Mainframe

A mainframe is a term originally referring to the cabinet containing the central processing unit or "main frame" of room-filling computers.

History
After the emergence of smaller "minicomputer" designs in the 1960s and 70s, the traditional "big iron" machines were described as "mainframe computers" and eventually just as "mainframes". The term carries the connotation of a machine designed for batch rather than interactive use, though possibly with an interactive operating system retrofitted onto it; it is especially used of machines built by IBM,  and other major players in early or computing.

It has been common wisdom among hackers since the late 1980s that the mainframe architectural tradition is essentially dead (outside of the tiny market for number-crunching supercomputers such as ), having been swamped by the recent huge advances in integrated circuit technology and low-cost personal computing. As of 1993, corporate America was beginning to figure this out with a wave of failures, takeovers, and mergers among traditional mainframe makers.

Supporters claim that mainframes still house 90% of the data that major businesses rely on for mission-critical applications, attributing this to their superior performance, reliability, scalability, and security in comparison to microprocessors. Modern mainframes are often composed of smaller servers that are networked together for redundancy at data centers set up for cloud computing.