ABSTRACT
A queue is an arrangement for the members of a set to appear for an activity, complete it, and leave. Such appearances are called arrivals. The activity is called service. The members arriving for service are called customers, even though they may not be humans in every case. Customers may be physical devices, or even abstract entities such as electromagnetic signals representing a data packet. The arrangement is also called a queueing system. The word queueing is also spelled queuing, now-a-days. Queues occur extensively in all walks of life and in many technological systems. They gained importance in machine shops with a demand for quick repair turn around during World War II. The simplest examples of queues are those in banks with customers being served by tellers, calls appearing at telephone exchanges, and population dynamics of, say, rabbits and foxes in a forest.
