Decomposability, Instabilities, and Saturation in Multiprogramming Systems A step-by-step approach to model the dynamic behavior and evaluate the performance of computing systems is proposed. It is based on a technique of variable aggregation and the concept of nearly decomposable system, both borrowed from Econometrics. This approach is taken in order to identify in multiprogramming paging systems (i) unstable regimes of operations and (ii) critical computing loads which bring the system into states of saturation. This analysis leads to a more complete definition of the circumstances in which "thrashing" can set in. CACM July, 1975 Courtois, P. J. multiprogramming, paging, performance evaluation, saturation, instabilities, thrashing, aggregation, system levels, hierarchy,networks of queues 4.31 4.32 8.1 8.2 CA750701 JB January 9, 1978 10:39 AM 1828 4 2741 1854 4 2741 1877 4 2741 1892 4 2741 1960 4 2741 2068 4 2741 2150 4 2741 2317 4 2741 2319 4 2741 2377 4 2741 2342 4 2741 2376 4 2741 2379 4 2741 2424 4 2741 2482 4 2741 2618 4 2741 2632 4 2741 2704 4 2741 2712 4 2741 2723 4 2741 2738 4 2741 2740 4 2741 2741 4 2741 2741 4 2741 2741 4 2741 2867 4 2741 3070 4 2741 3184 4 2741 1526 5 2741 1749 5 2741 2454 5 2741 2741 5 2741 2741 5 2741 2741 5 2741 3016 5 2741 3070 5 2741 3153 5 2741 1805 6 2741 1901 6 2741 2454 6 2741 2741 6 2741 2741 6 2741 2741 6 2741 2891 6 2741 2988 6 2741