(A) generalization of operational approach from single class to multiple classes

Abstract

The operational method, which was first formally introduced by Buzen, differs significantly from the conventional stochastic modeling approach and is based on a set of concepts that correspond naturally and directly to observed properties of real computer systems. Main advantage of this method is that only some directly measurable data are needed for computer performance evaluation. This thesis attempts to generalize the recent results of Denning and Buzen [12]. A number of algorithms for computer performance evaluation, e.g., throughput, response time, utilization, are derived through our generalized operational method. While many of the results presented by Denning and Buzen apply to models with two job classes, batch and interactive, our generalized model can represent more accurately and with more levels of detail the operation of computer systems. In addition, this model can answer many other problems arising in computer systems modeling which to date have been unsolvable. A comparision with traditional stochastic method is given. Finally, we pose some open problems motivated by the foregoing results.