FILE SYSTEM

A file system capable of performing bandwidth setting is realized. Further, a bandwidth assuring function and a prefetching function are added thereto, and are organically coupled to a bandwidth setting function, thereby realizing a real-time remote file system. For these purposes, a bandwidth setting request issued by an application 302 is fed to a bandwidth setting part 305 through an extended API 313. The bandwidth setting part 305 sets bandwidths, respectively, for transmission bandwidth control parts 311 and 314 and a prefetching amount control part 310. The transmission bandwidth control parts 311 and 314 and the prefetching amount control part 310 respectively control a transmission bandwidth and control the amount of prefetching on the basis of the bandwidths respectively set.