A minicomputer, or colloquially mini, is a type of smaller general-purpose computer developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, The New York Times suggested a consensus definition of a minicomputer as a machine costing less than US$25,000, with an input-output device such as a teleprinter and at least four thousand words of memory, that is capable of running programs in a higher level language, such as Fortran or BASIC.
Six different minicomputers (out of many more models) produced by the Digital Equipment Corporation (DEC) with the year of introduction in brackets: First row: PDP-1 (1959), PDP-7 (1964), PDP-8 (1965); second row: PDP-8/E (1970), PDP-11/70 (1975), PDP-15 (1970).
Data General Nova, serial number 1, on display at the Computer History Museum
Raytheon RDS 500 seismic processing system in Benghazi in 1978
Varian Data Machines system connected to analogue tape playback system in 1984
A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise resource planning, and large-scale transaction processing. A mainframe computer is large but not as large as a supercomputer 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.
A single-frame IBM z15 mainframe. Larger capacity models can have up to four total frames. This model has blue accents, as compared with the LinuxONE III model with orange highlights.
A pair of IBM mainframes. On the left is the IBM z Systems z13. On the right is the IBM LinuxONE Rockhopper.
An IBM System z9 mainframe
Inside an IBM System z9 mainframe