关注
Swapping program from disk to memory.
System maintains a ready queue consisting of all processes whose memory images are on the backing store or in memory and are ready to run. Whenever the CPU scheduler decides to execute a process, it calls the dispatcher. The dispatcher checks to see whether the next process in the queue is in memory. If not and if there is no free memory, the dispatcher swaps out a process currently in memory and swaps in the desired process.
