A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications, bulk data processing (such as the census and industry and consumer statistics, enterprise resource planning, and large-scale transaction processing). A mainframe computer is larger and has more processing power than some other classes of computers, such as minicomputers, servers, workstations, and personal computers. Most large-scale computer-system architectures were established in the 1960s, but they continue to evolve. Mainframe computers are often used as servers.
The term mainframe derived from the large cabinet, called a main frame, that houses the central processing unit and main memory of early computers.[full citation needed] Later, the term mainframe was used to distinguish high-end commercial computers from less powerful machines.