engine , Harvard Mark I , Z3 Second Generation (Vacuum Tubes) Calculators Atanasoff–Berry Computer , IBM 604 , UNIVAC 60 , UNIVAC 120 Programmable Devices Colossus , ENIAC , Manchester Small-Scale Experimental Machine , EDSAC , Manchester Mark 1 , Ferranti Pegasus , Ferranti Mercury , CSIRAC , EDVAC , UNIVAC