File transfer system, file transfer method, and file transfer program

Abstract

A file transfer system transfers a target file updated in a first computer to a second computer for each part obtained by dividing the target file and includes: an update recording unit that records an update position of the target file in the first computer as an offset flag; an update determination unit that refers to the offset flag and determines presence or absence of update for each part of the target file; and a transfer unit that transfers the part determined to have update by the update determination unit to the second computer, in which when re-update in which the target file is updated after the transfer unit starts transferring any part included in the target file occurs, the transfer unit transfers, to the second computer, a re-update part that is the part updated by the re-update, regardless of whether or not the re-update part has already been transferred.