Many of the first practical nonhuman computers were analog machines, most famously the mechanical Differential Analyzer built by Vannevar Bush in 1931. Even after digital computers arrived, analog computers remained popular into the 1970s, especially for simulations (they were used to drive flight simulators for the X-15 [pdf] rocket plane and early spacecraft). And innovation continued well beyond the Differential Analyzer’s wheels and cogs. As advertised in March 1964, this PACE TR-48 analog computer was not only “fully transistorized” but also mobile—once you put it on its stand and pushed it to another electrical outlet.
Part of a continuing series looking the story of technology as told through advertisements.
This article originally appeared in print as “The Apex of Analog.”