A backup device comprising a secondary user-carried device for backing up data from a primary portable data storage device is described. The backup device includes a short-range wireless communication link, a communication interface for communicating with the primary portable data storage device over the communication link to receive data to back up and to check for removal of the primary portable data storage device and storage for storing data received over the communication link from the primary portable data storage device. A triggering device is also provided for triggering an alert procedure when the primary portable data storage device is out of range for a predetermined period.