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The Apple II (often rendered or written as Apple ][ or Apple //) was one of the first highly successful mass produced microcomputer products[1], manufactured by Apple Computer (now Apple Inc.) and introduced in 1977. It was among the first home computers on the market, and became one of the most recognizable and successful. In terms of ease of use, features and expandability the Apple II was a major technological advancement over its predecessor, the Apple I, a limited production bare circuit board computer for electronics hobbyists which pioneered many features that made the Apple II a commercial success. Introduced at the West Coast Computer Faire in 1977, the Apple II was among the first successful personal computers and responsible for launching the Apple company into a successful business (and for allowing several related companies to start at all). Throughout the years, a number of different models were introduced and sold, with the most popular model manufactured having relatively minor changes even into the 1990s. By the end of its production in 1993, somewhere between five and six million Apple II series computers (including approximately 1.25 million Apple IIGS models) had been produced.
The Apple II (often rendered or written as Apple ][ or Apple //) was one of the first highly successful mass produced microcomputer products[1], manufactured by Apple Computer (now Apple Inc.) and introduced in 1977. It was among the first home computers on the market, and became one of the most recognizable and successful. In terms of ease of use, features and expandability the Apple II was a major technological advancement over its predecessor, the Apple I, a limited production bare circuit board computer for electronics hobbyists which pioneered many features that made the Apple II a commercial success. Introduced at the West Coast Computer Faire in 1977, the Apple II was among the first successful personal computers and responsible for launching the Apple company into a successful business (and for allowing several related companies to start at all). Throughout the years, a number of different models were introduced and sold, with the most popular model manufactured having relatively minor changes even into the 1990s. By the end of its production in 1993, somewhere between five and six million Apple II series computers (including approximately 1.25 million Apple IIGS models) had been produced.
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Throughout the late 1980s and much of the 1990s the Apple II was the standard computer in American education.[citation needed] It was popular with business users, families, and schools, particularly after the 1979 release of the popular VisiCalc spreadsheet for Apple II. The original Apple II operating system was only the built-in BASIC interpreter contained in ROM; most commercial Apple II software on disk, e.g. educational games and productivity programs, booted directly on the hardware and either had no operating system or incorporated one of its own (which was usually invisible to the user.) The Apple DOS Disk Operating System was added to support the diskette drive; the last version was "Apple DOS 3.3". Apple DOS was superseded by ProDOS, which supported a hierarchical filesystem and larger storage devices. With an optional third-party Z80 based expansion card[3] the Apple II could boot into the CP/M operating system and run Wordstar, dBase II, and other CP/M software. At the height of its evolution, towards the late 1980s, the platform had the graphical look of a hybrid of the Apple II and Macintosh with the introduction of the Apple IIGS. By 1992 the platform had 16-bit processing capabilities, a mouse-driven Graphical User Interface, and graphic and sound capabilities far beyond the original.
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Throughout the late 1980s and much of the 1990s the Apple II was the standard computer in American education.[citation needed] It was popular with business users, families, and schools, particularly after the 1979 release of the popular VisiCalc spreadsheet for Apple II. The original Apple II operating system was only the built-in BASIC interpreter contained in ROM; most commercial Apple II software on disk, e.g. educational games and productivity programs, booted directly on the hardware and either had no operating system or incorporated one of its own (which was usually invisible to the user.) The[[Apple DOS| Apple DOS]] Disk Operating System was added to support the diskette drive; the last version was "Apple DOS 3.3". Apple DOS was superseded by [[ProDOS]], which supported a hierarchical filesystem and larger storage devices. With an optional third-party Z80 based expansion card[3] the Apple II could boot into the CP/M operating system and run Wordstar, dBase II, and other CP/M software. At the height of its evolution, towards the late 1980s, the platform had the graphical look of a hybrid of the Apple II and Macintosh with the introduction of the [[Apple IIGS]]. By 1992 the platform had 16-bit processing capabilities, a mouse-driven Graphical User Interface, and graphic and sound capabilities far beyond the original.
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The expensive GUI-based Apple Lisa was introduced in 1983, but was not successful commercially. The Macintosh was introduced in 1984, and finally eclipsed the Apple II series in 1993. Even after the introduction of the Macintosh, the Apple II series was Apple's primary revenue source for years: with its associated community of third-party developers and retailers it was once a billion-dollar-a-year industry. The Apple IIGS was sold until the end of 1992; the last II-series Apple in production, the IIe, was discontinued on October 15, 1993.
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The expensive GUI-based Apple [[Lisa|Lisa ]]was introduced in 1983, but was not successful commercially. The Macintosh was introduced in 1984, and finally eclipsed the Apple II series in 1993. Even after the introduction of the Macintosh, the Apple II series was Apple's primary revenue source for years: with its associated community of third-party developers and retailers it was once a billion-dollar-a-year industry. The Apple IIGS was sold until the end of 1992; the last II-series Apple in production, the IIe, was discontinued on October 15, 1993.
== Models ==
== Models ==
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=== Apple II ===
=== Apple II ===
The first Apple II computers went on sale on June 5, 1977 with a MOS Technology 6502 microprocessor running at 1 MHz, 4 kB of RAM, an audio cassette interface for loading programs and storing data, and the Integer BASIC programming language built into the ROMs. The video controller displayed 24 lines by 40 columns of monochrome, upper-case-only text on the screen, with NTSC composite video output suitable for display on a TV monitor, or on a regular TV set by way of a separate RF modulator. The original retail price of the computer was US$1298 (with 4 kB of RAM) and US$2638 (with the maximum 48 kB of RAM). To reflect the computer's color graphics capability, the Apple logo on the casing was represented using rainbow stripes, which remained a part of Apple's corporate logo until early 1998. The earliest Apple II's were assembled in Silicon Valley, and later in Texas; printed circuit boards were manufactured in Ireland and Singapore.
The first Apple II computers went on sale on June 5, 1977 with a MOS Technology 6502 microprocessor running at 1 MHz, 4 kB of RAM, an audio cassette interface for loading programs and storing data, and the Integer BASIC programming language built into the ROMs. The video controller displayed 24 lines by 40 columns of monochrome, upper-case-only text on the screen, with NTSC composite video output suitable for display on a TV monitor, or on a regular TV set by way of a separate RF modulator. The original retail price of the computer was US$1298 (with 4 kB of RAM) and US$2638 (with the maximum 48 kB of RAM). To reflect the computer's color graphics capability, the Apple logo on the casing was represented using rainbow stripes, which remained a part of Apple's corporate logo until early 1998. The earliest Apple II's were assembled in Silicon Valley, and later in Texas; printed circuit boards were manufactured in Ireland and Singapore.
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An external 5¼-inch floppy disk drive, the Disk II, attached via a controller card that plugged into one of the computer's expansion slots (usually slot 6), was used for data storage and retrieval to replace cassettes. The Disk II interface, created by Steve Wozniak, was regarded as an engineering masterpiece at the time for its economy of electronic components.While other controllers had dozens of chips for synchronizing data I/O with disk rotation, seeking the head to the appropriate track, and encoding the data into magnetic pulses, Wozniak's controller card had few chips; instead, the Apple DOS used software to perform these functions. The Group Code Recording used by the controller was simpler and easier to implement in software than the more common MFM. In the end, the low chip count of the controller contributed to making Apple's Disk II the first affordable floppy drive system for personal computers. As a side effect, Wozniak's scheme made it easy for proprietary software developers to copy-protect the media on which their software shipped by changing the low-level sector format or stepping the drive's head between the tracks; inevitably, other companies eventually sold software to foil this protection. Another Wozniak optimization allowed him to omit Shugart's Track-0 sensor. When the Operating System wants to go to track 0, the controller simply moves forty times toward the next-lower-numbered track, relying on the mechanical stop to prevent it going any further down than track 0. This process, called "recalibration", made a loud buzzing (rapid mechanical chattering) sound that often frightened Apple novices.
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An external 5¼-inch floppy disk drive, the [[Disk II]], attached via a controller card that plugged into one of the computer's expansion slots (usually slot 6), was used for data storage and retrieval to replace cassettes. The Disk II interface, created by Steve Wozniak, was regarded as an engineering masterpiece at the time for its economy of electronic components.While other controllers had dozens of chips for synchronizing data I/O with disk rotation, seeking the head to the appropriate track, and encoding the data into magnetic pulses, Wozniak's controller card had few chips; instead, the Apple DOS used software to perform these functions. The Group Code Recording used by the controller was simpler and easier to implement in software than the more common MFM. In the end, the low chip count of the controller contributed to making Apple's Disk II the first affordable floppy drive system for personal computers. As a side effect, Wozniak's scheme made it easy for proprietary software developers to copy-protect the media on which their software shipped by changing the low-level sector format or stepping the drive's head between the tracks; inevitably, other companies eventually sold software to foil this protection. Another Wozniak optimization allowed him to omit Shugart's Track-0 sensor. When the Operating System wants to go to track 0, the controller simply moves forty times toward the next-lower-numbered track, relying on the mechanical stop to prevent it going any further down than track 0. This process, called "recalibration", made a loud buzzing (rapid mechanical chattering) sound that often frightened Apple novices.
The approach taken in the Disk II controller was typical of Wozniak's design sensibility. The Apple II used several engineering shortcuts to save hardware and reduce costs. For example, taking advantage of the way that 6502 instructions only access memory every other clock cycle, the video generation circuitry's memory access on the otherwise unused cycles avoided memory contention issues and also eliminated the need for a separate refresh circuit for the DRAM chips. Rather than using a complex analog-to-digital circuit to read the outputs of the game controller, Wozniak used a simple timer circuit whose period was proportional to the resistance of the game controller, and used a software loop to measure the timer.
The approach taken in the Disk II controller was typical of Wozniak's design sensibility. The Apple II used several engineering shortcuts to save hardware and reduce costs. For example, taking advantage of the way that 6502 instructions only access memory every other clock cycle, the video generation circuitry's memory access on the otherwise unused cycles avoided memory contention issues and also eliminated the need for a separate refresh circuit for the DRAM chips. Rather than using a complex analog-to-digital circuit to read the outputs of the game controller, Wozniak used a simple timer circuit whose period was proportional to the resistance of the game controller, and used a software loop to measure the timer.
The text and graphics screens had a somewhat outdated arrangement (the scanlines were not stored in sequential areas of memory) which was reputedly due to Wozniak's realization that doing it that way would save a chip; it was less expensive to have software calculate or look up the address of the required scanline than to include the extra hardware. Similarly, in the high-resolution graphics mode, color was determined by pixel position and could thus be implemented in software, saving Wozniak the chips needed to convert bit patterns to colors. This also allowed for sub-pixel font rendering since orange and blue pixels appeared half a pixel-width further to the right on the screen than green and purple pixels.
The text and graphics screens had a somewhat outdated arrangement (the scanlines were not stored in sequential areas of memory) which was reputedly due to Wozniak's realization that doing it that way would save a chip; it was less expensive to have software calculate or look up the address of the required scanline than to include the extra hardware. Similarly, in the high-resolution graphics mode, color was determined by pixel position and could thus be implemented in software, saving Wozniak the chips needed to convert bit patterns to colors. This also allowed for sub-pixel font rendering since orange and blue pixels appeared half a pixel-width further to the right on the screen than green and purple pixels.
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Color on the Apple II series took advantage of a quirk of the NTSC television signal standard, which made color display relatively easy and inexpensive to implement. The original NTSC television signal specification was black-and-white. Color was tacked on later by adding a 3.58 MHz subcarrier signal that was partially ignored by B&W TV sets. Color is encoded based on the phase of this signal in relation to a reference color burst signal. The result is that the position, size, and intensity of a series of pulses define color information.
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Color on the Apple II series took advantage of a quirk of the NTSC television signal standard, which made color display relatively easy and inexpensive to implement. The original NTSC television signal specification was black-and-white. Color was tacked on later by adding a 3.58 MHz subcarrier signal that was partially ignored by B&W TV sets. Color is encoded based on the phase of this signal in relation to a reference color burst signal. The result is that the position, size, and intensity of a series of pulses define color information.
=== Apple II Plus ===
=== Apple II Plus ===