A fast-food restaurant has four kinds of employees: $(1)$ order takers, who take customers’ orders; $(2)$ cooks, who prepare the food; $(3)$ packaging specialists, who stuff the food into bags; and $(4)$ cashiers, who give the bags to customers and take their money. Each employee can be regarded as a communicating sequential process. What form of interprocess communication do they use? Relate this model to processes in UNIX.
