Write a short note about context switch.

Switching the CPU to another process needs saving the state of the old process and loading the saved state for the new process. This task is recognized as a context switch. The context of a process is symbolize in the PCB of a process it includes the value of the process state, CPU registers, and memory-management information. When a context switch takes place, the kernel accumulates 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 for the reason that to machine depending on the memory speed the number of registers that have to be copied, and the subsistence of special instructions. Usual speed range from 1 to 1000 microseconds. Context-switch times are extremely dependent on hardware support.