The Science Of Computers

Modern digital computers are all conceptually similar, regardless of size. Nevertheless, they can be divided into several categories on the basis of cost and performance: the personal computer or microcomputer, a relatively low-cost machine, usually of desk-top size (though "laptops" are small enough to fit in a briefcase, and "palmtops" can fit into a pocket); the workstation, a microcomputer with enhanced graphics and communications capabilities that make it especially useful for office work; the minicomputer, generally too expensive for personal use, with capabilities suited to a business
, school, or laboratory; and the mainframe computer, a large, expensive machine with the capability of serving the needs of major business enterprises, government departments, scientific research establishments, or the like (the largest and fastest of these are called supercomputers).