A method implemented by a status-monitoring device connected between a storage device and a corresponding output unit includes: a) determining presence of a storage device according to a first packet from the storage device; b) when it is determined that the storage device is present, generating a pulse signal according to a second packet from the storage device; c) generating a driving signal indicating a status associated with the storage device according to at least a logic level of the pulse signal; and d) sending the driving signal to the output unit for driving the output unit to output an output signal indicating the status.