Mainframe computers are data processing systems employed in mainly in large organizations for various applications Reference n/mainframe-computer.html n/mainframe-computer.html
Minicomputers have been stand-alone computers (computer systems with attached terminals and other devices) Reference minicomputer minicomputer
Microcomputers are "Microcomputer" is an antiquated term that refers to a computer that uses a microprocessor (integrated circuit) for its Central Processing Unit Reference microcomputers.htm microcomputers.htm