Fundamentals of Time Shared Computers

This document, from a 1968 issue of Computer Design, provides a foundational look at time-sharing in computer systems. It defines time-sharing as the simultaneous use of a computer by multiple users, covering general-purpose, real-time, and on-line systems. The article explores the underlying design criteria—flexibility, modularity, and open-endedness—and breaks down the system into its primary components: hardware, operating system software, and the user. Significant emphasis is placed on the hardware architecture, including the structure of processors, primary memory, peripheral/file memory, control units, and switching mechanisms. It also discusses memory allocation methods, hardware interrupts, and the specific advantages of time-shared systems, such as improved resource utilization, symbiotic problem-solving, and efficient user community collaboration.