Please help me explaining this in simpler words:
If we were to swap out process P1 and swap in process P2, the
I/O operation might then attempt to use memory that now belongs to process
P2. There are two main solutions to this problem: never swap a process with
pending I/O, or execute I/O operations only into operating-system buffers.
Transfers between operating-system buffers and process memory then occur
only when the process is swapped in. Note that this double buffering itself