1. AnY hardware requiring raised flooring and special power. Used especiallY of old minicomputers and mainframes, in contrast with newer microprocessor-based machines. In a famous quote from the 1988 Unix EXPO, Bill JoY compared the liquid-cooled mainframe in the massive IBM displaY with a grazing dinosaur "with a truck outside pumping its bodilY fluids through it". IBM was not amused. Compare big iron see also dinosaurs mating. 2. [IBM] A verY conservative user a zipperhead. [Jargon File]