Dispatcher:

It is a module whose responsibility is to give control of a CPU to a
process selected by short term scheduler for execution. It is invoked by short-term
scheduler. The time taken by dispatcher to switch from one process to another is
called as dispatch latency. To keep this switching overhead to minimum dispatcher
should be as fast as possible.
The function of a dispatcher involves the following:
 Switching context (saving the execution environment of current process and
loading the execution environment of different process)
 Switching to user mode
 Jumping to a proper location in the user program to restart the program