Memory Management

Memory Management Requirements

Sunny Hill

Introduction to Operating/POS355

June 10, 2013

Bhupinder Singh

Memory Management Requirements

The best way to begin discussing the requirements of memory management would be first to define what memory management is. Memory can be divided into two parts: one part is for the operating system, and the other is for the program currently running. Subdividing the memory into order to allow several processes is the definition of memory management. According to this week’s readings, “Effective memory management is vital in a multiprogramming system.” Within memory management there are five requirements: relocation, protection, sharing, logical organization, and physical organization.

Main memory is shared among a number of processes. Relocation allows the swapping of active processes in and out of main memory to allow maximum use of the processor. When a program is swapped out it is impossible for it to be placed into the same area that it was previously. Relocation comes into play within this situation. It relocates that process to a different area of memory.

The second requirement that memory management satisfies is protection. This requirement protects each process from unwanted interference from other processes either accidental or intentional. Use of the relocation requirement it makes the protection requirement more difficult to satisfy. This is so because the location to where a process may be relocated to is unpredictable, and it does not provide for time to check absolute addresses at compile time to ensure protection. Protection also does not permit a user process to access any portion of the operating system.

The third requirement of memory management is sharing. Sharing within memory management allows several processes to access the same section of main memory. This sharing is controlled access without compromising essential protection. Sharing allows...