Command queue
（重定向自Command queuing）
In computer science, a command queue is a queue for enabling the delay of command execution, either in order of priority, on a first-in first-out basis, or in any order that serves the current purpose. Instead of waiting each command to be executed before sending the next one, the program just puts all the commands in the queue and goes on doing other things while the queue is processed by the executor component (e.g. hard drive).