power. Used especially of old minis 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 mainframe. 2. [IBM] A very conservative user; a zipperhead.