Personal Computer | Research & Encyclopedia Articles

Personal Computer

The personal computer (abbreviated PC) is a computer that does not need to be connected to a larger computer in order to operate, and is capable of repetitively and efficiently performing calculations and instructions while being operated by an individual. It is smaller, less expensive, and easier to use than other types of computers such as minicomputers, mainframes, and supercomputers. The PC traces its ancestry to the mainframes and minicomputers of the 1950s and 1960s, which were all based on microprocessor technology that enabled manufacturers to place an entire central processing unit (CPU) on one semiconductor chip in order to perform all arithmetic, logic, and control functions.

In the 1960s, when microcomputers (they were not yet called personal computers) were evolving, they were distinguished from other computers by their size--they were smaller than minicomputers, which in turn were smaller than mainframes. While early mainframes needed the floor space of a house, minicomputers were the size of that home's refrigerator; microcomputers could fit on a desk inside that house. At that time the term microcomputer referred to any machine with the characteristics of being: (1) digital (rather than analog), (2) user programmable, (3) mostly automatic, (4) transportable, (5) sold either as a commercially manufactured product, an unassembled kit, or a published kit plan, and (6) did not require a programmer or technician to operate.

The following is a brief outline of microcomputer development, which eventually lead to the personal computer. Conceived in 1949 by Edmund Berkeley and built in 1950, the Simon was called a "mechanical brain." Although not considered the first personal computer, it did satisfy the microcomputer requirements mentioned above. Built in 1965, Digital Equipment Corporation's PDP-8 inspired Steven Gray to found the Amateur Computer Society (ACS) in 1966. The birth of the ACS is often thought to mark the dawn of personal computing. Even so, the PDP-8 is still not usually considered the first personal computer.

Up until the early 1970s most people thought of a computer only as a large, sluggish "number cruncher"; a mammoth device, contained in a glass-enclosed, climate-controlled room, that consumed vast amounts of electricity processing the data on punch cards, storing information on magnetic tape spools, and then printing the results on green-and-white-striped paper. Most people never imagined that a computer could be small enough to sit on a desk. But in 1969 Intel Corporation developed a CPU chip that could receive data and perform simple functions; by 1971 the chip had became a microprocessor, the first single-chip CPU that performed complex calculations. The Intel chip owed its existence to the miniaturization of integrated electronic circuits, which allowed computer manufacturers to increase computer performance and decrease expense. The Hewlett Packard HP 9830, introduced in 1972, was the first desktop "all-in-one" computer, but few people knew about it because HP marketed it exclusively to the scientific sector. The Xerox Alto, designed in 1973, was never commercially produced because Xerox's Palo Alto Research Center development team could not convince management of its usefulness. The Alto is often considered that era's most innovative design because it possessed a mouse, a point-and-click graphic user interface (GUI), an object-oriented operating system, and fast networking with the first ethernet cards.

None of the largest computer corporations of that time would introduce the world to the modern PC. Those behemoths did not see financial value in manufacturing an inexpensive product that might replace the mainframes that they were successfully selling. Fortunately, idealistic individuals succeeded where corporate leaders failed, eventually introducing the first personal computer.

In 1975 Micro Instrumentation and Telemetry Systems (MITS) introduced the Altair 8800, enabling hobbyists to assemble their own computers. It had no monitor, no keyboard, no printer, and couldn't store data, but it created enormous demand. Although not the first available microcomputer, it is often considered the computer that began the personal computer industry. MITS went out of business, but its existence helped two young software programmers, Bill Gates and Paul Allen (whose version of BASIC was used for the Altair), in the creation of Microsoft Corporation.

In 1977 American entrepreneur Steven Jobs and computer designer Stephen Wozniak created the Apple II, a fairly inexpensive computer with a keyboard, monitor, and modem. It was the first personal computer mass-produced and pre-assembled in a factory and the first capable of color graphics. Apple Computer incorporated the Visicalc spreadsheet program on the Apple II, enabling users for the first time to change one number and watch the effect it had on the entire budget. This combination made the Apple II a standard business device, and today it is considered the first "true" personal computer, largely because it proved that computers were more than just "expensive calculators."

Even with all of the successes of the early PC manufacturers, the PC was not seen as a serious business tool until, in 1981, International Business Machines (IBM) introduced the IBM PC. It was the first computer to stamp "personal computer" on its name and is often called "the computer that launched an industry." The IBM PC was designed with an open architecture, meaning that other manufacturers could create similar machines, or clones, that would also run IBM PC-designed software. The IBM PC and its clones soon became the PC standard. Because old-time mainframe computer maker IBM sold this product, the PC became a legitimate business tool. The Apple Lisa (1982) and Macintosh (1984) featured the first graphical user interface (GUI), which enabled a "point-and-click" mouse to select commands, point to icons, call up files, start programs, and perform other routine tasks; this eliminated the need to memorize the often arcane and complex commands required by the IBM PC's operating system, DOS.

Today PCs generally consist of (1) a microprocessor, the CPU that directs logical and arithmetical functions and runs computer programs through electronic circuits; (2) memory to temporarily store programs and data, and mass storage devices (such as hard-, floppy-, and CD-ROM drives) to permanently store information; (3) a keyboard and mouse; 4) a video monitor; (5) a printer; (6) a sound-adapter and speakers; and (7) a modem to connect to the Internet. But its parts do not define the personal computer because many of these same components are common across the spectrum of computers, from calculators to supercomputers.