Some embodiments of the invention relate to selecting a data protection scheme, such as, for example, mirroring or RAID, for a content unit based on power-related metadata associated with the content unit. Under circumstances in which data is duplexed, when data is duplexed again after data that is generally saved as backup data was accessed for reading and writing, in order to efficiently duplex data, update places of both original data and sub-data updated during the duplexing of data is interrupted are registered on an access information management table of an original disk control unit. As a result, it is possible to obtain an information display panel having a stable information display state such as an image. As a result of this determination, when the position of the moving body enters into a distance range for one of the stages, the position of this moving body is wirelessly reported to a control center. The head comprises: at least one write head element including a magnetic pole layer; and at least one first heating element generating a heat to expand the at least one write head element thermally, the at least one first heating element being contacted with the magnetic pole layer. And the device further comprising a second silicide layer formed on the second polysilicon layer and being thicker than the first silicide layer.