A computer operating system spans multiple layers of complexity, from commands entered at a keyboard to the details of electronic switching. In addition, the system is organized as a hierarchy of abstractions. Various parts of such a system and system dynamics (using the Unix operating system as an example) are described. (JN)

This familiar card game has interested mathematicians, economists, and psychologists as a model of decision-making in the real world. It is now serving as a vehicle for investigations in computer science. (Author/MA)

Speech recognition by computers is discussed, including methods of recognizing isolated words and procedures for analyzing connected speech. Describes Bell Laboratories' speech recognition system which attempts to combine major elements of human communication into a single operating unit. (DS)