The procedure kill handles both kinds of process termination. It may be explicitly called by a process that makes a kill request or it may be called implicitly when a process terminates normally. An existing process requests for a new process to be created. The new process does not begin execution but is in the suspended state. Thus kill also handles normal termination.
Multiprocessing is useful for several reasons, which are dis- cussed below.
In the absence of multiprocessing, a single application is run at a time. Thus a single user is serviced at a time. It is also useful to have several applications running simul- taneously on behalf of the same user. For instance an editor and a compiler could run together. The editor could be higher prior- ity so that the compiler runs only when the editor is waiting for user input.