File system managing method and recording medium

1. A file system managing method, when file data composed of management data and data bodies is written in a recording medium comprising multiple recording layers stacked on a substrate, the recording medium having a recording area continuously formed from a most inner layer of the recording layers adjacent to the substrate to an outermost layer of the recording layers, the method comprising:

dividing the recording area into a management data recording area and a data bodies recording area at any boundary, the management data recording area including an end of the recording area in the most inner recording layer adjacent to the substrate, the data bodies recording area including an other end of the recording area in the outermost recording layer;

writing the management data in the management data recording area; and writing the data bodies in the data body recording area.

2. The file system managing method according to claim 1 , wherein the data body recording area has a storage capacity equal to a storage capacity of the management data recording area.

3. The file system managing method according to claim 2 , wherein the recording layers are even-numbered and a boundary between the data body recording area and the management data recording area is situated on an end of the recording layer.

4. The file system managing method according to claim 2 , wherein the recording layers are odd-numbered and a boundary between the data body recording area and the management data recording area is situated on a midpoint of the recording layer.

5. The file system managing method according to claim 4 , wherein in consideration of a spiral direction of the recording layer, the management data recording area is allocated upstream in the spiral direction.

6. The file system managing method according to claim 2 , wherein in consideration of a spiral direction of the recording layer, the data body recording area has a recording starting point upstream in the spiral direction.

7. The file system managing method according to claim 2 , when the data body recording area has an insufficient writing area and the management data recording area has an empty space,

the method further comprising:

dividing the empty space into a free-space data body recording area and a free-space management data recording area allocated to an area continuing from the management data recording area, at a ratio between a data amount of the written management data and a data amount of the written data bodies.

8. The file system managing method according to claim 7 , wherein a boundary between the free-space data body recording area and the management data recording area is situated on an end of the recording layer such that the end of the recording layer is adjacent, in a writing direction, to a boundary determined according to the ratio between the data amounts.

9. The file system managing method according to claim 2 , when the data body recording area has an insufficient writing area and the management data recording area has an empty space,

the method further comprising:

determining a standard deviation of data amounts of the written data bodies;

selecting one of the data amounts of the data bodies as a reference data amount of the data bodies, the selected data amount being closest to a deviation value of 50;

determining a standard deviation of data amounts of the written management data;

selecting one of the data amounts of the management data as a reference data amount of the management data, the selected data amount being closest to a deviation value of 50; and

dividing the empty space into a free-space data body recording area and a free-space management data recording area allocated to an area continuing from the management data recording area, at a ratio between the reference data amount of the data bodies and the reference data amount of the management data.

10. The file system managing method according to claim 2 , wherein the file data is managed by a UDF file system, the management data is a File Entry, and the data body is a File Body.

11. The file system managing method according to claim 2 , wherein the recording medium is an optical disc.

12. The file system managing method according to claim 1 , when the data body recording area has an insufficient writing area and the management data recording area has an empty space,

the method further comprising:

dividing the empty space into a free-space data body recording area and a free-space management data recording area allocated to an area continuing from the management data recording area, at a ratio between a data amount of the written management data and a data amount of the written data bodies.

13. The file system managing method according to claim 1 , when the data body recording area has an insufficient writing area and the management data recording area has an empty space,

the method further comprising:

determining a standard deviation of data amounts of the written data bodies;

selecting one of the data amounts of the data bodies as a reference data amount of the data bodies, the selected data amount being closest to a deviation value of 50;

determining a standard deviation of data amounts of the written management data;

selecting one of the data amounts of the management data as a reference data amount of the management data, the selected data amount being closest to a deviation value of 50; and

dividing the empty space into a free-space data body recording area and a free-space management data recording area allocated to an area continuing from the management data recording area, at a ratio between the reference data amount of the data bodies and the reference data amount of the management data.

14. A recording medium in which file data composed of management data and data bodies is recorded and a recording area is formed of multiple recording layers stacked on a substrate, the recording area being continuously formed from a most inner layer of the recording layers adjacent to the substrate to an outermost layer of the recording layers,

wherein the recording area is divided into a management data recording area and a data bodies recording area at any boundary, the management data recording area including an end of the recording area in the inner most recording layer adjacent to the substrate, the data bodies recording area including an other end of the recording area in the outermost recording layer,

the management data is recorded in the management data recording area, and

the data bodies are recorded in the data body recording area.

15. The recording medium according to claim 14 , wherein the data body recording area has a storage capacity equal to a storage capacity of the management data recording area.

16. The recording medium according to claim 15 , wherein the data bodies are recorded in the overall data body recording area and an empty space other than the recorded management data in the management data recording area is further divided into a free-space data body recording area and a free-space management data recording area.

17. The recording medium according to claim 14 , wherein the data bodies are recorded in the overall data body recording area and an empty space other than the recorded management data in the management data recording area is further divided into a free-space data body recording area and a free-space management data recording area.