any of a class of small digital computers whose central processing unit (CPU) is contained on a single integrated semiconductor chip. A microcomputer uses a single microprocessor for its CPU, which performs all logic and arithmetic operations. The system also contains a number of associated semiconductor chips that serve as the main memory for storing program instructions and data and as interfaces for exchanging data of this sort with peripheral equipment--namely, input/output devices (e.g., keyboard, video display, and printer) and auxilliary storage units. Smaller microcomputers first marketed in the 1970s contain a single chip on which all CPU, memory, and interface circuits are integrated.

As large-scale integration and then very-large-scale integration have progressively increased the number of transistors that can be placed on one semiconductor chip, so the processing capacity of microcomputers using such single chips has grown commensurately. During the 1980s microcomputers came to be used widely in other applications besides video games and other relatively simple computer-based recreations. Increasingly powerful microcomputers began to be used in personal computer systems and workstations, for instance. High-performance microcomputer systems are used widely in business, in engineering, in "smart" or intelligent machines employed in the factory and office, and in military electronics systems.

In the early 1990s, small computers that fit in a pocket yet provide the power of a desktop personal computer were introduced. These pocket, or palm-sized, computers are distinguished by their high portability, enhanced performance, and low cost.