|
- 〔(VAW: Pre-PowerPC Profile Specs )〕 | CPU=Synertek 6502A | CPUspeed=2 MHz | OS=Apple SOS | RAM=128 KB, expandable to 512 KB| | RAMtype= | Discontinued= }} The Apple III (often styled as Apple ///) is a business-oriented personal computer produced and released by Apple Computer that was intended as the successor to the Apple II series, but was largely considered a failure in the market. Development work on the Apple III started in late 1978 under the guidance of Dr. Wendell Sander. It had the internal code name of "Sara", named after Sander's daughter.〔Linzmayer, Owen W. (2004). ''Apple Confidential 2.0: The Definitive History of the World's Most Colorful Company'', No Starch Press. ISBN 9781593270100. p41.〕 The machine was first announced and released on May 19, 1980, but due to serious stability issues that required a design overhaul and a recall of existing machines, it was formally reintroduced in the second half of 1981.〔(Apple III computer @ oldcomputers.net )〕 Development stopped and the Apple III was discontinued on April 24, 1984, and its last successor—the III Plus, was dropped from the Apple product line in September 1985.〔 The Apple III could be viewed as an enhanced Apple II – then the newest heir to a line of 8-bit machines dating back to 1976. However, the Apple III was not part of the Apple II line, but rather a close cousin. The key features business users wanted in a personal computer were a true typewriter-style upper/lowercase keyboard (as opposed to the Apple II which was based on a Teletype keyboard) and 80-column display. In addition, the machine had to pass U.S. Federal Communications Commission (FCC) Radio Frequency Interference (RFI) qualifications for business equipment. In 1981, International Business Machines unveiled the IBM Personal Computer (IBM PC) – a completely new 16-bit design soon available in a wide range of inexpensive clones. The business market moved rapidly towards the PC DOS/MS-DOS platform, eventually pulling away from the Apple 8-bit computer line.〔(The Origin of the IBM PC )〕 Despite numerous stability issues and a recall that included the first 14,000 units off the assembly line, Apple was eventually able to produce a reliable and dependable version of the machine. However, damage to the computer's reputation had already been done and it failed to do well commercially as a direct result. In the end, an estimated 65,000–75,000 Apple III computers were sold.〔〔 The Apple III Plus brought this up to ~120,000.〔 Apple co-founder Steve Wozniak stated that the primary reason for the Apple III's failure was that the system was designed by Apple's marketing department, unlike Apple's previous engineering-driven projects.〔Wozniak, S. G. (2006), ''iWoz: From Computer Geek to Cult Icon: How I Invented the Personal Computer, Co-Founded Apple, and Had Fun Doing It''. W. W. Norton & Company. ISBN 0-393-06143-4.〕 The Apple III's failure led to Apple reevaluating their plan to phase out the Apple II, and eventual continuation of development of the older machine. As a result, later Apple II models incorporated some hardware, such as the Apple Scribe Printer, a thermal printer, and software technologies of the Apple III. ==Design== The Apple III was designed to be a business computer and an eventual successor for the Apple II. While the Apple II contributed to the inspirations of several important business products, such as VisiCalc, Multiplan and Apple Writer, the computer's hardware architecture, operating system and developer environment were limited.〔(The Apple III Project )〕 The Apple III addressed these weaknesses. According to Steve Wozniak, VisiCalc and Disk II had caused the Apple II's popularity, with 90% of sales going to businesses as opposed to the hobbyists that were its original market. Apple management intended to clearly establish market segmentation by designing the Apple III to appeal to the business market, leaving the Apple II to home and education users. Management believed that "once the Apple III was out, the Apple II would stop selling in six months", Wozniak said. The Apple III was powered by a 1.8 MHz Synertek 6502A or B 8-bit CPU and, like some of the later machines in the Apple II family, used bank switching techniques to address memory beyond the 6502's traditional 64KB limit, up to 256 K in the IIIs case. Third-party vendors also produced memory upgrade kits that allowed the Apple III to reach up to 512 KB. Other Apple III built-in features included an 80-column, 24-line display with upper and lowercase characters, a numeric keypad, dual-speed (pressure-sensitive) cursor control keys, 6-bit (DAC) audio, and a built-in 140 KB 5.25" floppy disk drive. Graphics modes included 560x192 in black and white, and 280x192 with 16 colors or shades of gray. Unlike the Apple II, the Disk III controller was built into the logic board. The Apple III was the first Apple product that allowed the user to choose both a screen font and a keyboard layout: either QWERTY or Dvorak. These choices could not be changed while programs were running, unlike the Apple IIc, which had a keyboard switch directly above the keyboard, allowing switching on the fly. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Apple III」の詳細全文を読む スポンサード リンク
|