A process needs to be in memory to be executed. A process, however, can be swapped temporarily out of memory to a backing store, and then brought back into memory for continued execution.

For example, assume a multiprogramming environment with a round-robin CPU-scheduling algorithm. When a quantum expires, the memory manager will start to swap out the process that just finished, and to swap in another process to the memory space that has been freed.

Currently, standard swapping is used in few systems. It requires too much swapping time and provides too little execution time to be a reasonable memory-management solution.