According to one embodiment, a method for writing a file to a plurality of media includes loading a parent medium into a first drive to retrieve ID information about the parent medium from metadata, writing a first file part to the parent medium and, at about a same time, saving a file name, attribute information, and attribute information about the first file part to the parent medium as metadata, loading a child medium into a second drive in order to write subsequent file parts and retrieving ID information about the child medium from metadata, writing the subsequent file parts to the child medium and, at about a same time, saving the ID information and attribute information about the subsequent file parts to the parent medium, and additionally saving the ID information about the child medium and the attribute information about the subsequent file parts as metadata in the child medium.