Atari 400 (1979)

An Atari 800XL, one of the most popular machines in the series.

The Atari 8-bit family is a series of 8-bit home computers manufactured by Atari Inc. starting in 1979, and later Atari Corporation starting in 1984. Eight-bit CPUs normally use an 8-bit data bus and a 16-bit address bus which means that their Address space is limited to 64 KBs This is not a "natural A home computer was a class of Personal computer entering the market in 1977 and becoming common during the 1980s Atari Inc was a video game and computer company founded in 1972 by Nolan Bushnell and Ted Dabney Atari Corporation was a manufacturer of computers and video game consoles from 1984 to 1996 Year 1984 ( MCMLXXXIV) was a Leap year starting on Sunday (link displays the 1984 Gregorian calendar) All are based on the MOS Technology 6502 CPU and were the first home computers designed with custom coprocessor chips, giving them "the most powerful graphic subsystem" of any 8 bit machine[1]. MOS Technology Inc, also known as CSG (Commodore Semiconductor Group, was a semiconductor design and fabrication company based in Norristown Pennsylvania The MOS Technology 6502 is an 8-bit Microprocessor that was designed by Chuck Peddle for MOS Technology in 1975 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.

History

Origins

Design of the 8-bit series of machines started as soon as the Atari 2600 games console was released in late 1977. The Atari 2600 is a Video game console released in October 1977 The engineering team from Atari Inc. 's Grass Valley Research Center (who called themselves Cyan Engineering) felt that the 2600 would have about a three year lifespan before becoming obsolete, and started "blue skying" designs for a new console that would be ready to replace it around 1980. What they ended up with was essentially a "corrected" version of the 2600, fixing its more obvious flaws. ^[1] 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 Adapter, or CTIA.

During this gestation the home computer era began in earnest in the form of the Apple II family, Commodore PET and TRS-80. The PET ( P ersonal E lectronic T ransactor) was a home -/ Personal computer produced by Commodore starting in 1977 TRS-80 was Tandy Corporation 's desktop Microcomputer model line sold through Tandy's Radio Shack stores in the late 1970s and early Ray Kassar, the then-new CEO of Atari Inc. from Warner Communications, wanted the new chips to be used in a home computer to challenge Apple. Time Warner Inc ( is the world's largest media and entertainment conglomerate, headquartered in New York City. 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. For an account of the words periphery and peripheral as they are used in biology sociology politics computer hardware and other fields see the In Computer programming, BASIC (an Acronym for Beginner's All-purpose Symbolic Instruction Code) is a family of High-level programming languages

Management identified two sweet spots for the new computers, a low-end version known as Candy, and a higher-end machine known as Colleen (rumored to be named after attractive Atari Inc. A sweet spot is a place often numerical as opposed to physical where a combination of factors suggest a particularly suitable solution staff). The primary difference between the two models was marketing; Atari Inc. 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 8k cartridge slot, monitor output and a full keyboard, while Candy used a plastic "membrane keyboard" and internal slots for memory (not user upgradable). Composite video is the format of an Analog television (picture only signal before it is combined with a sound signal and modulated onto an RF 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 Both machines were very sturdy with huge internal aluminum shields, originally to meet FCC rules for TV signals emitted in RF space.

Atari 800

Atari Inc. had originally intended to port Microsoft BASIC to the machine, as had most other vendors, intending to supply it on an 8 KB^[2] ROM cartridge. Microsoft BASIC was the foundation product of the Microsoft company A kilobyte (derived from the SI prefix Kilo -, meaning 1000 is a unit of Information or Computer storage equal to either 1024 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. For the version of BASIC bundled with the Atari ST computer series see Atari ST BASIC.

The early machines: 400 and 800

The machines were announced in December 1978 as the 400 and 800, although they weren't widely available until November 1979, much closer to the original design date. Year 1978 ( MCMLXXVIII) was a Common year starting on Sunday (link displays the 1978 Gregorian calendar) 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.

Due to the FCC restrictions, the 400/800 couldn't allow expansion slots like those found on the Apple II computers. Instead, they created a proprietary, expensive serial interface called Serial Input/Output (SIO). All external devices were connected using this interface in a daisy-chain fashion. On the 800, the internal slots were reserved for ROM and memory modules.

Originally the 800 shipped with 8 KB, but as memory prices continued to fall Atari Inc. 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.

Liz

The hardware self-test screen of later Atari 8-bit models (XL series onwards).

The 400 and 800 were complex and expensive machines to build, consisting of multiple circuit boards mostly enclosed by massive cast iron and 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 a real 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 Inc. Year 1982 ( MCMLXXXII) was a Common year starting on Friday (link displays the 1982 Gregorian calendar) started the Sweet 8 (or "Liz NY") and Sweet 16 projects to address these issues. 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. Improvements in chip making allowed a number of chips in the original systems to be condensed into one. In the Microelectronics industry a semiconductor fabrication plant (commonly called a fab) is a factory where devices such as Integrated circuits are manufactured For comparison, the original 800 used seven separate circuit boards while the new machines used only one. Atari Inc. 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.

1200XL

Atari 1200XL

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. ^[3] Released in late 1982, the machine was discontinued in 1983.

Newer XL machines

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. Price war is a term used in Business to indicate a state of intense competitive rivalry accompanied by a multi-lateral series of price reductions Jack Tramiel (born 13 December 1928) is a Businessman, best known for founding Commodore International - manufacturer of the Commodore Commodore, the commonly used name for Commodore International, was a US-American Electronics company based in West Chester Pennsylvania Texas Instruments ( better known in the electronics industry (and popularly as TI, is an American company based in Dallas, Texas, USA 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. Market share, in Strategic management and Marketing, is the percentage or proportion of the total available Market or Market segment that is

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.

Atari 600XL

Atari 800XL

Several versions of the new design, the 600XL, 800XL, 1400XL and 1450XLD were announced at the 1983 Summer CES. The International Consumer Electronics Show (CES is a Trade show held each January in Las Vegas, Nevada, and is sponsored 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 Parallel Bus Interface or PBI is a 50-pin port found on some Atari 8-bit XL computers 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. Modem (from mo dulator- dem odulator is a device that modulates an analog carrier signal to encode Digital information Speech synthesis is the artificial production of human speech. A floppy disk is an increasingly Obsolete data storage medium that is composed of a disk of thin flexible ("floppy" Magnetic storage medium encased

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. The Atari 7800 ProSystem, or simply the Atari 7800, is a Video game console released by Atari Corporation in June 1986 In the end the 1400XL was eventually canceled outright, and the 1450XLD so delayed that it would never ship.

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. The North American video game crash of 1983 (sometimes known as the video game crash of 1984 because it was in that year that the full effects of the crash became apparent was soon losing millions of dollars a day. Their owners, Warner Communications, became desperate to sell off the division. Time Warner Inc ( is the world's largest media and entertainment conglomerate, headquartered in New York City.

Although Commodore emerged intact from the computer price wars, fighting inside Commodore soon led to Jack Tramiel's ousting. Jack Tramiel (born 13 December 1928) is a Businessman, best known for founding Commodore International - manufacturer of the Commodore Looking to re-enter the market, he soon purchased Atari Inc. 's consumer division from Warner for an extremely low price.

Tramiel era: XE series and XEGS

Atari 130XE

Atari 65XE

Jack Tramiel's Atari Corp. 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. The Atari ST is a home / Personal computer that was commercially available from 1985 to the early 1990s 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. Eastern Europe is a general term that refers to the Geopolitical region encompassing the easternmost part of the European continent. Unfortunately, the 65XE and 800XE machines sold in Eastern Europe had a buggy GTIA chip, specifically those machines made in China in 1991.

Atari XE Game System

Finally, with the resurgence of the gaming industry brought on by Nintendo, Atari Corp. is a Multinational corporation headquartered in Kyoto Japan founded on brought out the XE Game System (XEGS), released in 1987. The XEGS 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 XG-1 is the Light gun that came bundled with the Atari XEGS. The XEGS 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. New Year See also New Year The Ancient Romans began their consular year on January 1st since 153 BC Year 1992 ( MCMXCII) was a Leap year starting on Wednesday (link will display full 1992 Gregorian calendar) officially dropped all remaining support of the 8-bit line.

Design

The Atari machines consisted 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 were controlled via a series of registers that could be user-controlled via memory set/get instructions running on the 6502. 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 For example, the GTIA used a series of registers to select colors for the screen; these colors could be changed by inserting the correct values into its registers, which were mapped into "memory" that was visible to the 6502. Some parts of the system also used 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 told ANTIC how to interpret that data and turn it into a display), as well as GTIA's sprite information. Machine code or machine language is a system of instructions and data executed directly by a Computer 's Central processing unit.

ANTIC

ANTIC was a microprocessor which processed display instructions. This article refers to the display chip For the football manager see Radomir Antić. A complete sequence of instructions was known as a Display List. Each instruction described how a single "line" on the screen was to be displayed (specifying one of several character or graphics modes available), where it was displayed, if it contained interrupts, if fine scrolling was enabled or not, and optionally where to load data from memory (text or graphics information). Since each line could be programmed individually, this feature enabled the programmer to create displays comprised of mixed graphics and text, as well as different graphics modes on the screen at once. It also enabled the machine to quickly "scroll" the screen vertically or horizontally by means of a single memory write. ANTIC read this Display List and the display data using DMA (Direct Memory Access), then translated the result into electrical data for GTIA to process. This process was performed without any CPU intervention.

The ANTIC was primarily responsible for drawing the "background" of the graphics screen, as well as text. ANTIC then passed off the video data through the GTIA, which added color and drew sprites (which Atari called "players" and "missiles"). The combination led to oddities such as the ability to invert all the text on the screen by changing a value in memory. The character set was easily redirected by changing an ANTIC register, allowing the user to create their own character sets with relative ease. A character encoding consists of a code that pairs a sequence of characters from a given character set (sometimes incorrectly referred to as Code page

CTIA/GTIA

The Color Television Interface Adapter was the graphics chip used in early Atari 400/800 home computers; it was the successor to the TIA chip used in the Atari 2600. The Atari 8-bit family of computers use a series of custom Television Interface Adapter (TIA chips called CTIA and GTIA respectively The Television Interface Adapter ( TIA) is the custom chip that is the heart of the Atari 2600 game console and was created by Jay Miner of Amiga The CTIA chip was replaced with the GTIA in later revisions of the 400 and 800 and all other members of the Atari 8-bit family. According to Joe Decuir, George McLeod designed the CTIA (Colleen TIA) in 1977.

The CTIA/GTIA received graphics information from ANTIC and also controlled 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). In Computer graphics, a sprite (also known by other names see Synonyms below is a two-dimensional/three-dimensional Image or Animation that CTIA/GTIA output them as separate digital luminance and chrominance signals, which were mixed to form an analogue composite video signal.

GTIA, also designed by George McLeod, added three new graphics modes that enabled the display of more colors on the screen than previously available. The Atari 8-bit family of computers use a series of custom Television Interface Adapter (TIA chips called CTIA and GTIA respectively These modes were, however, rarely used due to their extremely low resolution (80x192).

POKEY

The third custom support chip, named POKEY, was responsible for reading the keyboard, generating sound and serial communications (in conjunction with the PIA). It also provided timers, a random number generator (for generating acoustic noise as well as random numbers), and maskable interrupts. A random number generator (often abbreviated as RNG is a computational or physical device designed to generate a sequence of Numbers or symbols that lack any is a one volume manga created by Tsutomu Nihei as a prequel to his ten-volume work Blame!. In Computing, an interrupt is an asynchronous signal from hardware indicating the need for attention or a synchronous event in software indicating the need for a change POKEY had four semi-independent audio channels, each with its own frequency, noise and volume control. Each 8-bit channel had its own audio control register which selected the noise content and volume. For higher sound resolution (quality), two of the audio channels could be combined for more accurate sound (16-bit). The name POKEY comes from the words "POtentiometer" and "KEYboard", which were two of the I/O devices that POKEY interfaced with (the potentiometer is the mechanism used by the paddle). 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 This chip was actually used in several Atari arcade machines of the 80s.

Computer models

• 400 and 800 (1979) – original machines in beige cases, 400 had membrane keyboard, 800 had full-travel keys, two cartridge ports, monitor output, expandable memory slots (up to 48 KB). 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 Later PAL versions had the 6502C processor.
• 1200XL (1982) – new aluminum and smoked plastic cases, 64 KB of RAM, only two joystick ports. Help key, four function keys. A new OS caused compatibility problems with some older software.
• 600XL and 800XL (1983) – replacements for the 400, 800 and 1200XL sans function keys. 600XL had 16 KB of memory, PAL versions had a monitor port, 800XL had 64 KB and monitor output. Both had built-in BASIC and an expansion port known as the Parallel Bus Interface (PBI). The Parallel Bus Interface or PBI is a 50-pin port found on some Atari 8-bit XL computers
• 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 came with 128 KB of RAM and a Enhanced Cartridge Interface (ECI) instead of a PBI. The Enhanced Cartridge Interface or ( ECI) was a 14-pin extension to the cartridge slot on Atari 8-bit XE computers The U. S. /Canadian version of the 65XE had no ECI or PBI.
• XEGS (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, FREDDIE chip, built-in modem and speech synthesis chip. FREDDIE was the name for a 40-pin LSI found in Atari 8-bit computers 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. The 80186 is a Microprocessor that was developed by Intel circa 1982. [2]
  • 900XLF – redesigned 800XLF. Became the 65XE.
  • 65XEM – 65XE with AMY sound synthesis chip. Cancelled.
  • 65XEP – "portable" 65XE with 3. 5" disk drive, 5" green CRT and battery pack. The cathode ray tube (CRT is a Vacuum tube containing an Electron gun (a source of electrons and a Fluorescent screen with internal or Never released
  • 1090XL expansion system, 5 slots in a large case (never released, small numbers leaked out)
  • 1055 3½" floppy drive[3]
  • XF351 3½" floppy drive[4]
  • XF354 3½" floppy drive

Peripherals

Main article: Atari 8-bit computer peripherals

Atari 1020 4-color Plotter

During the lifetime of their 8-bit series, Atari released a large number of peripherals. This article covers the range of peripherals available for Atari's 8-bit home computer range (including the 400/800 XL and XE series machines These included:-

• Several dedicated cassette tape drives. All were similar, and capable of recording at 600 bit/s on a standard audio cassette. The Compact Cassette, often referred to as audio cassette, cassette tape, cassette, or simply tape, is a Magnetic tape sound (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. A floppy disk is an increasingly Obsolete data storage medium that is composed of a disk of thin flexible ("floppy" Magnetic storage medium encased
• Several printers 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 Centronics/RS-232 expansion system, numeric keypad, memory module, touch tablet and an 80-column display module. Centronics Data Computer Corporation was a pioneering American manufacturer of computer printers now remembered primarily for the parallel interface that bears its name In Telecommunications, RS-232 (Recommended Standard 232 is a standard for serial binary data signals connecting between a DTE ( Data Terminal Equipment

Atari's peripherals used the proprietary SIO port, which allowed them to be daisy chained together into a single string; a method also used in Commodore's home computers from the VIC-20 onwards. The VIC-20 ( Germany: VC-20; Japan: VIC-1001) is an 8-bit Home computer which was sold by Commodore Business Machines These "intelligent" peripherals were more expensive than the standard IBM PC devices, which did not need the added SIO electronics.

Software

Operating system

Built-in

The startup screen of early Atari 8-bit models when no program is loaded.

The startup screen when ATARI BASIC is selected.

The Atari 8-bit computers came with an operating system built into the ROM. 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 built-in Atari BASIC. For the version of BASIC bundled with the Atari ST computer series see Atari ST BASIC. Early models came with the notoriously buggy revision B. Later models used revision C.

Disk Operating System

Main article: Atari DOS

The standard Atari OS only contained very low-level routines for accessing floppy disk drives. Atari DOS is the Disk operating system used with the Atari 8-bit family of computers A floppy disk is an increasingly Obsolete data storage medium that is composed of a disk of thin flexible ("floppy" Magnetic storage medium encased An extra layer, a disk operating system, was required to assist in organizing file system-level disk access. In Computing, a file system (often also written as filesystem) is a method for storing and organizing Computer files and the data they contain to make 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. Atari DOS is the Disk operating system used with the Atari 8-bit family of computers 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. Atari DOS is the Disk operating system used with the Atari 8-bit family of computers
• 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. Atari DOS is the Disk operating system used with the Atari 8-bit family of computers

Other software

Main article: Atari 8-bit computer software

Amongst the many pieces of software released for the 8-bit Atari computers, a large number of programming languages were implemented, including:-

• Assemblers, via the Atari Assembler Editor, Atari Macro Assembler, MAC/65, and several others. This article covers various significant pieces of software available for the Atari 8-bit home computers (400/800 XL and XE series See the terminology section below for information regarding inconsistent use of the terms assembly and assembler Details The program was a two-pass 6502 assembler in an 8 KB cartridge Features MAC/65 featured two-pass compiling with a third-pass for macros
• BASIC; Atari BASIC was the "standard" BASIC implementation for the 8-bit family, originally a ROM cartridge, and built-in from the 600XL/800XL onwards. In Computer programming, BASIC (an Acronym for Beginner's All-purpose Symbolic Instruction Code) is a family of High-level programming languages For the version of BASIC bundled with the Atari ST computer series see Atari ST BASIC. Other BASICs included Atari Microsoft BASIC, Turbo Basic XL, BASIC XL and Advan BASIC. This article is about Turbo-Basic XL, a BASIC dialect for the Atari 8-bit family
• C (Programming Language), via the Deep Blue C and Lightspeed C compiler. tags please moot on the talk page first! --> In Computing, C is a general-purpose cross-platform block structured
• Other languages including LOGO (Atari LOGO), LISP (INTER-LISP/65), PILOT (Atari PILOT), several versions each of Forth and Pascal, Action! (a high performance Atari-specific language from OSS), and WSFN (which stands for nothing). Logo is a Computer programming language used for Functional programming. See also Logo programming language Lisp (or LISP) is a family of Computer Programming languages with a long history and a distinctive fully parenthesized syntax The name PILOT is an Acronym, and stands for P rogrammed I nstruction L earning O r T eaching. Forth is a structured, imperative, stack-based, computer Programming language and programming environment Pascal is an influential imperative and procedural Programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small Data Types Action! has three numerical Datatypes BYTEs CARDinals and INTegers WSFN ("Which Stands for Nothing" was a Programming language for controlling Robots created by Li-Chen Wang and published by Dr

More recently, cross platform development tools (most commonly run on PCs), have become popular for retrocomputing software development. IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. Retrocomputing is a term used to describe the use of early computer hardware and software today

Graphics capabilities

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.

• 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 registered 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

Software-driven modes

Main article: Software-driven graphics modes for the Atari 8-bit computers

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. This article describes software driven graphics modes for the Atari 8-bit computers; that is pseudo-graphics modes whose capabilities are reliant on additional software These included pseudo-256-color 80x192 modes and 80x24 character displays.

See also

• A.N.A.L.O.G. magazine
• ANTIC (magazine)
• Atari User magazine
• History of Atari
• Page 6 (computer magazine)

Footnotes

References

• The Atari 800 Personal Computer System, by the Atari Museum, accessed August 28, 2005

External links

General

• The Atari History Museum
• Atari 8-Bit Computers: Frequently Asked Questions
• http://www.atari8bit.org/
• The Atari 8-bit Computer WebRing
• Stan Veit's Atari 800 History

Technical information

• Atari Technical Information
• ANTIC Chip data sheet
• GTIA Chip data sheet
• CGIA Chip data sheet
• POKEY Chip data sheet
• Another source of chipset information

Software, games, music

• 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