Memory Management

One of the primary objectives of memory management is to keep track of memory locations regardless of if they are in use or free and how much memory each process uses and for how long. Memory management also involves mapping logical address to physical addresses. During this process there are three different states that the addresses can be in: symbolic, relative, and physical. There are a few methods of memory compaction regarding memory management including swapping and fragmentation. According to Tutorials Point (n.d) “Swapping is a mechanism in which a process can be swapped temporarily out of main memory to secondary storage and make that memory available to other processes.” Fragmentation involves organizing memory into one large block rather than having it separated by open, free memory. Memory allocation is another major function that helps partition memory between low memory and high memory to ensure that the memory is used as efficiently as possible. Segmentation is the process of breaking down each job into different sizes and lengths to consume less space compared to paging. Paging allows memory to be stored in non-contiguously as frames and pages rather than together in the same location.

The physical address space, also known as the “real address”, is defined as the address generated by the memory management unit (MMU) and always remains constant. Silberschatz et. al. (2014) states that "The virtual address space of a process refers to the logical (or virtual) view of how a process is stored in memory." When looking at how physical and virtual space are similar and different, Tutorials Point (n.d) states that “Virtual and physical addresses are the same in compile-time and load-time address-binding schemes. Virtual and physical addresses differ in execution-time address-binding scheme.”

References:

Silberschatz, A., Galvin, P. B., & Gagne, G. (2014). Operating system concepts essentials (2nd ed.). Retrieved from https://redshelf.com/

Tutorials Point. (n.d.). Operating system - Memory Management. Retrieved January 13, 2022, from https://www.tutorialspoint.com/operating_system/os_memory_management.htm

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