Measures, models and measurements for time-shared computer utilities

Recent literature1-6has summarized many of the characteristics of time-shared systems which have been or are being built for experimental or commercial application. Fortunately system designers are not waiting for a formal theory before experimenting. Unfortunately some of the results are so diverse in effectiveness that greater emphasis on analysis must be achieved. If predictability cannot lower the risks associated with the tremendous investments required to implement information processing utilities, progress in this field may be markedly decreased. The present paper presents a characterization of the time-sharing system environment, a set of measures associated with the system, an integrated summary of models and a discussion of measurements. In the final section new proposals for systems, measures, models and measurements are considered.