RCA 501 | 1958
The RCA 501 is a transistor computer manufactured by RCA starting in 1958. RCA's experience in developing transistors for other products provided the basis for introducing the RCA 501 in 1959, which was promoted as "the world's most advanced electronic data processing system." This computer was designed by industrial designer John Vassos, who used a modular design and color coding to enhance operational efficiency.
The United States Air Force purchased a 501 system in 1959 for $121,698, with other customers including the US Navy, Army, State Farm Life Insurance, and General Tire. A compatible version of this model was sold by English Electric as the KDP10/KDF8.
The RCA 501 utilized advanced manufacturing techniques such as pluggable card units and printed circuit boards, and it featured a centralized operating console for controlling all operations. It used high-speed magnetic-core memory, expandable from 16k to 260k characters, and an optional drum memory unit could provide up to 1.5 million characters of storage. Up to 63 magnetic tape units could be installed, using a variable length recording method. The computer weighed approximately 2,500 pounds (about 1.1 tons).

