An Experimental Model of System/360 The problem of predicting the performance of modern computer systems is formidable. One general technique which can ease this problem is macroscopic simulation. This paper reports on the applicability of that technique to System/360. The paper describes an experimental model of System/360-its hardware, software, and its environment. The measures of system performance produced by the model consist of statistics relating to turnaround time, throughput, hardware utilization, software utilization, and queueing processes. The model is mechanized in SIMSCRIPT and consists of some 1750 statements. An auxiliary programs, the Job Generator, creates automatically the properties of System/360 jobs that get simulated. CACM November, 1967 Katz, J. H. CA671102 JB February 26,1978 3:20 PM 1518 5 1518 1518 5 1518 1518 5 1518 1805 5 1518 1912 5 1518 1518 6 1518 1518 6 1518 1572 6 1518 1748 6 1518