Patent ID: 7136884

Claim:
A file management method that has file management information for managing contiguous blocks on a disc as an extent and for grouping the extent as a file and managing the file, comprising: when creating a new directory on the disc, reserving as a reserved area, for recording file management information on the file, a file or a data area in the directory; and reserving a directory block having a predetermined size in the reserved area for recording a file entry of the directory and a file identifier descriptor of the directory, wherein an area is reserved as a directory block group in a size of an arbitrary integral multiple of a size of the directory block, wherein concurrently with the process of reserving the directory block group, an area for recording for a file entry, which corresponds to a required area for recording the file whose file identifier descriptor can be described in the directory, and at least a portion of the file is reserved in the reserved area initially and at one time.