Method and apparatus for managing power consumption on a bus

An information storage device includes a cartridge removably inserted into a cradle that has a drive module releasably coupled to an interface module. The interface module can be operatively coupled by a cable to a remote system. Communications through the cable conform to an industry-standard protocol. The storage device can receive power from either the cable or an external power source. The interface module can detect a change in the source of its operating power during normal system operation, and ensure that this is reported through the cable.