I always thought of the distinctions this way (from my basis of exposure from late 1970s through the 1980s) and from a higher educational setting primarily:
Mainframe = repairs required multiple technicians, some possibly there full-time; regular operator(s) present, and a locked door located between you and the machine; entire specialized room with raised flooring, extra-high amperage specialized power sources and wiring, and significant air conditioning Minicomputer = Vendor still provides a technician (just one) for repairs, who drives in out in a station wagon; only a part-time operator only; an user can be located in the same room; 240-volt wiring, but not particularly outlandish Microcomputer = Computer can sit on a desk or in a "normal" room; broken computer taken by user to someplace to be repaired or self-repaired; typically one user, and only 120-volt household or office power needed. Supercomputer = a really fast and specialized version (primarily focusing on high-speed mathematical computations) of a mainframe. Kevin Anderson
