle
Paddle (game controller)
A paddle is a game controller with a round wheel and one or more fire buttons, where the wheel is typically used to control movement of the player object along one axis of the video screen...
). This chip is actually used in several Atari arcade machines of the 80s, including Missile Command
Missile Command
Missile Command is a 1980 arcade game by Atari, Inc. that was also licensed to Sega for European release. It is considered one of the most notable games from the Golden Age of Video Arcade Games...
and Asteroids Deluxe, among others.
Computer models
- 400 and 800 (1979) – original machines in beige cases, 400 has a membrane keyboardMembrane keyboardA membrane keyboard is a computer keyboard whose "keys" are not separate, moving parts, as with the majority of other keyboards, but rather are pressure pads that have only outlines and symbols printed on a flat, flexible surface...
, 800 has full-travel keys, two cartridge ports, monitor output. Both machines have expandable memory slots (up to 48 KB). Later PAL versions have the 6502C processor. - 1200XL (1982) – new aluminum and smoked plastic cases, 64 KB of RAM, only two joystick ports. Help key, four function keys. Older software, if it was written improperly, caused compatibility problems with the new OS.
- 600XL and 800XL (1983) – replacements for the 400, 800 and 1200XL sans function keys. 600XL have 16 KB of memory, PAL versions had a monitor port, 800XL have 64 KB and monitor output. Both have built-in BASIC and an expansion port known as the Parallel Bus Interface (PBI)Parallel Bus Interface (PBI)The Parallel Bus Interface, or PBI, is a 50-pin port found on some Atari 8-bit XL computers. It provides unbuffered, direct connection to the system bus lines , running at the same speed as the 6502 CPU. The 600XL and 800XL computers, along with the unreleased 1400XL and 1450XLD had a PBI interface...
. - 800XLF – 800XL with Atari FREDDIE chip and BASIC rev. C. Released in Europe only.
- 65XE and 130XE (1985) – A repackaged 800XLF with new cases and keyboards. The 130XE has 128 KB of RAM and a Enhanced Cartridge Interface (ECI)Enhanced Cartridge Interface (ECI)The Enhanced Cartridge Interface or ECI was a 14-pin extension to the cartridge slot on Atari 8-bit XE computers. This allowed external devices access to the system's data and bus lines...
instead of a PBI. The U.S./Canadian version of the 65XE has no ECI or PBI. - XE Game System (1987) – a game machine in a light beige case, with a detachable full-travel but slightly "mushy" keyboard (Atari ST'ish)
- 800XE – the final machine in the series. Styling the same as 65XE and 130XE. A 130XE with 64 KB RAM. Mainly seen in Eastern Europe.
- Prototypes/Vaporware (Never Officially Released)
- 1400XL – Similar to the 1200XL but with a PBI, FREDDIEAtari FREDDIEFREDDIE was the name for a 40-pin LSI found in Atari 8-bit computers. It is a RAM address multiplexer, used for DRAM access. Atari created this chip to replace several other chips to cut costs and to enhance CPU and ANTIC memory access....
chip, built-in modem and speech synthesis chip. Cancelled by Atari. - 1450XLD – basically a 1400XL with built in 5¼″ disk drive and expansion bay for a second 5¼″ disk drive. Code named Dynasty. Made it to pre-production, but got abandoned by Tramiel.
- 1600XL – codenamed Shakti, this was dual-processor system with 6502 and 80186 processors and two built-in 5¼″ floppy disk drives.http://www.atarimuseum.com/computers/8BITS/XL/1600xl/1600xl.html
- 900XLF – redesigned 800XLF. Became the 65XE.
- 65XEM – 65XE with AMY sound synthesis chip. Cancelled.
- 65XEP – "portable" 65XE with 3.5" disk drive, 5" green CRTCathode ray tubeThe cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...
and battery pack. Never released - 1090XL expansion system, 5 slots in a large case (never released, small numbers leaked out)
- 1055 3½" floppy drive http://www.backntime.net/Atari%20Computers/8bit/Prototype/Frame8bitProto.html
- XF351 3½" floppy drive http://www.backntime.net/Atari%20Computers/8bit/Prototype/Frame8bitProto.html
- XF354 3½" floppy drive
- 1400XL – Similar to the 1200XL but with a PBI, FREDDIE
Peripherals
- Several dedicated cassette tape drives. All were similar, and capable of recording at 600 bit/s on a standard audio cassetteCompact CassetteThe Compact Cassette, often referred to as audio cassette, cassette tape, cassette, or simply tape, is a magnetic tape sound recording format. It was designed originally for dictation, but improvements in fidelity led the Compact Cassette to supplant the Stereo 8-track cartridge and reel-to-reel...
. (Unlike some computer systems, it was not possible to use a standard cassette deck with the Atari for this purpose.) - Various 5.25-inch floppy disk drives, including single, enhanced and true double-density models.
- Several printerComputer printerIn computing, a printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a...
s of various types; dot matrix, thermal, 4-color plotter and letter-quality daisy wheel. - Modems, including one model with an acoustic coupler and other direct-connect models.
- Other peripherals, including a CentronicsCentronicsCentronics Data Computer Corporation was a pioneering American manufacturer of computer printers, now remembered primarily for the parallel interface that bears its name.-The beginning:Centronics began as a division of Wang Laboratories...
/RS-232RS-232In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...
expansion system, numeric keypad, memory module, touch tablet and an 80-column display module.
Atari's peripherals used the proprietary SIO port, which allowed them to be daisy chain
Daisy chain
Daisy chain may refer to a daisy garland created from daisy flowers, the original meaning and the one from which the following derive by analogy:*Daisy chain *Daisy chain *Daisy chain...
ed together into a single string. These "intelligent" peripherals were more expensive than the standard IBM PC devices, which did not need the added SIO electronics.
Built-in
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
. The Atari 400/800 had the following:
- OS Rev. A - 10 KB ROM (3 chips) early machines.
- OS Rev. B - 10 KB ROM (3 chips) bug fixes. Most common for 400/800.
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.
- OS Rev. 10 - 16 KB ROM (2 chips) for 1200XL Rev A
- OS Rev. 11 - 16 KB ROM (2 chips) for 1200XL Rev B (bug fixes)
- OS Rev. 1 - 16 KB ROM for 600XL
- OS Rev. 2 - 16 KB ROM for 800XL
- OS Rev. 3 - 16 KB ROM for 800XE/130XE
- OS Rev. 4 - 32 KB ROM (16 KB OS + 8 KB BASIC + 8 KB Missile Command) for XEGS
The XL/XE models also came with the Atari BASIC
Atari BASIC
Atari BASIC is a BASIC interpreter for the Atari 8-bit family of 6502-based home computers. The interpreter originally shipped on an 8 KB cartridge; on later XL/XE model computers it was built in, with an option to disable it, and started when the machines were booted with no other cartridges...
ROM built in, which could be disabled at startup by holding down the silver OPTION key to the right of the keyboard. Early models came with the notoriously buggy revision B. Later models used revision C.
Disk Operating System
The standard Atari OS only contained very low-level routines for accessing floppy diskFloppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
drives. An extra layer, a disk operating system
Disk operating system
Disk Operating System and disk operating system , most often abbreviated as DOS, refers to an operating system software used in most computers that provides the abstraction and management of secondary storage devices and the information on them...
, was required to assist in organizing file system
File system
A file system is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device which contain it. A file system organizes data in an efficient manner and is tuned to the...
-level disk access. This was known as Atari DOS
Atari DOS
Atari DOS is the disk operating system used with the Atari 8-bit family of computers. Operating system extensions loaded into memory were required in order for an Atari computer to access a disk drive. These extensions to the operating system added the disk handler and other file management...
, 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.
- DOS 1.0 - Initial DOS for Atari.
- DOS 2.0S, 2.0D - Improved over DOS 1.0, became the standard for the 810 disk drive. 2.0D was for the never-released 815 drive.
- DOS 3.0 - Came with 1050 drive. Used a different disk format from previous DOSes, and was incompatible with DOS 2.0, making it very unpopular.
- DOS 2.5 - Replaced DOS 3.0 with later 1050s. Functionally identical to DOS 2.0S, but able to read and write enhanced Density disks.
- DOS 4.0 - Designed for 1450XLD, cancelled, rights given back to the author.
- DOS XE - Designed for the XF551 drive.
Several third-party replacement DOSes were also available, sometimes quite advanced, such as SpartaDOS X
SpartaDOS X
SpartaDOS X is a disk operating system for the Atari 8-bit family of computers that closely resembles MS-DOS. It was developed and sold by ICD, Inc. in 1987-93.- History :...
.
Other software
Amongst the many pieces of software released for the 8-bit Atari computers, a large number of programming languages were implemented, including:-- AssemblersAssembly languageAn assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...
, via the Atari Assembler EditorAtari Assembler EditorThe Atari Assembler Editor cartridge was a program used to edit, compile and debug assembly language programs for the Atari 8-bit computers. It was programmed by Kathleen O'Brien of Shepardson Microsystems, Inc.- Details :...
, Atari Macro Assembler, MAC/65MAC/65MAC/65 was an assembler produced by Optimized Systems Software for the Atari 8-bit family of microcomputers. It was a direct descendent of OSS's EASMD. Much like the Atari Assembler Editor cartridge, MAC/65 combined a line editor, assembler, and debugger into a single package. MAC/65 was notable...
, and several others. - BASICBASICBASIC is a family of general-purpose, high-level programming languages whose design philosophy emphasizes ease of use - the name is an acronym from Beginner's All-purpose Symbolic Instruction Code....
; Atari BASICAtari BASICAtari BASIC is a BASIC interpreter for the Atari 8-bit family of 6502-based home computers. The interpreter originally shipped on an 8 KB cartridge; on later XL/XE model computers it was built in, with an option to disable it, and started when the machines were booted with no other cartridges...
was the "standard" BASIC implementation for the 8-bit family, originally a ROM cartridge, and built-in from the 600XL/800XL onwards. Other BASICs included Atari Microsoft BASICAtari Microsoft BASICThe Atari Microsoft BASIC and Atari Microsoft BASIC II variants of the BASIC programming language were cartridge or floppy disk packaged versions of the Microsoft BASIC dialect ported to the Atari 8-bit machines....
, Turbo Basic XL, BASIC XL and Advan BASIC. - C (Programming Language)C (programming language)C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
, via the Deep Blue CDeep Blue CThe Deep Blue C is one of the few C compilers for the Atari 8 bit. John H. Palevich is the author of this compiler. The syntax supported by DBC is close to the ANSI C with significant limitations.- Limitations :...
, Lightspeed C and cc65Cc65-External links:***...
compiler. - Other languages including LOGO (Atari LOGOAtari LOGOAtari LOGO was a programming language for the Atari 8-bit computers.Atari LOGO was developed by Logo Computer Systems, Inc. in Quebec, Canada. Since LCSI wrote Apple Logo, the Atari version maintained strong compatibility with it. Atari LOGO also featured commands that supported the Atari 8-bit...
), LISPLispA lisp is a speech impediment, historically also known as sigmatism. Stereotypically, people with a lisp are unable to pronounce sibilants , and replace them with interdentals , though there are actually several kinds of lisp...
(INTER-LISP/65), PILOTPILOTProgrammed Instruction, Learning, Or Teaching is a simle historic programming language developed in the 1960s.Like its younger sibling LOGO programming language, it was an early foray into the technology of computer assisted instruction ....
(Atari PILOT), several versions each of Forth and Pascal, Action!Action programming languageAction! is a programming language, with integrated editor, debugger, and 6502 compiler, for the Atari 8-bit family of microcomputers. Action! was created by Clinton Parker and released on cartridge by Optimized Systems Software in 1983...
(a high performance Atari-specific language from OSS), and WSFNWSFN (programming language)WSFN was a programming language for controlling robots created by Li-Chen Wang and published by Dr. Dobb's Journal in September 1977...
(which stands for nothing).
More recently, cross platform development tools (most commonly run on PC
IBM PC compatible
IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. Such computers used to be referred to as PC clones, or IBM clones since they almost exactly duplicated all the significant features of the PC architecture, facilitated by various manufacturers' ability to...
s), have become popular for retrocomputing
Retrocomputing
Retrocomputing is the use of early computer hardware and software today. Retrocomputing is usually classed as a hobby and recreation rather than a practical application of technology; enthusiasts often collect rare and valuable hardware and software for sentimental reasons...
software development.
Graphics capabilities
- 40×24 text modes
- 1 color of text, with each character's 8×8 pixels the same size as those in 320×192 graphics mode, with the same hue restriction. Characters with the high-bit on were represented in inverse-video.
- "Lowercase with descenders" mode, which was not available through GRAPHICS, only as part of custom display lists. In this mode characters were 10 pixels high and occupied either the upper or lower 8 pixels of that height. This was not strictly speaking a 40×24 text mode, because of the unusual height.
- Colored text, where every two bits represents a colored pixel (characters were 4×8 pixels that were the same size as those in 160×192 graphics mode). Characters with the high-bit on were displayed using a 5th color palette register where the 4th would normally be used.
- Colored text, where every four bits represents a colored pixel (characters were 2×8 pixels that were the same size as those in 80×192 graphics mode and had the same color limitations). This mode was not directly available through GRAPHICS but required setting GTIA flags in text mode.
- 20×24 text mode
- 1 color of text, with each character's 8×8 pixels the same size as those in 160×192 graphics mode. Characters with various bits enabled or disabled (which would normally appear as 'control-characters', lower-case characters, or inverse-video) were displayed with different colored pixels.
- 20×12 text mode
- (Same as 20×24 text mode, but with larger pixels and fewer rows of text)
- 40×24 graphics mode — 4 colors (2 bpp)
- 80×48 graphics modes — Either 2 colors (1 bpp), or 4 colors (2 bpp)
- 160×96 graphics modes — Either 2 colors, or 4 colors
- 160×192 graphics modes — Either 2 colors, or 4 colors
- 320×192 graphics mode — 2 colors (1 bpp). The pixels were a shade of the playfield color, and could not be different hue. (In practice on NTSC models, this actually resulted in 4 possible colors on a standard TV screen: black, white, blue, and brown, the last two colors being caused by using pixels in only even or only odd columns — thus the blue and brown regions were effectively in 160×192 resolution).
- 80×192 graphics modes (GTIA chip only)
- 9 colors from the color palette registers
- All 15 Atari hues, but only of one brightness (plus black)
- All 16 Atari shades, but only of one hue
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 be 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.
Software-driven modes
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 80×192 modes and 80×24 character displays. One difficulty with these modes was that the gratingGrating
A grating is any regularly spaced collection of essentially identical, parallel, elongated elements. Gratings usually consist of a single set of elongated elements, but can consist of two sets, in which case the second set is usually perpendicular to the first...
on PAL and NTSC televisions is very different, as is the update speed and resolution, and so often they would display well on European systems and awfully on US ones, or vice versa. For the same reason they may not display well – or display rather too well – on simulators.
It was also possible by using the display list to display far more than the usual number of sprites on the screen, with more colours than available. This is done by beginning and ending instructions referencing the 'player missile graphics' on separate display list lines. Modifying these values allowed the programmer to move the sprites around and change their colours 'on the fly'. The same technique could be employed to display far more colours than seemingly allowed in any particular graphics mode, which could be mixed and altered at will.
Because the screen memory could be accessed by two pointers and relocated anywhere in available memory, it was also extremely easy to implement hardware scrolling and page flipping to enable easy game design and programming.
There are many examples of demo programs available on the internet, displaying these and other features which outperform other 8 bit machines of the time.
See also
- History of Atari
- A.N.A.L.O.G.A.N.A.L.O.G.A.N.A.L.O.G. was an American computer magazine devoted to the Atari 8-bit home computer line. It was known for its "advanced" programs in comparison to most type-in magazines of the era, especially its main rival, ANTIC, another long-lived magazine devoted to the Atari 8-bit line...
magazine - ANTICANTIC (magazine)Antic was the name of a home computer magazine devoted to the Atari 8-bit computer line . Its ISSN is 0113-1141. It took its name from the ANTIC chip, which produced the Atari line's graphics. The first issue was published in April 1982. While it began as a bimonthly magazine, within a year it had...
magazine - Atari UserAtari UserAtari User was a British computer magazine aimed at users of Atari home computers, and published by Database Publications between 1985 and 1988....
magazine - Page 6Page 6Page 6 was an independent British publication aimed at users of Atari home computers. It was published between 1982 and 1998...
magazine
General
- The Atari History Museum
- Atari 8-Bit Computers: Frequently Asked Questions
- The Atari 8-bit Computer WebRing
- Stan Veit's Atari 800 History
- ATARI 65 XE with arabic keyboard
- Gamasutra's "A History of Gaming Platforms: Atari 8-bit Computers" by Bill Loguidice and Matt Barton
- Gamasutra's "The History of Atari" Part 1:1971-77 | Part 2:1978-81, by Steve Fulton
Technical information
Software, games, music, demos
- Atari SAP Music Archive
- Atari Archives
- XL Search – A searchable index of files from numerous Atari FTP archives and websites
- Reminiscing: 8-Bit Atari Games
- Database of Atari games, demos and software