Wikipedia
BIZMAC
The RCA BIZMAC was a vacuum tube computer manufactured by RCA from 1956 to 1962. Although RCA was noted for their pioneering work in transistors, RCA decided to build a vacuum computer instead of a transistorized computer. It was the largest vacuum tube computer of its time in 1956, occupying 20,000 square feet of floor space with up to 30,000 tubes, 70,000 diodes, and 35,000 magnetic cores.