Multiprogramming and Time Sharing

History of multiprogramming and time sharing

After a time, because machines were expensive, people began to share machines more effectively. Thus the era of multiprogramming was born"Programming Semantics for Multiprogrammed Computations" by Jack B. Dennis, Earl C. Van Horn. Communications of the ACM, Volume 9, Number 3, March 1966. An early paper (but not the first) on multiprogramming., in which multiple processes were ready to run at a given time, and the OS would switch between them, for example when one decided to perform an I/O. Doing so increased the effective utilization of the CPU. Such increases in efficiency were particularly important in those days where each machine cost hundreds of thousands or even millions of dollars (and you thought your Mac was expensive!). ...