A REVIEW OF MEMORY ALLOCATION AND MANAGEMENT IN COMPUTER SYSTEMS

A REVIEW OF MEMORY ALLOCATION AND MANAGEMENT IN COMPUTER SYSTEMS ABSTRACT In this paper I have described the memory management and allocation techniques in computer systems. The purpose of writing this survey paper is to elaborate the concept of memory allocation and management in computer systems because of the significance of memory component in computer system’s hardware. It is apparent from the work of computer scientists that effective and efficient main memory management and virtual memory management in computer systems improves the computer system’s performance by increasing throughput and processor utilization and by decreasing the response time and turnaround time. Firstly I have compared Uniprogramming system with Multiprogramming system. After comparison I found that Multiprogramming systems are quite better than Uniprogramming systems from the point of view of memory utilization. Also the functionality of operating system routines which are responsible for user’s memory partitioning must be improved to get better system performance in Multiprogramming system .In Uniprogramming system , the processor remains idle most of the time but dividing the memory into partitions for holding multiple processes as in Multiprogramming system does not solve the problem of idleness of a processor. Mostly all of the processes need I/O access, therefore processor also remain idle in Multiprogramming system. We have also discussed resource memory in detail and compared fixed partitioning with variable partitioning. After in depth study we found that variable partitioning is more advantageous than fixed partitioning because reallocation of page frames is impossible in fixed partitioning for a set of active processes at time instant‘t’. In this paper we have also discussed MIPS R2/3000 machine virtual to real address mapping in detail so that virtual to real address mapping can be understood through a machine’s architecture and example. KEYWORDS Queues, Long Term Queues, Short Term Queues, I/O Queues, Swapping, Processor Scheduling, Fixed Partitioning, Variable Partitioning, Page Frames, Pages, Virtual Memory, Physical Memory, Processor Utilization, Throughput, Response Time, Turnaround Tim