Transient-Free Working-Set Statistics Transient-free average working set size and transient-free missing-page rate for a finite sample of a reference string are defined. Use of these statistics is appropriate if the contents of the working set at the start of the recorded string are unknown. If a certain stationarity condition holds, these statistics provide unbiased estimates of expected working-set sizes, missing-page probabilities, and in terreference distance probabilities. Two other pairs of estimators are shown to be biased. Expressions for the transient-free statistics are obtained in terms of in terval statistics. Several methods of computation are discussed, the usefulness of each depending on length of the sample, number of distinct references, and the amount of main storage available to the computer performing the calculations. In particular, methods are described for handling long strings containing many distinct page names. CACM February, 1977 Easton, M. C. Bennett, B. T. working set, estimation program behavior 4.3 4.6 5.5 CA770204 JB December 30, 1977 2:40 AM 1892 4 2996 1901 4 2996 2085 4 2996 2095 4 2996 2218 4 2996 2277 4 2996 2319 4 2996 2329 4 2996 2358 4 2996 2373 4 2996 2374 4 2996 2380 4 2996 2380 4 2996 2434 4 2996 2499 4 2996 2450 4 2996 2501 4 2996 2582 4 2996 2595 4 2996 2669 4 2996 2828 4 2996 2863 4 2996 2881 4 2996 2928 4 2996 2996 4 2996 2996 4 2996 2996 4 2996 3006 4 2996 3006 4 2996 3006 4 2996 3067 4 2996 3067 4 2996 3067 4 2996 1751 5 2996 2373 5 2996 2595 5 2996 2996 5 2996 2996 5 2996 2996 5 2996