Memory Management in Operating System

Main Memory refers to a physical memory that is the internal memory to the computer. The word main is used to distinguish it from external mass storage devices such as disk drives. Main memory is also known as RAM. The computer is able to change only data that is in main memory. Therefore, every program we execute and every file we access must be copied from a storage device into main memory.

All the programs are loaded in the main memory for execution. Sometimes complete program is loaded into the memory, but some times a certain part or routine of the program is loaded into the main memory only when it is called by the program, this mechanism is called Dynamic Loading, this enhance the performance.

Also, at times one program is dependent on some other program. In such a case, rather than loading all the dependent programs, CPU links the dependent programs to the main executing program when its required. This mechanism is known as Dynamic Linking.

Memory Management in Operating System

Memory Management Virtual Memory File System Banker's Algorithm Bounded Buffer Problem Comparison of Scheduling Algorithms Dining Philosophers Problem Readers writer problem Secondary Storage Structure System Calls

Logical and Physical address Space, 
Swapping, 
Memory allocation,

Contiguous Memory allocation, 
Fixed and variable partition, 
Internal and External

fragmentation and Compaction, 
Paging – Principle of operation, 
Page allocation, 
Hardware support for paging, 
Protection and sharing, 
Disadvantages of paging, 
Segmentation, 
Virtual Memory.