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A personal computer is a general-purpose computer whose size, capabilities and original sale price make it useful for individuals, and is intended to be operated directly by an end-user with no intervening computer operator. This contrasts with the batch processing or time-sharing models that allowed larger, more expensive minicomputer and mainframe systems to be used by many people, usually at the same time. A related term is "PC" that was initially an abbreviation for "personal computer", but later became used primarily to refer to the ubiquitous Wintel platform. Software applications for most personal computers include, but are not limited to, word processing, spreadsheets, databases, web browsers and e-mail clients, digital media playback, games and many personal productivity and special-purpose software applications. Modern personal computers often have connections to the Internet, allowing access to the World Wide Web and a wide range of other resources. Personal computers may be connected to a local area network (LAN), either by a cable or a wireless connection. A personal computer may be a laptop computer or a desktop computer running an operating system such as Windows, Linux (and it's various operating systems based on it), or Macintosh OSX. Early computer owners usually had to write their own programs to do anything useful with the machines, which even did not include an operating system. The very earliest microcomputers, equipped with a front panel, required hand-loading of a bootstrap program to load programs from external storage (paper tape, cassettes, or eventually diskettes). Before very long, automatic booting from permanent read-only memory became universal. Today's users have access to a wide range of commercial software, freeware and free and open-source software, which are provided in ready-to-run or ready-to-compile form. Software for personal computers, such as applications and video games, are typically developed and distributed independently from the hardware or OS manufacturers, whereas software for many mobile phones and other portable systems is approved and distributed through a centralized online store. Since the early 1990s, Microsoft operating systems and Intel hardware have dominated much of the personal computer market, first with MS-DOS and then with Windows. Popular alternatives to Microsoft's Windows operating systems include Apple's OS X and free open-source Unix-like operating systems such as Linux and BSD. AMD provides the major alternative to Intel's processors. == History == The Programma 101 was the first commercial "desktop personal computer", produced by the Italian company Olivetti and invented by the Italian engineer Pier Giorgio Perotto, inventor of the magnetic card system. The project started in 1962. It was launched at the 1964 New York World's Fair, and volume production began in 1965, the computer retailing for $3,200.〔(【引用サイトリンク】url=http://royal.pingdom.com/2012/08/28/the-first-pc-from-1965/ )〕 NASA bought at least ten Programma 101s and used them for the calculations for the 1969 Apollo 11 Moon landing. Then ABC used the Programma 101 to predict the presidential election of 1969, and the U.S. military used the machine to plan their operations in the Vietnam War. The Programma 101 was also used in schools, hospitals, government offices. This marked the beginning of the era of the personal computer. In 1968, Hewlett-Packard was ordered to pay about $900,000 in royalties to Olivetti after their Hewlett-Packard 9100A was ruled to have copied some of the solutions adopted in the Programma 101, including the magnetic card, the architecture and other similar components.〔 The Soviet MIR series of computers was developed from 1965 to 1969 in a group headed by Victor Glushkov. It was designed as a relatively small-scale computer for use in engineering and scientific applications and contained a hardware implementation of a high-level programming language. Another innovative feature for that time was the user interface combining a keyboard with a monitor and light pen for correcting texts and drawing on screen. In what was later to be called the Mother of All Demos, SRI researcher Douglas Engelbart in 1968 gave a preview of what would become the staples of daily working life in the 21st century: e-mail, hypertext, word processing, video conferencing and the mouse. The demonstration required technical support staff and a mainframe time-sharing computer that were far too costly for individual business use at the time. By the early 1970s, people in academic or research institutions had the opportunity for single-person use of a computer system in interactive mode for extended durations, although these systems would still have been too expensive to be owned by a single person. In 1973 the IBM Los Gatos Scientific Center developed a portable computer prototype called SCAMP (Special Computer APL Machine Portable) based on the IBM PALM processor with a Philips compact cassette drive, small CRT and full function keyboard. SCAMP emulated an IBM 1130 minicomputer in order to run APL\1130.〔(IBM Archives )〕 In 1973 APL was generally available only on mainframe computers, and most desktop sized microcomputers such as the Wang 2200 or HP 9800 offered only BASIC. Because SCAMP was the first to emulate APL\1130 performance on a portable, single user computer, ''PC Magazine'' in 1983 designated SCAMP a "revolutionary concept" and "the world's first personal computer".〔〔''PC Magazine'', Vol. 2, No. 6, November 1983, ‘’SCAMP: The Missing Link in the PC's Past?‘’〕 This seminal, single user portable computer now resides in the Smithsonian Institution, Washington, D.C.. Successful demonstrations of the 1973 SCAMP prototype led to the IBM 5100 portable microcomputer launched in 1975 with the ability to be programmed in both APL and BASIC for engineers, analysts, statisticians and other business problem-solvers. In the late 1960s such a machine would have been nearly as large as two desks and would have weighed about half a ton.〔 Another seminal product in 1973 was the Xerox Alto, developed at Xerox's Palo Alto Research Center (PARC), it had a graphical user interface (GUI) which later served as inspiration for Apple Computer's Macintosh, and Microsoft's Windows operating system. Also in 1973 Hewlett Packard introduced fully BASIC programmable microcomputers that fit entirely on top of a desk, including a keyboard, a small one-line display and printer. The Wang 2200 microcomputer of 1973 had a full-size cathode ray tube (CRT) and cassette tape storage. These were generally expensive specialized computers sold for business or scientific uses. The introduction of the microprocessor, a single chip with all the circuitry that formerly occupied large cabinets, led to the proliferation of personal computers after 1975. Early personal computersgenerally called microcomputerswere often sold in a kit form and in limited volumes, and were of interest mostly to hobbyists and technicians. Minimal programming was done with toggle switches to enter instructions, and output was provided by front panel lamps. Practical use required adding peripherals such as keyboards, computer displays, disk drives, and printers. Micral N was the earliest commercial, non-kit microcomputer based on a microprocessor, the Intel 8008. It was built starting in 1972 and about 90,000 units were sold. In 1976 Steve Jobs and Steve Wozniak sold the Apple I computer circuit board, which was fully prepared and contained about 30 chips. The Apple I computer differed from the other hobby computers of the time at the beckoning of Paul Terrell owner of the Byte Shop who gave Steve Jobs his first purchase order for 50 Apple I computers only if the computers were assembled and tested and not a kit computer so he would have computers to sell to everyone, not just people that could assemble a computer kit. The Apple I as delivered was still a kit computer as it did not have a power supply, case, or keyboard as delivered to the Byte Shop. The first successfully mass marketed personal computer was the Commodore PET introduced in January 1977, but back-ordered and not available until later in the year.〔 Commodore press release. "The PET computer made its debut recently as the first 100 units were shipped to waiting customers in mid-October 1977."〕 At the same time, the Apple II (usually referred to as the "Apple") was introduced〔(【引用サイトリンク】url=http://apple2history.org/history/ah02/#03 )〕 (June 1977), and the TRS-80 from Tandy Corporation / Tandy Radio Shack in summer 1977, delivered in September in a small number. Mass-market ready-assembled computers allowed a wider range of people to use computers, focusing more on software applications and less on development of the processor hardware. During the early 1980s, home computers were further developed for household use, with software for personal productivity, programming and games. They typically could be used with a television already in the home as the computer display, with low-detail blocky graphics and a limited color range, and text about 40 characters wide by 25 characters tall. Sinclair Research,〔(【引用サイトリンク】title=Sinclair Research website )〕 a UK company, produced the ZX Series - the ZX80 (1980), ZX81 (1981), and the ZX Spectrum; the latter was introduced in 1982, and totaled 8 million unit sold. Following came the Commodore 64, totaled 17 million units sold. In the same year, the NEC PC-98 was introduced, which was a very popular personal computer that sold in more than 18 million units. Another famous personal computer, the revolutionary Amiga 1000, was unveiled by Commodore on July 23, 1985. The Amiga 1000 featured a multitasking, windowing operating system, color graphics with a 4096-color palette, stereo sound, Motorola 68000 CPU, 256 kB RAM, and 880 kB 3.5-inch disk drive, for US$1,295. Somewhat larger and more expensive systems (for example, running CP/M), or sometimes a home computer with additional interfaces and devices, although still low-cost compared with minicomputers and mainframes, were aimed at office and small business use, typically using "high resolution" monitors capable of at least 80 column text display, and often no graphical or color drawing capability. Workstations were characterized by high-performance processors and graphics displays, with large-capacity local disk storage, networking capability, and running under a multitasking operating system. Eventually, due to the influence of the IBM PC on the personal computer market, personal computers and home computers lost any technical distinction. Business computers acquired color graphics capability and sound, and home computers and game systems users used the same processors and operating systems as office workers. Mass-market computers had graphics capabilities and memory comparable to dedicated workstations of a few years before. Even local area networking, originally a way to allow business computers to share expensive mass storage and peripherals, became a standard feature of personal computers used at home. In 1982 "The Computer" was named Machine of the Year by ''Time'' Magazine. In the 2010s, several companies such as Hewlett-Packard and Sony sold off their PC and laptop divisions. As a result, the personal computer was declared dead several times during this time. 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「Personal computer」の詳細全文を読む スポンサード リンク
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