-> Switching the CPU to another process requires saving the state of the old process and loading the saved state for the new process.
-> This task is known as a context switch.
-> The context of a process is represented in the PCB of a process; it includes the value of the CPU registers, the process state and memory-management information.
-> When a context switch occurs, the kernel saves the context of the old process in its PCB and loads the saved context of the new process scheduled to run.
-> Context-switch time is pure overhead, because the system does no useful work while switching.
-> Its speed varies from machine to machine, depending on the memory speed, the number of registers that must be copied, and the existence of special instructions.
Post a Comment