1. In computer folklore, an ill-defined period from ENIAC (ca. 1943) to the mid-1950s; the great age of electromechanical dinosaurs. Sometimes used for the entire period up to 1960--61 (see Iron Age); however, it is funnier and more descriptive to characterize the latter period in terms of a ‘Bronze Age’ era of transistor-logic, pre-ferrite-core machines with drum or CRT mass storage (as opposed to just mercury delay lines and/or relays). See also Iron Age.
How things weren't in the Stone Age.
(The next cartoon in the Crunchly saga is 76-07-18. The previous cartoon was 76-03-14:5-8.)
2. More generally, a pejorative for any crufty, ancient piece of hardware or software technology. Note that this is used even by people who were there for the Stone Age (sense 1).