Os Memory Management Questions Medium
Memory swapping is a technique used in operating systems to manage the limited physical memory available to the system. It involves temporarily moving some portions of a process's memory from the main memory (RAM) to secondary storage (usually the hard disk) when the system is running out of available memory.
When a process is running, it requires a certain amount of memory to store its instructions, data, and stack. However, the physical memory available in a system is limited, and if multiple processes are running simultaneously, there may not be enough memory to accommodate all of them. This can lead to performance degradation or even system crashes.
To overcome this limitation, memory swapping is employed. When the operating system detects that the available physical memory is becoming scarce, it selects a portion of a process's memory that is not currently being used and transfers it to the secondary storage. This frees up space in the physical memory for other processes to use.
The swapped-out memory is stored in a special area on the hard disk called the swap space or page file. The operating system keeps track of the location of each swapped-out memory page and maintains a page table to map the virtual memory addresses of the process to their corresponding physical or swapped-out locations.
When a process needs to access a memory page that has been swapped out, a page fault occurs. The operating system then retrieves the required page from the swap space back into the physical memory. This process is known as swapping in or page-in.
Memory swapping allows the system to effectively utilize the available physical memory by temporarily storing less frequently used or idle portions of a process's memory on the secondary storage. However, swapping comes with a performance cost, as accessing data from the secondary storage is significantly slower compared to accessing data from the main memory. Therefore, excessive swapping can lead to increased response times and decreased overall system performance.
In summary, memory swapping is a memory management technique used by operating systems to optimize the utilization of physical memory by temporarily moving less frequently used portions of a process's memory to secondary storage, freeing up space for other processes.