Personal computer

Source: Wikipedia, the free encyclopedia.

A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use.[1] Personal computers are intended to be operated directly by an end user, rather than by a computer expert or technician. Unlike large, costly minicomputers and mainframes, time-sharing by many people at the same time is not used with personal computers. Primarily in the late 1970s and 1980s, the term home computer was also used.

Institutional or corporate computer owners in the 1960s had to write their own programs to do any useful work with the machines. While personal computer users may develop their own applications, usually these systems run commercial software, free-of-charge software ("freeware"), which is most often proprietary, or free and open-source software, which is provided in "ready-to-run", or binary, form. Software for personal computers is typically developed and distributed independently from the hardware or operating system manufacturers.[2] Many personal computer users no longer need to write their own programs to make any use of a personal computer, although end-user programming is still feasible. This contrasts with mobile systems, where software is often available only through a manufacturer-supported channel,[3] and end-user program development may be discouraged by lack of support by the manufacturer.[4]

Since the early 1990s, Microsoft operating systems and Intel hardware dominated much of the personal computer market, first with MS-DOS and then with Windows. Alternatives to Microsoft's Windows operating systems occupy a minority share of the industry. These include Apple's macOS and free and open-source Unix-like operating systems, such as Linux.

The advent of personal computers and the concurrent Digital Revolution have significantly affected the lives of people in all countries.

Terminology

The term "PC" is an

initialism for "personal computer". While the IBM Personal Computer
incorporated the designation in its model name, the term originally described personal computers of any brand.

In some contexts, "PC" is used to contrast with "Mac", an Apple Macintosh computer.[5][6][7][8] Since none of these Apple products were mainframes or time-sharing systems, they were all "personal computers" and not "PC" (brand) computers.

In 1995, a CBS segment on the growing popularity of PC reported "For many newcomers PC stands for Pain and Confusion".[9]

History

The 8-bit architecture Pravetz 82 computer produced in Bulgaria from 1982, in school class in the Soviet Union

The "brain" [computer] may one day come down to our level [of the common people] and help with our income-tax and book-keeping calculations. But this is speculation and there is no sign of it so far.

— British newspaper The Star in a June 1949 news article about the EDSAC computer, long before the era of the personal computers.[10]

In the

Bendix G15 and LGP-30 of 1956, and the Soviet MIR series of computers developed from 1965 to 1969.[citation needed] 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.

The personal computer was made possible by major advances in

silicon-gate MOS integrated circuit was developed by Federico Faggin at Fairchild in 1968.[15] Faggin later used silicon-gate MOS technology to develop the first single-chip microprocessor, the Intel 4004, in 1971.[16] The first microcomputers
, based on microprocessors, were developed during the early 1970s. Widespread commercial availability of microprocessors, from the mid-1970s onwards, made computers cheap enough for small businesses and individuals to own.

In what was later to be called

. The demonstration required technical support staff and a mainframe time-sharing computer that were far too costly for individual business use at the time.

Early personal computers‍—‌generally called microcomputers‍—‌were often sold in a

.

IBM PC and its descendants.[18]

In 1973, the

PC Magazine in 1983 designated SCAMP a "revolutionary concept" and "the world's first personal computer".[19][20] 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.[19]

Another desktop portable APL machine, the MCM/70, was demonstrated in 1973 and shipped in 1974. It used the Intel 8008 processor.

A seminal step in personal computing was the 1973

Windows operating system. The Alto was a demonstration project, not commercialized, as the parts were too expensive to be affordable.[21]

Also in 1973

cathode ray tube (CRT) and cassette tape storage.[22]
These were generally expensive specialized computers sold for business or scientific uses.

1974 saw the introduction of what is considered by many to be the first true "personal computer", the

computer bus designed for the Altair was to become a de facto standard in the form of the S-100 bus, and the first programming language for the machine was Microsoft's founding product, Altair BASIC.[28][29]

In 1976,

Byte Shop, Jobs and Wozniak were given their first purchase order, for 50 Apple I computers, only if the computers were assembled and tested and not a kit computer. Terrell wanted to have computers to sell to a wide range of users, not just experienced electronics hobbyists who had the soldering skills to assemble a computer kit. The Apple I
as delivered was still technically a kit computer, as it did not have a power supply, case, or keyboard when it was delivered to the Byte Shop.

The first successfully mass-marketed personal computer to be announced was the

Tandy Radio Shack
following in August 1977, which sold over 100,000 units during its lifetime. Together, these 3 machines were referred to as the "1977 trinity". Mass-market, ready-assembled computers had arrived, and allowed a wider range of people to use computers, focusing more on software applications and less on development of the processor hardware.

In 1977 the Heath company introduced personal computer kits known as Heathkits, starting with the Heathkit H8, followed by the Heathkit H89 in late 1979. With the purchase of the Heathkit H8 you would obtain the chassis and CPU card to assemble yourself, additional hardware such as the H8-1 memory board that contained 4k of RAM could also be purchased in order to run software. The Heathkit H11 model was released in 1978 and was one of the first 16-bit personal computers; however, due to its high retail cost of $1,295 was discontinued in 1982.[32][33][34]

IBM 5150
, released in 1981
The 8-bit PMD 85 personal computer produced in 1985–1990 by the Tesla company in the former Socialist Czechoslovakia

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,[35] 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[36][37] and the Amstrad CPC series (464–6128).

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.[38] Another famous personal computer, the revolutionary Amiga 1000, was unveiled by Commodore on 23 July 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.[39]

IBM's first PC was introduced on 12 August 1981 setting what became a mass market standard for PC architecture.[40]

In 1982 "The Computer" was named Machine of the Year by Time magazine.[41]

Somewhat larger and more expensive systems were aimed at office and small business use. These often featured 80-column text displays but might not have had graphics or sound capabilities. These microprocessor-based systems were still less costly than time-shared mainframes or minicomputers.

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.

An increasingly important set of uses for personal computers relied on the ability of the computer to communicate with other computer systems, allowing interchange of information. Experimental public access to a shared mainframe computer system was demonstrated as early as 1973 in the Community Memory project, but bulletin board systems and online service providers became more commonly available after 1978. Commercial Internet service providers emerged in the late 1980s, giving public access to the rapidly growing network.

In 1991, the World Wide Web was made available for public use. The combination of powerful personal computers with high-resolution graphics and sound, with the infrastructure provided by the Internet, and the standardization of access methods of the Web browsers, established the foundation for a significant fraction of modern life, from bus time tables through unlimited distribution of free videos through to online user-edited encyclopedias.

Types

Stationary

Workstation

RISC processor

A workstation is a high-end personal computer designed for technical, mathematical, or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems. Workstations are used for tasks such as computer-aided design, drafting and modeling, computation-intensive scientific and engineering calculations, image processing, architectural modeling, and computer graphics for animation and motion picture visual effects.[42]

Desktop computer

Before the widespread use of PCs, a computer that could fit on a

LCD monitors
.

While the term "desktop" often refers to a computer with a vertically aligned computer

tower case, these varieties often rest on the ground or underneath desks. Despite this seeming contradiction, the term "desktop" does typically refer to these vertical tower cases as well as the horizontally aligned models which are designed to literally rest on top of desks and are therefore more appropriate to the "desktop" term, although both types qualify for this "desktop" label in most practical situations aside from certain physical arrangement differences. Both styles of these computer cases hold the systems hardware components such as the motherboard, processor chip and other internal operating parts. Desktop computers have an external monitor with a display screen and an external keyboard, which are plugged into ports on the back of the computer case. Desktop computers are popular for home and business computing applications as they leave space on the desk for multiple monitors
.

A

video card, processor and RAM, to improve the speed and responsiveness of demanding video games.[43]

An

all-in-one computer (also known as single-unit PCs) is a desktop computer that combines the monitor and processor within a single unit. A separate keyboard and mouse are standard input devices, with some monitors including touchscreen
capability. The processor and other working components are typically reduced in size relative to standard desktops, located behind the monitor, and configured similarly to laptops.

A nettop computer was introduced by Intel in February 2008, characterized by low cost and lean functionality. These were intended to be used with an Internet connection to run Web browsers and Internet applications.

A

computer display, and is often used as a digital photo viewer, music and video player, TV receiver, and digital video recorder. HTPCs are also referred to as media center systems or media servers. The goal is to combine many or all components of a home theater
setup into one box. HTPCs can also connect to services providing on-demand movies and TV shows. HTPCs can be purchased pre-configured with the required hardware and software needed to add television programming to the PC, or can be assembled from components.

Keyboard computers are computers inside of keyboards, generally still designed to be connected to an external computer monitor or television. Examples include the Atari ST, Amstrad CPC, BBC Micro, Commodore 64, MSX, Raspberry Pi 400, and the ZX Spectrum.

Portable

A portable computer Cambridge Z88
released in 1987

The potential utility of portable computers was apparent early on. Alan Kay described the Dynabook in 1972, but no hardware was developed. The Xerox NoteTaker was produced in a very small experimental batch around 1978. In 1975, the IBM 5100 could be fit into a transport case, making it a portable computer, but it weighed about 50 pounds.

Before the introduction of the IBM PC, portable computers consisting of a processor, display, disk drives and keyboard, in a suit-case style portable housing, allowed users to bring a computer home from the office or to take notes at a classroom. Examples include the Osborne 1 and Kaypro; and the Commodore SX-64. These machines were AC-powered and included a small CRT display screen. The form factor was intended to allow these systems to be taken on board an airplane as carry-on baggage, though their high power demand meant that they could not be used in flight. The integrated CRT display made for a relatively heavy package, but these machines were more portable than their contemporary desktop equals. Some models had standard or optional connections to drive an external video monitor, allowing a larger screen or use with video projectors.

IBM PC-compatible suitcase format computers became available soon after the introduction of the PC, with the

hard drive
to give roughly equivalent performance to contemporary desktop computers.

The development of thin plasma display and LCD screens permitted a somewhat smaller form factor, called the "lunchbox" computer. The screen formed one side of the enclosure, with a detachable keyboard and one or two half-height floppy disk drives, mounted facing the ends of the computer. Some variations included a battery, allowing operation away from AC outlets.[44]

Notebook computers such as the TRS-80 Model 100 and Epson HX-20 had roughly the plan dimensions of a sheet of typing paper (ANSI A or ISO A4). These machines had a keyboard with slightly reduced dimensions compared to a desktop system, and a fixed LCD display screen coplanar with the keyboard. These displays were usually small, with 8 to 16 lines of text, sometimes only 40 columns line length. However, these machines could operate for extended times on disposable or rechargeable batteries. Although they did not usually include internal disk drives, this form factor often included a modem for telephone communication and often had provisions for external cassette or disk storage. Later, clam-shell format laptop computers with similar small plan dimensions were also called "notebooks".

Laptop

A

battery, enhancing their portability. To save power, weight and space, laptop graphics chips are in many cases integrated into the CPU or chipset and use system RAM, resulting in reduced graphics performance when compared to desktop machines, that more typically have a graphics card installed. For this reason, desktop computers are usually preferred over laptops for gaming
purposes.

Unlike desktop computers, only minor internal upgrades (such as memory and hard disk drive) are feasible owing to the limited space and power available. Laptops have the same input and output ports as desktops, for connecting to external displays, mice, cameras, storage devices and keyboards. Laptops are also a little more expensive compared to desktops, as the miniaturized components for laptops themselves are expensive.

A desktop replacement computer is a portable computer that provides the full capabilities of a desktop computer. Such computers are currently large laptops. This class of computers usually includes more powerful components and a larger display than generally found in smaller portable computers, and may have limited battery capacity or no battery.[45]

Netbooks, also called mini notebooks or subnotebooks, were a subgroup of laptops[46][47] suited for general computing tasks and accessing web-based applications. Initially, the primary defining characteristic of netbooks was the lack of an optical disc drive, smaller size, and lower performance than full-size laptops. By mid-2009 netbooks had been offered to users "free of charge", with an extended service contract purchase of a cellular data plan.[48] Ultrabooks and Chromebooks have since filled the gap left by Netbooks. Unlike the generic Netbook name, Ultrabook and Chromebook are technically both specifications by Intel and Google respectively.

Tablet

A tablet uses a touchscreen display, which can be controlled using either a stylus pen or finger. Some tablets may use a "hybrid" or "convertible" design, offering a keyboard that can either be removed as an attachment, or a screen that can be rotated and folded directly over top the keyboard. Some tablets may use desktop-PC operating system such as Windows or Linux, or may run an operating system designed primarily for tablets. Many tablet computers have USB ports, to which a keyboard or mouse can be connected.

Smartphone

Smartphones are often similar to tablet computers, the difference being that smartphones always have cellular integration. They are generally smaller than tablets, and may not have a slate form factor.

Ultra-mobile PC

The ultra-mobile PC (UMP) is a small

VIA C7-M
processors.

Pocket PC

A pocket PC is a hardware specification for a handheld-sized computer (

RFID
readers and cameras.

In 2007, with the release of Windows Mobile 6, Microsoft dropped the name Pocket PC in favor of a new naming scheme: devices without an integrated phone are called Windows Mobile Classic instead of Pocket PC, while devices with an integrated phone and a touch screen are called Windows Mobile Professional.[49]

Palmtop and handheld computers

Windows CE
operating system.

Hardware

Printer