Artifact Details Title Johnniac Selectron Tube Catalog Number X281.83 Type Physical object Description One of the forty RCA Selectron tubes installed on the Rand Corporation Johnniac Computer in 1950. The tubes constituted the 256-word, 40-bit memory. In 1954 a 4000-word magnetic core memory replaced the tubes. Date 1953 Manufacturer Radio Corporation of America (RCA) Place Manufactured U.S. Identifying Numbers Model number Johnniac Serial number c7761A-T11 VT6827 Dimensions 3 x 9 x 3 in. Category Memory/electrostatic Subject mechanical; Electronic; Vacuum tube Credit Gift of Fred Gruenberger Lot Number X281.83
