Simulation of a Multiproc[3s0r Computer System

Computer simulators have generally been constructed at one of two levels of detail: the instruction level or the bit-time (logic) level. Such simulators have been produced for many years now and their value is well established. By contrast, only minor attention has been given to simulating computer systems at a macroscopic level. One type of macro-level simulator has been reported recently by Hutchinson '; in his model the simulated system consists of an entire computation center, with the computer representing merely a component. As computer systems grow increasingly complex the macro-level modeling of such systems becomes increasingly useful. By applying such a model one can predict the performance of the system on a prescribed job load, and/or evaluate the effect of various parameters on system performance. In this paper we report on an experimental model that is applicable to a class of multiprocessor operating systems including IBM's Direct-Couple Operating System (DCS). The model has enabled us to evaluate the effect of selected hardware parameters, software parameters and environmental parameters on the performance of a DCS-type multiprocessor operating system. The principal measures of system performance produced by the model are statistics on turnaround time, throughput, equipment utilization, and job queues. The paper is in eight sections. Section 2 discusses