General-Purpose Mainframe and Minicomputer Era: (1959 to Present)
The introduction of the IBM 1401 and 7090 transistorized machines in 1959 marked the beginning of widespread commercial use of mainframe computer. The mainframe era was a period of highly centralized computing under the control of professional programmers and systems operators (usually in a corporate data center), with most elements of infrastructure provided by a single vendor, the manufacturer of the hardware and the software. This pattern began to change with the introduction of minicomputers produced by Digital Equipment Corporation (DEC) in 1965. In recent years, the minicomputer has evolved into a midrange computer or midrange server and is part of a network.