Patent ID: 7634613

Claim:
A write-once memory device having a recording medium on which data can be written only once on the bit basis and which includes an entity data recording area where entity data of a file is recorded and a management data recording area where management data for the write-once format for supervising said files in accordance with a hierarchical directory structure is recorded, wherein a file entry, specifying a file recorded on a recording medium, a root entry for specifying the uppermost order directory in the hierarchical directory structure and a sub-entry for specifying a sub-directory in the hierarchical directory structure, are recorded in the management data recording area, in association with the file, root directory and the sub-directory generated, respectively; the name of the file specified, the information identifying the root entry or the sub-entry specifying a parent directory of said file and the information for identifying a recorded position of the entity data of said file(s) are included in the file entry; the name of the sub-directory specified and the information identifying the root entry or the sub-entry specifying a parent directory of the sub-directory are included in the sub-entry; the physical format of said entity data recording area is identified with the physical format of an effective area of a recording medium of a rewritable memory device capable of re-writing data a plural number of times and having the effective area and a reserve area for data substitution, said effective area being an area where entity data is recorded; the physical format of said management data recording area is identified with the physical format of said reserve area in said rewritable memory device; said root entry, one or more sub-entries and one or more file entries are recorded on one page; a management address is set for each page of said management data recording area; and said management address is included in said sub-entry and said file entry as the information identifying the root entry or the sub-entry of the parent directory.