Abstract: Disclosed is a storage device, which includes a nonvolatile memory device, and a controller that controls the nonvolatile memory device. In response to a first command, a barrier command, and a second command being received from an external host device, the controller supports an order guarantee between the first command and the second command. Each of the first command and the second command is selected from two or more different commands. In response to a request from the external host device, the controller circuitry is configured to provide the external host device with a device descriptor associated with the ordering.

Abstract: Disclosed are a robot cleaner and a self testing method thereof. The robot cleaner performs a self test when being initially operated or when required by a user. This may prevent malfunctions or breakdowns of the robot cleaner. Furthermore, the robot cleaner senses states of components and sensors mounted therein, and performs a self test based on characteristics, output values, etc. of the components and the sensors. This may prevent accidents or errors which may occur as the robot cleaner operates.