A
microcomputer is a small, relatively inexpensive
computer having a
central processing unit (CPU) made out of a
microprocessor.
[2] The computer also includes
memory and
input/output (I/O) circuitry together mounted on a
printed circuit board (PCB).
[3] Microcomputers became popular in the 1970s and 1980s with the advent of increasingly powerful microprocessors. The predecessors to these computers,
mainframes and
minicomputers, were comparatively much larger and more expensive (though indeed present-day mainframes such as the
IBM System z machines use one or more custom microprocessors as their CPUs). Many microcomputers (when equipped with a
keyboard and
screen for input and output) are also
personal computers (in the generic sense). An early use of the term "personal computer" in 1962 predates microprocessor-based designs.
(See "Personal Computer: Computers at Companies" reference below). A "microcomputer" used as an embedded control system may have no human-readable input and output devices. "Personal computer" may be used generically or may denote an
IBM PC compatible machine.