Abstract: To provide a wearable computer that allows a user to back up important data on a device immediately at hand for the user. A data backup system is provided including a wearable computer and a portable information terminal that carries out communication with the wearable computer, the portable information terminal reads the history of updates and backups from a storage device, compares the time of the last backup indicated by the backup history with the update history, and searches for data that has been newly updated since the time of the last backup. The portable information terminal extracts the newly updated data as backup data, and sends the extracted backup data. The wearable computer receives the backup data, and writes the backup data in the storage device.

Abstract: Owning a mechanical key alone does not allow knowing whether an automobile, dwelling, etc. is locked or unlocked. Furthermore, if a plurality of keys are owned, it is difficult to identify at a glance a key for a particular object. Furthermore, when a toll parking is used, a parking time has been estimated by taking notes on the time when the automobile is parked, which has caused a laborious work. Furthermore, even if an on-vehicle GPS unit is mounted, it has been necessary to take notes on map information of a surrounding area before going out of the automobile. Accordingly, the present invention provides a key with display capability that allows information relating to an object to be grasped even from a location remote from the object. Display means for displaying an image and receiving means for receiving information from an object that requires a key are provided, and information relating to the object is received from the object and then displayed.

Abstract: A dynamic access random access card is provided with a dynamic random access memory and a source for generating a plurality of reference clock pulses. A control circuit generates refresh operations of the dynamic access memory in response to the plurality of reference clock pulses generated by the source, the initiation of the refresh operations being independent of any external refresh request. The refresh operations are interrupted and the dynamic random access memory is set to a standby condition upon detection of a predetermined external signal, thereby permitting read/write operations of the dynamic random access memory.