Memory Management Paper

Memory Management Paper

Patrick Maxfield

POS/355

September 18, 2013

Eugene Gorbatov

Memory Management Paper

Memory management is vital in multiprogramming systems, without it most of the time your processor would be idle. There are five requirements that memory management needs to satisfy. The purpose of this paper is to explain these requirements what they are, what they do, and their purpose.

The first requirement that needs to be satisfied is relocation; this is basically what it sounds like. Not knowing were the program is going to be placed in the system, you need to have the ability to pull it up and move it or relocate it as needed. The programmer also has to deal with address requirements. The processor and the operating system have to translate the memory references found in the program into a physical memory address which will reflect the current location of the program in the main memory.

The next requirement that needs to be satisfied is called protection. Whether it is accidental or intentional each process needs to be protected from unwanted interference. Programs in other processes should not be able to reference memory locations in a process for the purpose of reading or writing without permission. All memory references generated by a process must be checked at run time to ensure that they refer only to the memory space allocated to them. A user process cannot access any portion of the operating system. A program in one process cannot branch to an instruction in another process. A program in one process cannot access the data area of another process without making special arrangements. The processor must have the ability to abort such instructions at the time of execution. The memory protection requirement must be satisfied by the processor (hardware) not the operating system (software). The reason for this is the operating system cannot anticipate all the memory references that a program will make. To accomplish the processor hardware...