Abstract: According to one embodiment, a magnetic head includes first and second magnetic poles, a conductive part, an element part, and first to fourth terminals. The conductive part is electrically insulated from the first and second magnetic poles. The first and second terminals are electrically connected to the conductive part. The element part is provided between the first and second magnetic poles and electrically connected to the first and second magnetic poles. The element part is conductive. The third terminal is electrically connected to the first magnetic pole. The fourth terminal is electrically connected to the second magnetic pole. A first magnetic pole temperature in a first state is higher than a second magnetic pole temperature of the second magnetic pole in the first state. A first current is supplied between the first and second terminals in the first state.

Abstract: A server includes a monitoring unit that monitors operation states of one or more physical servers in use on which same applications operate, a synchronization unit that synchronizes the data between one of the physical servers in use and one of virtual servers in a standby physical server, and a switching unit that, when the monitoring unit has detected that a failure has occurred in the operation of one of the physical servers in use, that operates a second application of the same applications while referring to a piece of the data on the one of the virtual servers synchronized by the synchronization unit with the data on the one of the physical servers in use, and that switches operation from the one of the virtual servers to the standby physical server.

Abstract: A server includes a monitoring unit that monitors operation states of one or more physical servers in use on which same applications operate, a synchronization unit that synchronizes the data between one of the physical servers in use and one of virtual servers in a standby physical server, and a switching unit that, when the monitoring unit has detected that a failure has occurred in the operation of one of the physical servers in use, that operates a second application of the same applications while referring to a piece of the data on the one of the virtual servers synchronized by the synchronization unit with the data on the one of the physical servers in use, and that switches operation from the one of the virtual servers to the standby physical server.