PERFORMANCE MODE LS DEVALUATION

ABS TRACT The System Process Model (SPM) is used to represent behavior of the multiprogramming module of a compnter system operating under a demand paging strategy. It models the system as a network of states and assoc-iated queues. The level of multiprog:rnaing is varied by changing the average n-unber of pages that users are permitted in main memory. De-vices are explicitly characterized by parameters representative of their behavior, and sample programs run unde2e CP-6 ( are parameterized in terms of I/O and paging activity for use in representing jobs in the system. With the intention of using this model for performance projection, a notential oroblem characteristi of such virtual memory systems is discussed. The thrasingr-oroblem is defined as the less than optimal ise of system resources resulting from excessive competition for primary memory. Novel definitions for pinpointing this degredation are prorosed. SPM is then used as a vehicle to analyze the operations of a CP-6