KR20060100833A - Method of managing a file system area efficiently - Google Patents

Abstract

The present invention relates to a method for efficiently managing a file system area of a write once high density optical disc. The present invention is characterized in that the logical address for the file system area is preempted continuously by filling the area where the file system is to be recorded after the format of the optical disc with dummy data. In addition, a file system reserved area is separately designated after the last position of the data area, and data of the actual file system is recorded therein. Furthermore, if the number of entries in the defect list is more than the limit or the risk is detected, the file system area of the preempted logical address is relocated from the beginning to the end in the file system reserved area. Accordingly, the defect entries dispersed by performing a plurality of update operations can be replaced with one continuous defect entry, and the movement distance of the optical pickup can be shortened, thereby allowing data to be read without wasting seek time.

Description

Method of managing a file system area efficiently

1 to 4 are diagrams for explaining a method of managing a file system area of a conventional write once high density optical disc.

Fig. 1 shows the result of formatting a write once high density optical disc,

2 shows the result of recording the file system and data after the format is completed.

3 illustrates a result of changing contents of a file system according to a file update request from a host.

4 illustrates a problem with a conventional method for managing file system areas.

5 to 11 are diagrams for explaining a method of managing a file system area of a write once high density optical disc according to the present invention.

5 illustrates a method of preempting a file system area after formatting is completed according to an embodiment of the present invention.

6 shows a result of recording a file system according to an embodiment of the present invention.

7 is a view illustrating a result of changing contents of a file system according to a file update request from a host according to an embodiment of the present invention.

FIG. 8 illustrates a path to which an optical pickup of an optical disk device should move when following the method of managing a file system according to the present invention.

9 illustrates a method of continuously rearranging data in a file system area that is discontinuously spread according to another embodiment of the present invention.

10 illustrates a method of preempting a file system area after formatting a disc in accordance with the present invention.

Figure 11 illustrates a method for relocating discretely spread file system regions in accordance with the present invention.

The present invention relates to a write once high density optical disc, and more particularly, to a method for efficiently managing a file system area of a write once high density optical disc.

Recently, a Blu-ray Disc (BD-RE) has been developed as a high-density optical disc capable of recording high quality video data for a long time. Such a high density optical disc is largely divided into a file system area and a data area. In particular, the file system area in which file entries are stored is frequently updated for the same logical address. This is because whenever the contents of a file indicated by a file entry are modified, added or deleted, the contents of the file system area must be changed.

On the other hand, a high-density optical disc that can be written once can only be written once for the same physical address. However, as described above, the file system area must be frequently updated for the same logical address. To solve this problem, a defect management method is used. In other words, by recording the mapping information of the logical address and the physical address in the defect management area (hereinafter referred to as DMA) of the high density optical disc, it is logically rewritten many times at the same address even though the physical address is recorded in the new area. The update is to make it look as possible.

Each time an update is performed, a defect entry including mapping information of a logical address and a physical address is added to a defect list (hereinafter abbreviated as DFL). The defect list is not limited in the number of rewrites, but the number of entries in the total defect list is limited. In a contiguous area, even a plurality of logical addresses can be represented by one defect entry. However, as the update is performed a plurality of times, the file system area may be finely divided and the number of discontinuous areas may increase, thereby exhausting the number of defect entries. If all defect entries are used, a problem arises in that new data can no longer be recorded.

More specifically, FIGS. 1 to 4 are diagrams for explaining a method of managing a file system area of a conventional write once high density optical disc.

Fig. 1 shows the result of formatting a write once high density optical disc. Referring to FIG. 1, a formatted optical disc is largely divided into a file system area and a data area, and reserved, and a defect management area for storing information related to the structure and defect management of the disc. (DMA) is also reserved. In particular, a disc definition structure (DDS) indicating a start position and a last position of a data area and a defect list (DFL) including a plurality of defect entries are recorded in the DMA area. As described above, the total number of entries in the defect list is fixed.

2 shows the result of recording the file system and data after the format is completed. Referring to Fig. 2, a file entry indicating the location of a file in the data area is recorded in the file system area. In the defect list (DFL), a defect entry indicating mapping information of a logical address and a physical address is recorded. In the illustrated example, since the physical addresses 1 to 4 are consecutively present with respect to the logical addresses 1 to 4, mapping information may be represented by one defect entry.

3 shows the result of the contents of the file system being changed in response to a file update request from the host side. Referring to FIG. 3, as a file operation such as adding, deleting, or modifying a file is performed on the host side, the content of a corresponding file entry in the file system area is changed. At this time, the host requests that the optical disc perform rewriting to the same logical address as if it is a rewritable medium. However, in the high-density optical disc that can only be written once, the newly added or modified file entry information cannot be rewritten to the same physical address of the file system area, and therefore is written to a new physically empty space. In the example shown, file entry 1 is allocated an empty area (file entry 1 ') after the last address of the data area without changing the logical address. In addition, the mapping information of the physical address to the logical address is changed in the defect list of the DMA area.

Thus, physically a new file entry 1 'or 3' is added, but from the host's point of view it appears that the update has been performed at the same logical address. As file entry data that has been continuously recorded in the file system area is divided into several pieces, the number of defect entries also increases. That is, as the update of the file is repeated, the discontinuous area increases gradually, and when the number of defect entries is more than the limited range, a problem may occur that no further update is possible.

4 illustrates a problem with a conventional method for managing file system areas. Referring to FIG. 4, a path in which an optical pickup of the optical disk device should move to read a file system recorded according to the file system area management method of FIGS. 1 to 3 is indicated by a dotted line, and an arrow indicates an actual read operation. Indicates a location. That is, in order to read the data on the optical disc in the order of 1'-2-3'-4, the optical pickup first moves to the added 1 'position, then back to the 2 position, and then to the 3' position Go to the position of. As a result, the seek time is wasted due to the movement of the optical pickup. Since data cannot be read during the seek time, a disconnection phenomenon may occur when playing back a moving image requiring seamless playback.

Accordingly, a technical problem to be solved by the present invention is to provide a method for efficiently managing a file system area so that data can be read without wasting seek time.

In addition, another technical problem to be achieved in the present invention is to provide a method for efficiently managing a file system area so that the file can be updated without being limited to the number of defect entries.

According to the present invention, there is provided a method of managing a file system area of a write-once high-density optical disc, the method comprising: (a) preempting a file system area requiring frequent updating; (b) reserving a separate physically contiguous area to record actual data of the preempted file system area; And (c) recording actual data of the preempted file system area in the reserved area.

Further, a method of managing a file system area of a write-once high density optical disc includes the steps of: (d) relocating data of a reserved area discontinuously dispersed in a physically contiguous area by updating repeatedly; And (e) replacing the plurality of defect list entries representing mapping information between the logical address and the physical address with one defect list entry based on the relocated data.

Step (a) preferably fills the file system area with dummy data to preempt the logical address of the file system area.

Preferably, the reserved area in step (b) is located after the last address of the data area.

Preferably, the reserved area in step (b) is larger than the size of the preempted file system area,

It is particularly preferred that the reserved area in step (b) be large enough to include space for relocating discontinuous data to physically contiguous areas in addition to the size of the preempted file system area.

In addition, the update is preferably performed according to a defect management scheme.

On the other hand, according to another field of the present invention, the above-described technical problem is achieved by a computer-readable recording medium having recorded thereon a program for causing a computer to execute the above-described method for managing a file system area of a write once high density optical disc. .

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of the present invention will be described in detail. 5 to 11 are diagrams illustrating a method of managing a file system area of a write once high density optical disc according to the present invention.

The present invention is characterized in that the logical address for the file system area is preempted continuously by filling the area where the file system is to be recorded after the format of the optical disc with dummy data. In addition, a file system reserved area is separately designated after the last position of the data area, and data of the actual file system is recorded therein. Furthermore, if the number of entries in the defect list exceeds the limit or the risk is detected, the file system area of the preempted logical address is relocated from the beginning to the end in the file system reserved area. As a result, the defect entry dispersed by performing a plurality of update operations may be replaced with one consecutive defect entry.

More specifically, FIG. 5 illustrates a method of preempting a file system area after formatting is completed according to an embodiment of the present invention.

Referring to FIG. 5, the file system area 100 is filled with dummy data before the file system and the data file are recorded on the optical disk in the format complete as shown in FIG. Preempt logical addresses. It also reserves the area where the actual filesystem will be recorded. The file system reserved area 102 is preferably located after the last position of the data area. In addition, it is particularly preferable that the size of the file system reserved area 102 be reserved enough space to include free space for defect list replacement, which will be described later, in addition to the original file system size. By filling the file system area 100 with meaningless data, it is possible to preempt logical addresses assigned to this area from being used in other areas.

6 shows a result of recording a file system according to an embodiment of the present invention.

Referring to FIG. 6, the host recognizes that the file entry is written to the logical address of the file system area as shown in FIG. In reality, however, file system data is recorded in the file system reserved area 102 instead of the file system area 100 shown in FIG. That is, the logical address of the file system is assigned the address of the preemptive file system area 100, but the physical address where the actual data is recorded is assigned the address of the file system reserved area 102. In addition, mapping information between logical addresses and physical addresses is recorded in the defect list of the DMA area.

7 is a diagram illustrating a result of a change in a file system content according to a file update request from a host according to an embodiment of the present invention.

Referring to FIG. 7, an example of the case where file entries 1 and 3 are updated to file entries 1 'and 3' is shown. New file entries 1 'and 3' are updated in the empty space of the file system reserved area 102 where the actual file entries are written, and the mapping information of the logical address and the physical address according to the update result is a defect list of the DMA area. Recorded at 106.

FIG. 8 illustrates a path to which an optical pickup of an optical disk device should move when following the method of managing a file system according to the present invention.

Referring to FIG. 8, the path in which the optical pickup moves to read data on the optical disc in the order of 1'-2-3'-4 is significantly shorter than in FIG. It fills the file system area 100 with dummy data, preempts logical addresses, and designates the file system reserved area 102 separately to record the data of the actual file system and subsequently updated data close to the reserved area 102. This is because the movement path of the optical pickup is shortened. As the optical pickup has a shorter movement path, seek time is reduced, and data can be read in a relatively faster time.

Meanwhile, FIG. 9 illustrates a method of continuously rearranging data in a file system area that is discontinuously spread according to another embodiment of the present invention.

For example, in the case where the physical addresses are continuous as described above in FIG. 2, it can be represented as one defect entry, while the physical address of the file system reserved area 102 is changed due to the update as shown in FIG. 7. The discontinuity increases the number of defect entries to four. Since the number of entries in the defect list, which is mapping information for linking logical addresses and physical addresses, is finite, when the number of entries is exhausted, data can no longer be updated.

In order to prevent such a problem, another embodiment of the present invention provides a method of rewriting data on a physical address that has been discontinuously dispersed in a physically contiguous area. Referring to FIG. 9, data may be rearranged so that data that is logically continuous but physically discontinuous is recorded in a physically continuous area. That is, a portion of the logically contiguous area can be rewritten to the physically contiguous area. The number of entries in the defect list of the DMA area is now reduced to one. That is, the mapping information of the logical address and the physical address of the relocated region may be replaced with one continuous defect entry in the plurality of discrete defect entries, thereby reducing the number of entries in the defect list. 7 and 9 show an example in which four defect list entries are replaced with one defect list entry. In addition, data rearranged to a physically continuous area may read data at a time without movement of the optical pickup.

The method for efficiently managing the file system area according to the present invention described above is as follows.

10 illustrates a method of preempting a file system area after formatting a disc in accordance with the present invention.

Referring to FIG. 10, a new high-density optical disc is inserted into an optical disc apparatus, formatted, and then filled with file system regions with meaningless data, thereby preempting the file system region 100 requiring frequent data update (step 200). A predetermined area for recording actual data of the preempted file system area is reserved (step 202). File system reserved area 102 is preferably allocated after the last address of the data area. File entries, which are the actual data of the preempted region, are now written to the file system reserved region 102 (step 204). By filling the file system area 100 with the dummy data and specifying the file system reserved area 102 separately, the file entry data of the actual file system and later updated file entry data are recorded close to the reserved area 102. As a result, the optical pickup has a shorter moving path, which reduces seek time, thereby allowing data to be read in a relatively faster time.

On the other hand, Figure 11 illustrates a method for rearranging discontinuously spread file system regions in accordance with the present invention.

Referring to FIG. 11, as the update is repeated, the physical address is divided into a plurality of discrete areas, thereby increasing the number of entries in the defect list that maps the logical address and the physical address. When the number of entries in the defect list is checked (step 210), when the total number is greater than or equal to the limited range (step 212), the file system data is rearranged in a physically continuous area of the file system reserved area 102 (214). step). That is, a portion of the logically contiguous area is rewritten to the physically contiguous area. Accordingly, the mapping information of the logical address and the physical address of the relocated region is replaced with one consecutive defect entry from the plurality of discrete defect entries (step 216), and the number of entries in the defect list can be reduced.

According to the relocation method described above, it is possible to reduce the number of entries in the defect list, thereby preventing a case where the number of defect entries is exhausted and new data can no longer be recorded. In addition, data rearranged to a physically continuous area may read data at a time without movement of the optical pickup.

On the other hand, the method for efficiently managing the file system area according to the present invention can be created by a computer program. Codes and code segments constituting the program can be easily inferred by a computer programmer in the art. In addition, the program is stored in a computer readable media, and read and executed by a computer to implement a method for efficiently managing a file system area. The information storage medium includes a magnetic recording medium, an optical recording medium, and a carrier wave medium.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the appended claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

As described above, according to the present invention, there is provided a method and apparatus for efficiently managing a file system area of a write-once high density optical disc.

That is, in the related art, there was no method of reducing the distance of the optical pickup to read the file system after frequent updating of data, but according to the present invention, the movement distance of the optical pickup is relatively reduced, thereby reading data without wasting time. You can make this possible.

In addition, although there is no conventional method for reducing the number of entries in the defect list, according to the present invention, the number of entries in the defect list can be reduced by relocating the logically contiguous area to the physically contiguous reserved area. . As a result, it is possible to prevent the case where the number of defect entries is exhausted and it is no longer possible to record new data. In addition, data rearranged to a physically continuous area may read data at a time without movement of the optical pickup.

Claims (8)

In the file system area management method of a write once high density optical disc, (a) preempting a file system area requiring frequent updates; (b) reserving a separate physically contiguous area to record actual data of said preempted file system area; And (c) recording actual data of the preempted file system area in the reserved area. The method of claim 1, (d) relocating the data of the reserved area that has been dispersed discontinuously and repeatedly to a physically contiguous area; And (e) replacing a plurality of defect list entries representing mapping information between logical addresses and physical addresses with one defect list entry based on the relocated data. The method according to claim 1 or 2, In step (a), the file system area is filled with dummy data to preempt the logical address of the file system area. The method according to claim 1 or 2, And the reserved area in step (b) is located after the last address of the data area. The method according to claim 1 or 2, And wherein the reserved area in step (b) is larger than the size of the preempted file system area. The method according to claim 1 or 2, And wherein the reserved area in step (b) is large enough to include space for relocating discontinuous data to physically contiguous areas in addition to the size of the preempted file system area. The method according to claim 1 or 2, And wherein the updating is performed according to a defect management scheme. A computer-readable recording medium having recorded thereon a program for causing a computer to execute the method for managing a file system area of the write once high density optical disc according to any one of claims 1 to 7.

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