Mainframe was a term originally referring to the cabinet containing the central
processor unit or "main frame" of a room-filling stone age batch machine. after the
emergence of smaller "minicomputer" designs in the early 1970s, the traditional big
iron machines were described as "mainframe computers" and eventually just as
mainframes. nowadays a mainframe is a very large and expensive computer capable of
supporting hundreds, or even thousands, of users simultaneously. the chief difference
between a supercomputer and a mainframe is that a supercomputer channels all its
power into executing a few programs as fast as possible, whereas a mainframe uses its
power to execute many programs concurrently. in some ways, mainframes are more
powerful than supercomputers because they support more simultaneous programs. but
supercomputers can execute a single program faster than a mainframe. the distinction
between small mainframes and minicomputers is vague, depending really on how the
manufacturer wants to market its machines.