TOPIC 17.2.1
Queue Theory, and Differences in Queues

A queue is similar to a checkout line in a supermarket. The first person in line is servide first, and the other customers enter the line only at eh end and wait to be servied. Queue nodes are removed only from the head of the queue, and are inserted only at the tail of the queue. For this reason, a queue is referred to as a FIFO (First-In First-Out) data structure.

Queues have many applications in computer systems. Queues are used to support print spooling. A multiuser environment may only have a single printer. Many users may be generation output to be printed. If the printer is busy, other output may still be generated. These are "spooled" to disk where they wait in a queue until the printer becomes available.

For more information on queues, consult the following links:

• General Queue Theory