MEMORY ALLOCATION SCHEMES AND SYNCHRONIZATION FOR OPERATING SYSTEM

Abstract

~.Titi a view to develop an operating system,different allocation policies and synchronization techniques have been reviewed first. FIFF(9,6) and SJFS>(9,6) for fetch and first-fit (6,3) and Best-F it(6,13) for placement have. be?n critically discussed: The new.pollcies, i.e. BEST•SIZS for fetch and IMdtptable First-Fit for placement have been proposed. It is demonstrated that the different combi-nations of these policies result in 9 different uni-policy. schemes and the same number of bi-policy schemes for memory allocation. The simulation of jobs has been made by using a uniform random function. By exploiting the simulaticn , 9 different uni-policy schemes and 2 bi-policy schemes have been studied on DEC system-10. Graphs have been plotted for a number of parameters v/s number of allocation calls. L comparative study of various schemes has been given. Further the proposed adaptable First-fit schemes have been studied for different ranges of memory. Considering memory as a resource, mutual exclusion part of synchronization is coded by using different techniques viz. ,Boolean, semaphore and