Patent ID: 7447672

Claim:
A 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 for recording entity data of a file and a management data recording area for recording management data supervising the file recorded by a hierarchical directory structure; wherein in said management data recording area, a file entry for specifying the file recorded on the recording medium in association with the file generated by an operating system, a root entry for specifying the uppermost order directory in the hierarchical directory structure in association with the root directory generated by the operating system, and a sub-entry for specifying a sub-directory in the hierarchical directory structure in association with the sub-directory generated by the operating system, are recorded as said management data, respectively; wherein the name of the file specified, the information identifying the root entry or the sub-entry specifying the parent directory of the file, and the information for identifying a recording position of the entity data of the file, are included in said file entry; wherein the name of the sub-directory specified and the information identifying the root entry or the sub-entry specifying the parent directory of said subdirectory are included in said sub-entry; wherein said entity data recording area and the management data recording area are each divided into blocks, each of which represents a predetermined data unit; a logical address is recorded in each block of said entity data recording area; only entity data of a file is recorded in one block of said entity data recording area; wherein entity data of one file is recorded in one or more blocks formed by consecutive logical addresses; wherein said block is formed by a plurality of pages each being of a predetermined data volume; wherein one root entry, a sub-entry and a file entry are recorded on one page; a management address is set in each page of said management data recording area; and wherein the management address for a root entry or a sub-entry specifying a parent directory is included in said sub-entry and in said file entry as being the information specifying said root entry or the sub-entry of the parent directory.