Hardware Estimation of a Process' Primary Memory Requirements A minor hardware extension to the Honeywell 6180 processor is demonstrated to allow the primary memory requirements of a process in Multics to be approximated. The additional hardware required for this estimate to be computed consists of a program accessible register containing the miss rate of the associative memory used for page table words. This primary memory requirement estimate was employed in an experimental version of Multics to control the level of multiprogramming in the system and to bill for memory usage. The resulting system's tuning parameters display configuration insensitivity, and it is conjectured that the system would also track shifts in the referencing characteristics of its workload and keep the system in tune. CACM September, 1977 Giffor, D. K. primary memory requirement, virtual memory, level of multiprogramming, associative memory, working set, resource allocation, LRU stack model, referencing characteristics 4.32 4.35 4.6 6.36 CA770906 JB December 27, 1977 1:05 PM 1892 4 2928 1901 4 2928 2085 4 2928 2095 4 2928 2218 4 2928 2277 4 2928 2319 4 2928 2329 4 2928 2358 4 2928 2373 4 2928 2380 4 2928 2434 4 2928 2499 4 2928 2501 4 2928 2582 4 2928 2629 4 2928 2669 4 2928 2828 4 2928 2847 4 2928 2863 4 2928 2868 4 2928 2881 4 2928 2928 4 2928 2928 4 2928 2928 4 2928 2928 4 2928 2928 4 2928 2951 4 2928 2996 4 2928 3006 4 2928 3046 4 2928 3067 4 2928 3098 4 2928 3107 4 2928 3127 4 2928 1751 5 2928 2277 5 2928 2380 5 2928 2522 5 2928 2569 5 2928 2928 5 2928 2928 5 2928 2928 5 2928