Provided is an information system for preserving data of a storage device in a computer that repeats the connection to and disconnection from a communication network. The computer acquires data to be written into the storage device and manages the update status of the storage device, transfers the data written into the storage device to the storage controller independent from the writing of data into the storage device when the computer is in a communicable state with the storage controller, and discontinues the transfer of data written into the storage device to the storage controller and manages the transfer status when the computer is not in a communicable state with the storage controller.