Atari 8-bit family
The Atari 8-bit family is a series of 8-bit home computers introduced by Atari, Inc. in 1979 and manufactured until 1992. All of the machines in the family are technically similar and differ in packaging, they are based on the MOS Technology 6502 CPU running at 1.79 MHz, were the first home computers designed with custom co-processor chips. This architecture enabled graphics and sound capabilities that were more advanced than contemporary machines at the time of release, gaming on the platform was a major draw. Star Raiders is considered the platform's killer app; the original Atari 400 and 800 models launched with a series of plug-n-play peripherals that used the Atari SIO serial bus system, an early analog of the modern USB. To meet stringent FCC requirements, the early machines were enclosed in a cast aluminum block, which made them physically robust but expensive to produce. Over the following decade, the 400 and 800 were replaced by the XL series the XE; the XL and XE are much lighter in construction and less expensive to build, while having Atari BASIC built-in and reducing the number of joystick ports from 4 to 2.
The 130XE, released in 1985, increased the memory to 128K of bank-switched RAM. The Atari 8-bit computer line sold two million units during its major production run between late 1979 and mid-1985, they were not only sold through dedicated computer retailers, but department stores such as Sears, using an in-store demo to attract customers. The primary competition in the worldwide market came several years when the Commodore 64 was introduced in 1982; this was the first computer to offer similar graphics performance, went on to be the best selling computer of the 8-bit era. Atari found a strong market in Eastern Europe and had something of a renaissance in the early 1990s as these countries joined a uniting Europe. In 1992, Atari Corp. dropped all remaining support of the 8-bit line. Some time in 1975, Steve Jobs called his former boss at Atari, Al Alcorn, Vice President of Engineering. Jobs was sourcing components for the soon-to-released Apple II, asked Alcorn if he knew of a good switched mode power supply.
Such devices were commercially available. Alcorn instead suggested. Holt worked in Atari's consumer division and had become a leading expert on power supplies, at that time was between projects. Instead, Jobs hired Holt away from Atari, offering him "a ton of stock". Jobs began hiring many Atari engineers and refused to stop this behaviour when asked. In response, Joe Keenan, one of Atari's co-founders, began a project to make an Apple II clone machine, which Atari could produce for much less than Apple, they began design work. It was not long after that news of this project reached Jobs, two weeks he agreed to stop poaching Atari staff; the project was cancelled, ending Atari's first attempt at a personal computer. Design of the 8-bit series of machines started at Atari as soon as the Atari 2600 games console was released in late 1977. While designing the 2600 in 1976, the engineering team from Atari Grass Valley Research Center 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 1979. What they ended up with was a updated version of the 2600, fixing its more obvious limitations but sharing a similar overall design philosophy; the newer design would be faster than the 2600, have better graphics, would include much better sound hardware. Work on the chips for the new system continued throughout 1978 and focused on much-improved video hardware known as the CTIA. During the early development period, the home computer era began in earnest in the form of the TRS-80, Commodore PET, Apple II family—what Byte Magazine would dub the "1977 Trinity". Nolan Bushnell sold Atari to Warner Communications for $28 million in 1976 in order to raise funds for the launch of the 2600. Warner had sent Ray Kassar to act as the CEO of the company. Kassar felt. In order to adapt the machine to this role, it would need to support character graphics, include some form of expansion for peripherals, run the then-universal BASIC programming language.
The 2600 had no bitmap graphics support or a character generator, all on-screen graphics were created using Player-Missile graphics and a simple background using fixed patterns. The CTIA was designed on the same model, mainly used sprites for drawing. Instead of expanding the CTIA to handle these tasks, the designers introduced an new chip for this purpose, the Alphanumeric Television Interface Controller, or ANTIC; the CTIA and ANTIC worked together to produce a complete display, with the CTIA in charge of sprites and producing color video output, the ANTIC in charge of bitmap and character graphics. Management identified two sweet spots for the new computers: a low-end version known as "Candy", a higher-end machine known as "Colleen"; the primary difference between the two models was marketing. Colleen included user-accessible expansion slots for RAM and ROM, two 8 KB ROM cartridge slots, RF and monitor output and a full keyboard. Candy was designed as a games console, lacking a keyboard and input/output ports, although an external keyboard was planned tha
Graphics Environment Manager
GEM was an operating environment created by Digital Research for use with the DOS operating system on Intel 8088 and Motorola 68000 microprocessors. GEM is known as the graphical user interface for the Atari ST series of computers, was supplied with a series of IBM PC-compatible computers from Amstrad, it was available for the standard IBM PC, at a time when the 6 MHz IBM PC AT was brand new. It was the core for a small number of DOS programs, it was ported to a number of other computers that lacked graphical interfaces, but never gained popularity on those platforms. DRI produced X/GEM for their FlexOS real-time operating system with adaptations for OS/2 Presentation Manager and the X Window System under preparation as well. GEM started life at DRI as a more general-purpose graphics library known as GSX, written by a team led by Don Heiskell. Lee Lorenzen who had left Xerox PARC wrote much of the code. GSX was a DRI-specific implementation of the GKS graphics standard proposed in the late 1970s.
GSX was intended to allow DRI to write graphics programs for any of the platforms CP/M-80, CP/M-86 and MS-DOS would run on, a task that would otherwise require considerable effort to port due to the large differences in graphics hardware between the various systems of that era. GSX consisted of two parts: a selection of routines for common drawing operations, the device drivers that are responsible for handling the actual output; the former was known as GDOS and the latter as GIOS, a play on the division of CP/M into machine-independent BDOS and machine-specific BIOS. GDOS was a selection of routines that handled the GKS drawing, while GIOS used the underlying hardware to produce the output. DDFXLR7 Epson and Epson-compatible printers DDFXLR8 Epson lo-res, 8-bit DDFXHR8 Epson hi-res, 8-bit DD-DMP1 Amstrad DMP1 printer DDSHINWA Printers using Shinwa Industries mechanism DDHP7470 DD7470 Hewlett Packard HP 7470 and compatible pen plotters, HP-GL/2 DDMODE0 Amstrad CPC screen in mode 0 DDMODE1 Amstrad CPC screen in mode 1 DDMODE2 Amstrad CPC screen in mode 2 DDSCREEN Amstrad PCW screen DD7220 Hewlett Packard HP 7220, HP-GL DDGDC DDNCRDMV NEC µPD7220 DDGEN2 Retro-Graphics GEN.
II DDHI3M Houston Instrument HiPlot DMP DDHI7M Houston Instrument HiPlot DMP DDMX80 Epson MX-80 + Graftrax Plus DDVRET VT100 + Retro-Graphics GEN. II DDQX10 QX-10 screen DDCITOH C. Itoh 8510A DDESP Electric Studio Light Pen DDOKI84 Oki Data Microline DDBBC0 BBC Micro screen in mode 0 DDBBC1 BBC Micro screen in mode 1 DDCITOLR C. Itoh 8510A lo-res DDTS803 TeleVideo screen DDANADXM Anadex DP-9501 and DP-9001A DDCITOLR C. Itoh 8510A lo-res DDCNTXM Centronics 351, 352 and 353 DDDS180 Datasouth DDIDSM IDS Monochrome DDLA100 DEC DDLA50 DEC DDOKI84 Oki Data Microline DDPMVP Printronix MVP DD3EPSNL IBM/Epson FX-80 lo-res Printer, see DDFXLR7 and DDFXLR8 DD3EPSNH IBM/Epson FX-80 hi-res Printer, see DDFXHR8 DD75XHM1 Regnecentralen RC759 Piccoline DDNECAPC NEC APC DDGSXM Metafile NCRPC4 NCR DecisionMate V IBMBLMP2 IBMBLMP3 IBM CGA monochrome mode IBMBLCP2 IBMBLCP3 IBM CGA color mode IBMHP743 Hewlett-Packard 7470A/7475A Plotter, see DDHP7470 and DD7470 HERMONP2 IBMHERP3 Hercules monochrome graphics PALETTE Polaroid cameraThe same driver binary may operate under both CP/M-86 and DOS.
GSX evolved into one part of what would be known as GEM, an effort to build a GUI system using the earlier GSX work as its basis. Known as Crystal as a play on an IBM project called Glass, the name was changed to GEM. Under GEM, GSX became GEM VDI, responsible for basic graphics and drawing. VDI added the ability to work with multiple fonts and added a selection of raster drawing commands to the vector-only GKS-based drawing commands. VDI added multiple viewports, a key addition for use with windows. A new module, GEM AES, provided the window management and UI elements, GEM Desktop used both libraries in combination to provide a GUI; the 8086 version of the entire system was first demoed at the 1984 COMDEX, shipped as GEM/1 on 28 February 1985. GEM Desktop 1.0 was released on 28 February 1985. GEM Desktop 1.1 was released in 1985, with support for CGA and EGA displays. A version for the Apricot Computers F-Series, supporting 640×200 in up to 8 colors was available as GEM Desktop 1.2. DRI designed GEM for DOS so that it would check for and only run on IBM computers, not PC compatibles like those from Compaq, as the company hoped to receive license fees from compatible makers.
Developers reacted with what BYTE described as "a small explosion". That month the company removed the restriction. Applications that supported GEM included Lifetree Software's GEM Write. At this point, Apple Computer sued DRI in what would turn into a long dispute over the "look and feel" of the GEM/1 system, an direct copy of Macintosh; this led to DRI being forced to change several basic features of the system. Apple would go on to sue other companies for similar issues, including their copyright lawsuit against Micro
Gary Arlen Kildall was an American computer scientist and microcomputer entrepreneur who created the CP/M operating system and founded Digital Research, Inc.. Kildall was one of the first people to see microprocessors as capable computers rather than equipment controllers and to organize a company around this concept, he co-hosted the PBS TV show The Computer Chronicles. Although his career in computing spanned more than two decades, he is remembered in connection with IBM's unsuccessful attempt in 1980 to license CP/M for the IBM PC. Gary Kildall was born and grew up in Seattle, where his family operated a seafaring school, his father, Joseph Kildall, was a captain of Norwegian heritage. His mother Emma was half-Swedish—Gary's grandmother was born in Långbäck, Sweden, in Skellefteå Municipality but emigrated to Canada at 23 years of age. Gary attended the University of Washington hoping to become a mathematics teacher, but became interested in computer technology. After receiving his degree, he fulfilled a draft obligation to the United States Navy by teaching at the Naval Postgraduate School in Monterey, California.
Being within an hour's drive of Silicon Valley, Kildall heard about the first commercially available microprocessor, the Intel 4004. He began writing experimental programs for it. To learn more about the processors, he worked at Intel as a consultant on his days off. Kildall returned to UW and finished his doctorate in computer science in 1972 resumed teaching at NPS, he published a paper that introduced the theory of data-flow analysis used today in optimizing compilers, he continued to experiment with microcomputers and the emerging technology of floppy disks. Intel lent him systems using the 8008 and 8080 processors, in 1973, he developed the first high-level programming language for microprocessors, called PL/M, he created CP/M the same year to enable the 8080 to control a floppy drive, combining for the first time all the essential components of a computer at the microcomputer scale. He demonstrated CP/M to Intel. Kildall and his wife Dorothy established a company called "Intergalactic Digital Research", to market CP/M through advertisements in hobbyist magazines.
Digital Research licensed CP/M for the IMSAI 8080, a popular clone of the Altair 8800. As more manufacturers licensed CP/M, it became a de facto standard and had to support an increasing number of hardware variations. In response, Kildall pioneered the concept of a BIOS, a set of simple programs stored in the computer hardware that enabled CP/M to run on different systems without modification. CP/M's quick success took Kildall by surprise, he was slow to update it for high density floppy disks and hard disks. After hardware manufacturers talked about creating a rival operating system, Kildall started a rush project to develop CP/M 2. By 1981, at the peak of its popularity, CP/M ran on 3,000 different computer models and DRI had $5.4 million in yearly revenues. IBM, presided by John R. Opel, approached Digital Research in 1980, at Bill Gates' suggestion, to negotiate the purchase of a forthcoming version of CP/M called CP/M-86 for the IBM PC. Gary had left negotiations to his wife, Dorothy, as he did, while he and colleague and developer of MP/M operating system Tom Rolander used Gary's private airplane to deliver software to manufacturer Bill Godbout.
Before the IBM representatives would explain the purpose of their visit, they insisted that Dorothy sign a non-disclosure agreement. On the advice of DRI attorney Gerry Davis, Dorothy refused to sign the agreement without Gary's approval. Gary returned in the afternoon and tried to move the discussion with IBM forward, but accounts disagree on whether he signed the non-disclosure agreement, as well as if he met with the IBM representatives. Various reasons have been given for the two companies failing to reach an agreement. DRI, which had only a few products, might have been unwilling to sell its main product to IBM for a one-time payment rather than its usual royalty-based plan. Dorothy might have believed that the company could not deliver CP/M-86 on IBM's proposed schedule, as the company was busy developing an implementation of the PL/I programming language for Data General. Or, the IBM representatives might have been annoyed that DRI had spent hours on what they considered a routine formality.
According to Kildall, the IBM representatives took the same flight to Florida that night that he and Dorothy took for their vacation, they negotiated further on the flight, reaching a handshake agreement. IBM lead negotiator Jack Sams insisted that he never met Gary, one IBM colleague has confirmed that Sams said so at the time, he accepted that someone else in his group might have been on the same flight, but noted that he flew back to Seattle to talk with Microsoft again. Sams related the story to Gates, who had agreed to provide a BASIC interpreter and several other programs for the PC. Gates' impression of the story was that Gary capriciously "went flying", as he would tell reporters. Sams left Gates with the task of finding a usable operating system, a few weeks he proposed using the operating system 86-DOS—an independently developed operating system that implemented Kildall's CP/M API—from Seattle Computer Products. Paul Allen negotiated a licensing deal with SCP. Allen had 86-DOS adapted for IBM's hardware, IBM shipped it as PC DOS.
Kildall obtained a copy of PC DOS, examined it, concluded that it infringed on CP/M. When he asked Gerry Davis what legal options were available, Davis told him that intellectual property law for
Atari, Inc. was an American video game developer and home computer company founded in 1972 by Nolan Bushnell and Ted Dabney. 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 American video game crash of 1983. In 1966, Nolan Bushnell saw Spacewar! for the first time at the University of Utah. By 1968, Bushnell had become an employee of Ampex in San Francisco, worked alongside Ted Dabney; the two found they had shared interests, including the game Go, Bushnell shared with Dabney his gaming-pizza parlor idea, had taken him to the computer lab at Stanford Artificial Intelligence Laboratory to see the games on those systems. They jointly developed the concept of using a standalone computer system with a monitor and attaching a coin slot to it to play games on. Bushnell and Dabney worked with Nutting Associates to manufacture their product. Dabney developed a method of using video circuitry components to mimic functions of a computer for a much cheaper cost and a smaller space.
Bushnell and Dabney used this to develop a variation on Spacewar! called Computer Space where the player shot at two orbiting UFOs. Nutting helped to manufacture the fiberglass cabinet. While they were developing this, they took on duties under Nutting to repair pinball machines. Computer Space did not fare well commercially when it was placed in Nutting's customary market, bars. Feeling that the game was too complex for the average customer unfamiliar and unsure with the new technology, Bushnell started looking for new ideas, they decided to start a separate venture called the Syzygy Game Company, each putting in US$250 of their own funds to support it. They subsequently made sure that Nutting used "Syzygy Engineering" labels on each Computer Space game sold to reflect their work in the game. Bushnell began seeking other partners outside of Nutting, approached pinball game manufacturer Bally Manufacturing, who indicated interest in funding future efforts in arcade games by Bushnell and Dabney if Nutting was not involved.
The two quit established offices for Syzygy in Sunnyvale. Bally offered them a US$4,000 a month for six months to design a new video game and a new pinball machine. With those funds, they hired Al Alcorn as their first design engineer. Wanting to start Syzygy off with a driving game, Bushnell had concerns that it might be too complicated for the young Alcorn's first game. In May 1972, Bushnell had seen a demonstration of the Magnavox Odyssey, which included a tennis game. According to Alcorn, Bushnell decided to have him produce an arcade version of the Odyssey's Tennis game, which would go on to be named Pong. Bushnell had Alcorn use Dabney's video circuit concepts to help develop the game, believing it would be a first prototype, but Alcorn's success impressed both Bushnell and Dabney, leading them to believe they had a major success on hand and prepared to offer the game to Bally as part of the contract. In anticipation and Dabney went to incorporate the firm, but found that Syzygy existed in California.
Bushnell wrote down several words from Go choosing atari, a term that in the context of the game means a state where a stone or group of stones is imminently in danger of being taken by one's opponent. Atari was incorporated in the state of California on June 27, 1972. Bushnell and Dabney offered to license Pong to Bally, but the company had no idea what to do with the game, did not take the license. Instead and Dabney opted to create a test unit themselves and see how it was received at a local establishment. By August 1972, the first Pong was completed, it consisted of a black and white television from Walgreens, the special game hardware, a coin mechanism from a laundromat on the side which featured a milk carton inside to catch coins. It was placed in a Sunnyvale tavern by the name of Andy Capp's to test its viability; the Andy Capp test was successful, so the company created twelve more test units, ten which were distributed across other local bars. They found, they reported these numbers to Bally.
Bushnell and Dabney realized that they needed to expand on the game but formally needed to get out of their contract with Bally. Bushnell told Bally that they could offer to make another game for them, but only if they rejected Pong. After talks to release Pong through Nutting and several other companies broke down and Dabney decided to release Pong on their own, Atari, Inc. was established as a coin-op design and production company. Around 1973, Dabney felt. In March 1973, Dabney formally left Atari, selling his portion of the company for US$250,000. While Dabney would continue to work for Bushnell on other ventures, including Bushnell's Pizza Time Theater, the predecessor to Chuck E. Cheese's, he had a falling out with Bushnell and left the video game industry. Dabney's contributions towards Atari's founding generally
Apple Pascal is an implementation of Pascal for the Apple II and Apple III computer series. It's based on UCSD Pascal Just like other UCSD Pascal implementations, it ran on its own operating system. Released for the Apple II in August 1979, just after Apple DOS 3.2, Apple Pascal pioneered a number of features that would be incorporated into DOS 3.3, as well as others that would not be seen again until the introduction of ProDOS. The Apple Pascal software package included disk maintenance utilities, an assembler meant to complement the Apple's built-in "monitor" assembler. A FORTRAN compiler compiling to the same p-code as Pascal was available. Apple Pascal Operating System introduced a new disk format. Instead of dividing the disk into 256-byte sectors as in DOS 3.2, Apple Pascal divides it into "blocks" of 512 bytes each.. The p-System introduced a different method for saving and retrieving files. Under Apple DOS, files were saved to any available sector that the OS could find, regardless of location.
Over time, this could lead to file slowing access to the disk. Apple Pascal attempted to rectify this by saving only to consecutive blocks on the disk. Other innovations introduced in the file system included the introduction of a timestamp feature. Only a file's name, basic type, size would be shown. Disks could be named for the first time. Limitations of the p-System included new restrictions on the naming of files. Writing files only on consecutive blocks created problems, because over time free space tended to become too fragmented to store new files. A utility called; the biggest problem with the Apple Pascal system was. This meant. A system needed at least two disk drives. Apple. Apple II Pascal Operating System Reference Manual. Retrieved September 12, 2018. Apple. Apple III Pascal - Introduction and Editor. Retrieved September 12, 2018. Apple. Apple III Update 1.1. Retrieved September 12, 2018; the History of Apple's Pascal "Syntax" Poster, 1979-80. Pascal Syntax Poster
Atari SA is a French corporate and brand name owned by several entities since its inception in 1972 by Atari Interactive, a subsidiary of the French publisher Atari, SA. The original Atari, Inc. founded in Sunnyvale, California in 1972 by Nolan Bushnell and Ted Dabney, was a pioneer in arcade games, home video game consoles, home computers. The company's products, such as Pong and the Atari 2600, helped define the electronic entertainment industry from the 1970s to the mid-1980s. In 1984, as a result of the video game crash of 1983, the original Atari Inc. was split, the arcade division was turned into Atari Games Inc. Atari Games received the rights to use the logo and brand name with appended text "Games" on arcade games, as well as rights to the original 1972–1984 arcade hardware properties; the Atari Consumer Electronics Division properties were in turn sold to Jack Tramiel's Tramiel Technology Ltd. which renamed itself to Atari Corporation. In 1996, Atari Corporation reverse-merged with disk-drive manufacturer JT Storage, becoming a division within the company.
In 1998, Hasbro Interactive acquired all Atari Corporation related properties from JTS, creating a new subsidiary, Atari Interactive. Infogrames Entertainment bought Hasbro Interactive in 2001 and renamed it Infogrames Interactive, which intermittently published Atari branded titles. In 2003, it renamed the division Atari Interactive. Another IESA division, Infogrames Inc. changed its name to Atari Inc. the same year, licensing the Atari name and logo from its fellow subsidiary. In 2008, IESA completed its acquisition of Atari, Inc.'s outstanding stock, making it a wholly owned subsidiary. IESA renamed itself Atari, SA in 2009, it sought bankruptcy protection under French law in January 2013. In 1971, Nolan Bushnell and Ted Dabney founded a small engineering company, Syzygy Engineering, that designed and built Computer Space, the world's first commercially available arcade video game, for Nutting Associates. On June 27, 1972, the two incorporated Atari, Inc. and soon hired Al Alcorn as their first design engineer.
Bushnell asked Alcorn to produce an arcade version of the Magnavox Odyssey's Tennis game, which would be named Pong. While Bushnell incorporated Atari in June 1972, Syzygy Company was never formally incorporated. Before Atari's incorporation, Bushnell considered various terms from the game Go choosing atari, referencing a position in the game when a group of stones is imminently in danger of being taken by one's opponent. Atari was incorporated in the state of California on June 27, 1972. In 1973, Atari secretly spawned a competitor called Kee Games, headed by Nolan's next door neighbor Joe Keenan, to circumvent pinball distributors' insistence on exclusive distribution deals. Joe Keenan's management of the subsidiary led to him being promoted president of Atari that same year. In 1976, through Grass Valley, CA firm Cyan Engineering, started development of a flexible console, capable of playing the four existing Atari games; the result was the Atari Video Computer System, or AVCS. The introductory price of $199 included a console, two joysticks, a pair of paddles, the Combat game cartridge.
Bushnell knew he had another potential hit on his hands but bringing the machine to market would be expensive. Looking for outside investors, Bushnell sold Atari to Warner Communications in 1976 for an estimated $28–32 million, using part of the money to buy the Folgers Mansion. Nolan continued to have disagreements with Warner Management over the direction of the company, the discontinuation of the pinball division, most the notion of discontinuing the 2600. In 1978, Kee Games was disbanded. In December of that year, Nolan Bushnell was fired following an argument with Manny Gerard. "e started fighting like dogs. And the wheels came off that fall. Warner claimed they fired me," recalled Bushnell. "I say I quit. It was a mutual separation."Development of a successor to the 2600 started as soon as it shipped. The original team estimated. Mid-way into their effort the home computer revolution took off, leading to the addition of a keyboard and features to produce the Atari 800 and its smaller sibling, the 400.
The new machines had some success when they became available in quantity in 1980. From this platform Atari released their next-generation game console in 1982, the Atari 5200, it was unsuccessful due to incompatibility with the 2600 game library, a small quantity of dedicated games, notoriously unreliable controllers. Under Warner and Atari's chairman and CEO, Raymond Kassar, the company achieved its greatest success, selling millions of 2600s and computers. At its peak, Atari accounted for a third of Warner's annual income and was the fastest growing company in US history at the time. However, it ran into problems in the early 1980s as interference from the New York-based Warner management affected daily operations, its home computer, video game console, arcade divisions operated independently and cooperated. Faced with fierce competition and price wars in the game console and home computer markets, Atari was never able to duplicate the success of the 2600; these problems were followed by the video game crash of 1983, with losses that totaled more than $500 million.
Warner's stock price slid from $60 to $20, the company began searching for a buyer for its troubled division. In 1983, Ray Kassar had res
CP/M standing for Control Program/Monitor and Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/85-based microcomputers by Gary Kildall of Digital Research, Inc. Confined to single-tasking on 8-bit processors and no more than 64 kilobytes of memory versions of CP/M added multi-user variations and were migrated to 16-bit processors; the combination of CP/M and S-100 bus computers was loosely patterned on the MITS Altair, an early standard in the microcomputer industry. This computer platform was used in business through the late 1970s and into the mid-1980s. CP/M increased the market size for both hardware and software by reducing the amount of programming required to install an application on a new manufacturer's computer. An important driver of software innovation was the advent of low-cost microcomputers running CP/M, as independent programmers and hackers bought them and shared their creations in user groups. CP/M was displaced by DOS soon after the 1981 introduction of the IBM PC.
A minimal 8-bit CP/M system would contain the following components: A computer terminal using the ASCII character set An Intel 8080 or Zilog Z80 microprocessor The NEC V20 and V30 processors support an 8080-emulation mode that can run 8-bit CP/M on a PC DOS/MS-DOS computer so equipped, though any PC can run the 16-bit CP/M-86. At least 16 kilobytes of RAM, beginning at address 0 A means to bootstrap the first sector of the diskette At least one floppy disk driveThe only hardware system that CP/M, as sold by Digital Research, would support was the Intel 8080 Development System. Manufacturers of CP/M-compatible systems customized portions of the operating system for their own combination of installed memory, disk drives, console devices. CP/M would run on systems based on the Zilog Z80 processor since the Z80 was compatible with 8080 code. While the Digital Research distributed core of CP/M did not use any of the Z80-specific instructions, many Z80-based systems used Z80 code in the system-specific BIOS, many applications were dedicated to Z80-based CP/M machines.
On most machines the bootstrap was a minimal bootloader in ROM combined with some means of minimal bank switching or a means of injecting code on the bus. CP/M used the 7-bit ASCII set; the other 128 characters made possible by the 8-bit byte were not standardized. For example, one Kaypro used them for Greek characters, Osborne machines used the 8th bit set to indicate an underlined character. WordStar used the 8th bit as an end-of-word marker. International CP/M systems most used the ISO 646 norm for localized character sets, replacing certain ASCII characters with localized characters rather than adding them beyond the 7-bit boundary. In the 8-bit versions, while running, the CP/M operating system loaded into memory had three components: Basic Input/Output System or BIOS, Basic Disk Operating System or BDOS, Console Command Processor or CCP; the BIOS and BDOS were memory-resident, while the CCP was memory-resident unless overwritten by an application, in which case it was automatically reloaded after the application finished running.
A number of transient commands for standard utilities were provided. The transient commands resided in files with the extension. COM on disk; the BIOS directly controlled hardware components other than main memory. It contained functions such as character input and output and the reading and writing of disk sectors; the BDOS implemented the CP/M file system and some input/output abstractions on top of the BIOS. The CCP took user commands and either executed them directly or loaded and started an executable file of the given name. Third-party applications for CP/M were essentially transient commands; the BDOS, CCP and standard transient commands were the same in all installations of a particular revision of CP/M, but the BIOS portion was always adapted to the particular hardware. Adding memory to a computer, for example, meant that the CP/M system had to be reinstalled with an updated BIOS capable of addressing the additional memory. A utility was provided to patch the supplied BIOS, BDOS and CCP to allow them to be run from higher memory.
Once installed, the operating system was stored in reserved areas at the beginning of any disk which would be used to boot the system. On start-up, the bootloader would load the operating system from the disk in drive A:. By modern standards CP/M was primitive. With version 1.0 there was no provision for detecting a changed disk. If a user changed disks without manually rereading the disk directory the system would write on the new disk using the old disk's directory information, ruining the data stored on the disk. From version 1.1 or 1.2 onwards, changing a disk trying to write to it before its directory was read would cause a fatal error to be signalled. This avoided overwriting the disk but required a reboot and loss of the data, to be stored on disk; the majority of the complexity in CP/M was isolated in the BDOS, to a lesser extent, the CCP and transient commands. This meant that by porting the limited number of simple routines in the BIOS to a particular hardware platform, the entire OS would work.