General Equations for Idealized CPU-I/O Overlap Configurations General equations are derived for estimating the maximum possible utilization of main storage partitions, CPU and I/O devices under different conditions in an idealized CPU-I/O overlap model of multiprogrammed computer systems. The equations are directly applicable to any configuration consisting of sets of identical CPU's I/O processors, main storage partitions and user tasks. Examples are provided to illustrate the use of the equations to compute effective processing time per record and expected timesharing response time under both balanced and unbalanced resource utilization conditions. CACM June, 1978 Teory, T. Blocking, buffering, input/output, overlap, performance, resource allocation, throughput, timesharing 3.72 4.30 4.41 8.1 CA780609 DH February 8, 1979 4:35 PM 3088 5 3088 3088 5 3088 3088 5 3088