Os Memory Management Questions Medium
Memory paging is a memory management technique used by operating systems to efficiently allocate and manage memory resources. It involves dividing the physical memory into fixed-sized blocks called pages and the logical memory into fixed-sized blocks called frames. The size of a page is typically a power of 2, such as 4KB or 8KB.
The main idea behind memory paging is to allow processes to use more memory than what is physically available by utilizing secondary storage, such as a hard disk. When a process requests memory, the operating system assigns it a certain number of pages from the available pool. These pages do not have to be contiguous in physical memory, which allows for efficient memory allocation.
The mapping between logical pages and physical frames is maintained in a data structure called the page table. Each entry in the page table contains the mapping information, such as the physical frame number corresponding to a logical page. The page table is used by the memory management unit (MMU) to translate logical addresses to physical addresses during memory accesses.
When a process accesses a memory location, the MMU checks the page table to determine the physical frame associated with the logical page. If the page is not present in physical memory (known as a page fault), the operating system retrieves the required page from secondary storage and brings it into a free frame in physical memory. The page table is then updated to reflect the new mapping.
Memory paging provides several benefits. Firstly, it allows for efficient memory allocation as pages can be allocated and deallocated independently. It also enables processes to use more memory than what is physically available, as pages can be swapped in and out of secondary storage as needed. This helps in maximizing the utilization of available memory resources.
However, memory paging also introduces overhead due to the need for page table lookups and potential page faults. To mitigate this overhead, operating systems employ various techniques such as page replacement algorithms (e.g., LRU, FIFO) to determine which pages to evict from physical memory when it becomes full.
In summary, memory paging is a memory management technique that allows for efficient allocation and management of memory resources in operating systems. It enables processes to use more memory than what is physically available and provides flexibility in memory allocation and deallocation.