Sytematization of Tube Surveillance in Large-Scale Computers

Operation of the ENIAC (electronic numerical integrator and calculator), a high-speed electronic computing machine, at the Ballistic Research Laboratories of Aberdeen Proving Ground, has shown that 90 per cent of the service interruptions are caused by vacuum-tube failures. At the beginning of 1950 a tube surveillance program was initiated in which all pertinent data concerning each tube in the system are recorded on punched cards. This paper describes the manner in which faulty vacuum tubes are detected and replaced, and gives the specifications used in testing the tubes and the manner in which the tube history is gathered. Preliminary results, using data collected during the first five months of 1950, are given.