3000	 Segment Sizes and Lifetimes in Algol Programs	 The characteristics of the virtual memory requirements of a sample of Algol programs have been measured. Distributions are presented for thesizes of memory requests and for their holding times lifetimes . The results are presented in terms of Johnston s contour model and a simple abstract machine. They provide new empirical evidence of certain aspects of the construction and behavior of real programs and some of their implications for the design of virtual memory systems are presented and discussed. virtual memory program behavior segmentation storage allocation Algol contour model
