Abstract: A disk block controller and file system support large extended files by using special logical blocks which contain a number of sequential physical disk blocks. The disk block controller includes a file creation support unit, an extended management unit, a first and second management units, and an allocation unit. The file creation support unit separates free physical disk blocks into a region with a small number of sequential empty physical disk block spaces and a region with a large number of sequential empty physical disk block spaces, and allocates these regions to different parts of the disk. The extended management unit manages a start and sequential block numbers for sequential empty physical disk blocks having specified entries and is utilized for extended files whose logical block size is an integral multiple of a physical block.