Iron Age: n.

In the history of computing, 1961-1971 — the formative era of commercial mainframe technology, when ferrite-core dinosaurs ruled the earth. The Iron Age began, ironically enough, with the delivery of the first minicomputer (the PDP-1) and ended with the introduction of the first commercial microprocessor (the Intel 4004) in 1971. See also Stone Age; compare elder days.