In the broadest sense, any large computer—large in the sense of computing capacity, that is, not in physical size--can be classified as a "mainframe" computer. Other classes of computer include supercomputers, minicomputers, and personal computers. Although there is no precise formula for what differentiates a mainframe computer from other types, there are some basic guidelines. Generally speaking, in a multi-user environment a mainframe computer is capable of supporting more users than a minicomputer. Like the typical mainframe computer, a supercomputer is a large and powerful device but, unlike the more general-purpose mainframe, usually serves a few users or only one, and is usually dedicated to solving complex computational problems (such as those found in advanced engineering or scientific applications), rather than to general-purpose use.

The term "mainframe computer" had its genesis in the early days of the commercial computer industry. The major components of the electronic...