In modern computers many processes run at once, to ensure each program has a fair share of resources each one is run for a period, when a program is taken out to let another run it is placed on the end of the run queue, and the program at the head of the run queue is then allowed to execute.

Processes are also removed from the run queue when they ask to sleep, are waiting on a resource to become available, or have been terminated.

In UNIX or Linux the sar command is used to check the run queue.