The Nucleus of a Multiprogramming System This paper describes the philosophy and structure of a multiprogramming system that can be extended with a hierarchy of operating systems to suit diverse requirements of program scheduling and resource allocation. The system nucleus simulates an environment in which program execution and input/output are handled uniformly as parallel, cooperating process es. A fundamental set of primitives allows the dynamic creation and control of a hierarchy of processes as well as the communication among them. CACM April, 1970 Hansen, P. B. multiprogramming, operating systems, parallel processes, process concept, process communication, message buffering, process hierarchy, process creation, process removal 4.30 4.31 4.32 4.41 CA700404 JB February 13, 1978 3:10 PM 1657 4 2080 2080 4 2080 2357 4 2080 2536 4 2080 1523 5 2080 2080 5 2080 2080 5 2080 2080 5 2080 2319 5 2080 2320 5 2080 2378 5 2080 2632 5 2080 2738 5 2080 2740 5 2080 2868 5 2080 3127 5 2080 1408 6 2080 1471 6 2080 1471 6 2080 1719 6 2080 1749 6 2080 1749 6 2080 1749 6 2080 1749 6 2080 1751 6 2080 1877 6 2080 2016 6 2080 2017 6 2080 2080 6 2080 2080 6 2080 2080 6 2080 2080 6 2080 2080 6 2080 2080 6 2080 2080 6 2080 2080 6 2080 2150 6 2080 2188 6 2080 2203 6 2080 2204 6 2080 2247 6 2080 2277 6 2080 2356 6 2080 2377 6 2080 2380 6 2080 2558 6 2080 2625 6 2080 2632 6 2080 2777 6 2080