A minicomputer, a term no longer much used, is a computer of a size intermediate between a microcomputer and a mainframe. Typically, minicomputers have been stand-alone computers (computer systems with attached terminals and other devices) sold to small and mid-size businesses for general business applications and to large enterprises for department-level operations. In recent years, the minicomputer has evolved into the "mid-range server" and is part of a network. IBM's AS/400e is a good example.
In an ascending hierarchy of general computer sizes, we find:
- The embedded systems programming computer, which is embedded in something and doesn't support direct human interaction but nevertheless meets all the other criteria of a microcomputer
- The microcomputer
- The workstation, as used to mean a more powerful personal computer for special applications
- The minicomputer
- The cluster, which is often several microcomputers or larger computers that share a workload and back each other up
- The mainframe or mainframe computer, which is now usually referred to by its manufacturers as a "large server"
- The supercomputer, formerly almost a synonym for "Cray supercomputer" but now meaning a very large server and sometimes including a system of computers using parallel processing
- The parallel processing system, which is a system of interconnected computers that work on the same application together, sharing tasks that can be performed concurrently