Paging is a memory management technique used by operating systems to bring processes or programs from secondary storage (such as a hard disk) into the main memory (RAM) in the form of fixed-size blocks called pages. These pages are a logical concept used for efficient data access.
In paging, the main memory is divided into smaller blocks called frames, with a fixed frame size. The size of these frames must match the size of the pages to avoid external fragmentation, which is when free memory becomes scattered in small chunks. This allows for optimal memory utilization and prevents wasted space.
While paging helps in efficient memory allocation, it also introduces overhead in managing page tables and address translation. Additionally, if the page size is not chosen carefully, it may result in internal fragmentation, which is when memory is wasted within a page due to varying sizes of processes. Thus, careful consideration of page size and efficient management of page tables are important factors in implementing effective paging in an operating system.