Dynamic memory allocation systems for minimizing internal fragmentation

Abstract

Internal fragmentation is a phenomenon of a paging environment. Memory is divided into equal size blocks called pages, and when a job requests memory space, it receives an integral number of pages. The difference between the amount of space actually required and the amount allocated is wasted space and is referred to as internal fragmentation. In comparison a segmentation environment allocates exactly the amount of space required. However, this system is subject to another type of wasted memory called external fragmentation. This fragmentation occurs when allocation requests cannot be filled even though there is available space in memory (which is either too small to be useful or too scattered). It has been shown by Randell [6] and Purdom & Steigler [5] that internal fragmentation is a more serious problem than external fragmentation and therefore we will direct our attention to it.