The tale is from the early 1950s, when Bob was one of several scientists who wrote programs for a unique computer at ORNL called ORACLE, or Oak Ridge Automatic Computer and Logical Engine. Like other
computers of that era, it had enough vacuum tubes to fill a room. It also had a couple dozen cathode-ray tubes for its memory. Each CRT could store 1,024 binary digits (bits) of electrostatic memory in the form of a 32-by-32 array of charged dots spaced a fraction of an inch apart on the tube’s flat face.
This type of memory was vulnerable to being electrically damaged if the same dot was rewritten with the same value (0 or 1) too frequently. Typically, this would happen if a program accidentally went into a tight loop. So the operators had to constantly listen to a loudspeaker that was connected to the computer’s circuits, ready to hit the kill switch if the varying tones suddenly turned into a high-pitched whine.