Memory Management

Memory Management Paper

Darren Blackwell

POS/355

January 16, 2014

C. Randall Shirley

Memory is a crucial component in a computer system. The operating system and various applications must be loaded into the memory system before the ability to be executed. The efficiency of memory management can affect the entire system. Examining the nature of the execution of programs helps determine the requirements which include relocation, protection, sharing, logical and physical organization.

The main memory of a multiprogramming system is commonly shared by many processes. Programmers do not typically know what other programs will be in the main memory at the time of their program initiation. Address mapping and relocation are key to boosting operation. After a program or app is created and loaded into the memory, it is ready for use. For the operating system to dispatch the app the locations of process control information, the execution stack, and code entry must be known for access. Within the program there must also be various instructions in the form of references. “jmp somewhere”, is an example of this where “Somewhere” in this case, is a reference for a location in the memory where the next instruction is to be implemented. For example, next could be move AX, which somewhere else is the memory location where the value is to be moved into AX. These locations are called the logical addresses for the entry point of the program, which is 0. These references are set in place before the program is loaded. The logical addresses essentially make up what is called a logical address space. Once the program is loaded, there must be an ability to transform the logical addresses into physical ones. These physical or real addresses will point to instructions and destination data which make up the physical address space.

Protection is always a necessity against deliberate and unintentional threats. Of course permission should be required for any program to access memory...