A message queue is a destination to which messages can be sent. One program sends a message to another by putting the message on a message queue. The message remains on the queue until the receiving application retrieves it. For example, PowerExchange for WebSphere MQ reads messages from a queue and writes messages to a queue. The queue can either be a volatile buffer area in the memory of a computer or a data set on a permanent storage device set aside by the queue manager to hold messages.