Os Memory Management Questions
Paging is a memory management technique used by operating systems to divide the physical memory into fixed-size blocks called pages. These pages are typically of equal size and are used to store both the program instructions and data.
When a program is executed, the operating system divides it into smaller units called pages. These pages are then loaded into the physical memory, which is divided into frames of the same size as the pages. The mapping between the logical pages and physical frames is maintained in a data structure called the page table.
When a program needs to access a specific memory address, the operating system translates the logical address to a physical address using the page table. This translation involves finding the corresponding page in the page table and determining the physical frame where it is stored. The offset within the page is then added to the base address of the physical frame to obtain the final physical address.
Paging allows for efficient memory allocation and utilization as it allows the operating system to load only the required pages into the physical memory, rather than loading the entire program. It also provides protection and isolation between different processes, as each process has its own page table and cannot access the memory of other processes.
Additionally, paging enables virtual memory, which allows programs to use more memory than physically available. When the physical memory becomes full, the operating system can swap out less frequently used pages to disk, freeing up space for other pages. These swapped-out pages can be brought back into memory when needed, resulting in the illusion of a larger memory space for the program.