Introduced by ComputerCraft 1.7 (and therefore requiring Minecraft 1.7.10 or later), the Command Computer is a more powerful version of the Advanced Computer, having direct access to Minecraft operator commands. They are therefore uncraftable, only available to OP-status players via the creative inventory, and can only be directly interacted with by the same such players. For example, unlike other computers, they will not boot from an external Disk Drive.
Although regular players cannot directly access these systems, it's quite possible for OPs to write scripts that allow others a controlled level of interaction via the touch-sensitive Advanced Monitor block, or via Rednet, or via other peripherals. For example, one may wish to write a script that displays the server TPS rate on an external monitor for other players to observe. Obviously, when doing so, one should take care not to inadvertently grant other players full access to the system's capabilities.
Supports all the methods available to a Computer or Turtle.