HK1060645B - Method for creating defect management information in an information recording medium and apparatus and medium based on said method - Google Patents

Description

Method and apparatus for managing defect locations in a data storage medium

Technical Field

The present invention relates to a method of handling defects generated on an information recording medium, and more particularly, to a method of managing defect locations in a data storage medium, and a recording medium using the same.

Background

With the advent of CDs (compact discs), optical discs have been widely used. Further, with the popularization of DVDs (digital versatile discs), the demand for optical discs is expected to steadily increase. Optical disks include read-only disks (e.g., CD-ROM and DVD-ROM), write-once disks (e.g., CD-R and DVD-R), and rewritable disks (e.g., CD-RW and DVD-RAM). The standard formats of CD-RW and DVD-RAM have been promulgated, and standardization of VDR (video disk recorder) is still in progress.

For a rewritable optical disc such as a DVD-RAM, it is necessary to deal with defects occurring on its recording surface so as not to cause data to be written in a sector in which a read error detected exceeds a predetermined level (hereinafter referred to as "defective" or "bad" sector), thereby obtaining a highly reliable write/playback operation. For this purpose, defect handling must be performed such that the addresses of defective sectors are stored in a defect handling table of the optical disc, while data access for writing or reading of defective sectors is prohibited.

As shown in fig. 1, a lead-in area, a data area, and a lead-out area are provided in a rewritable physical area of the DVD-RAM. The data area is divided into 24 successive groups, one guard area before and after each group. Each set consists of a user area for recording data and a spare area providing a storage area for replacing defective portions of the user area.

The data area is also composed of a plurality of sectors, each of which includes 16 sectors. The location of each sector is specified by a physical address uniquely given to each sector. When data is recorded, each sector is sequentially assigned an LSN (logical sector number) except for the defective sector.

Defect processing information, or the physical address of a defective sector in the data area, is stored in a DMA (defective processing area). As shown in fig. 1, DMAs are provided in four places, two in the lead-in area and two in the lead-out area, to prevent defects occurring in the four DMAs themselves.

The DMA consists of two ECC (error correction code) sectors or 32 sectors. The first ECC section is composed of one sector for DDS (disc definition structure) and 15 other sectors for PDL (primary defect list). 16 sectors of the second ECC section are used for SDL (secondary defect list).

Examples of DDS, PDL, and SDL are given in table 1, table 2, and table 3, respectively.

[ TABLE 1] DDS Structure

Position of	Size (in bytes)	Content providing method and apparatus
			0～1	2	DDS identifier (0A0Ah)
2	1	Reserved (00h)
			3	1	Disk acceptance mark
4～7	4	DDS/PDL
			8～9	2	Number of groups
10～2047	2038	Reserved (00h)

[ Table 2] PDL Structure

Position of	Size (in bytes)	Content providing method and apparatus
			0～1	2	PDL identifier (0001h)
2～3	2	Number of entries in PDL
			4～7	4	Address of the first bad sector
8～11	4	Address of the second bad sector
			··	··	··

[ Table 3] SDL Structure

Position of	Size (in bytes)	Content providing method and apparatus
			0～1	2	SDL identifier (0002h)
2～3	2	Reserved (00h)
			4～7	4	SDL update counter
8～15	8	Spare area full flag
			16～21	6	Reserved (00h)
22～23	2	Number of entries in SDL
			24～31	8	Address of the first bad sector and address of the first generation sector
···	···	···

Referring to the DVD-RAM, a method of creating and processing defect processing information such as PDL and SDL is explained below.

PDL creation and processing (under write operation)

The optical disc, or DVD-RAM, is tested by the manufacturer to determine the validity of each sector. The test method is to write data into each sector and then read the data out, thereby checking the sector for quality. Sectors tested to have read errors exceeding a predetermined level are classified as defective sectors at the time of manufacture, and their physical addresses are sequentially stored in the PDL, as shown in fig. 1.

When a user requests to write data to the optical disc, a write command is sent to the optical disc drive, and then data starts to be sequentially written in unused sectors of the user area, as shown in fig. 2. Each time data is written to a target sector, the physical addresses of the target sector are compared to those of defective sectors in the PDL. When the address of the target sector matches any of the addresses of defective sectors in the PDL, the target sector is skipped and data is written to the next valid sector. This mechanism of compensating for defective sectors is called "slipping replacement".

In case of a user area without defective sectors, data is written only to the user area, as shown in the upper part of fig. 2. On the other hand, if there are defective sectors in the PDL, sectors in the spare area equal to the number of defective sectors in the user area are used for sector replacement, as shown in the lower part of fig. 2.

One sector may be deteriorated in quality due to a cyclic playback operation of the optical disc, thereby becoming a defective sector. Such defective sectors are considered "grown" defective sectors. Therefore, when data is written to the optical disk, each sector not listed in the PDL is checked to determine whether it has a grown defect. Each sector that is deemed defective complies with a sector slipping algorithm, the address of which is added to the PDL to ensure that data is not written to the defective sector before proceeding to the next write operation sector verification process.

Thus, as the write operation is repeated, the number of entries in the PDL increases.

The criteria for concluding that a sector is bad are as follows. Sectors with ECC (hereinafter, referred to as "ECC sectors") are composed of 182 bytes × 13 lines of data, as shown in fig. 5, and a specific PID (physical identification) is assigned to each sector. The PID is written in four reserved locations per sector. If there are three or more errors in the PID readout of a sector, or the number of rows having four or more byte errors in a sector is one or more, the sector is determined to be a defective sector. When the number of rows having four or more byte errors in one ECC sector is six or more, the ECC sector is classified as a bad sector.

SDL creation and processing (in playback operation)

When the optical disc is used, there is a possibility that a defect occurs in a sector within the disc. Therefore, when the optical disc is played back, sectors not listed in the PDL are checked to determine whether they become grown defective sectors. If one sector is determined to be bad, data recorded in 16 logical sectors of an ECC sector having bad sectors (bad ECC sector) is transferred to a valid ECC sector, which is sequentially available in the spare area, as shown in fig. 3. This mechanism is called "linear permutation". The physical address of the first or first sector of the defective ECC block and the physical address of the first sector of the replacement ECC block are then stored as an entry of the SDL.

When the available spare section in the current group is missing, the full flag corresponding to the group is set to 1 in the SDL and the active spare section is borrowed from the spare area in the other group for linear replacement.

In a playback operation, an ECC sector is declared bad when the number of rows having four or more bytes in error in the ECC sector is 8 or more, or when one or more sectors have more than three PID reads generated.

When data is written to or read from the DVD-RAM, a logical sector address sent from the associated host computer to the DVD-RAM drive is translated into a physical target address. Next, the PDL is rechecked to determine whether or not the slide adjustment is necessary. That is, the physical target address is compared with the addresses of defective sectors in the PDL. If the sector of the physical target address is determined to be defective, the defective sector is skipped and the following sectors are examined until a valid sector is found. The physical target address is then adjusted to locate the next valid sector. In a replay operation, the physical target address is compared to a list of SDLs to check if sector replacement is required. If the physical target address matches any of the SDLs, the physical target address of the replacement sector is read from the SDL.

In the case of optical discs for storing moving images or speech, real-time playback of audio/video data is important. However, when a grown defective sector not listed in the SDL is detected in playback, the playback operation may be interrupted for a short time corresponding to a sector replacement requiring data to be moved on the optical disc. In this case, the reproduction speed of the data recorded on the defective sector becomes slow, resulting in a short interruption of the reproduction of the audio/video data.

At the time of playback, no processing for new defective sectors not listed in PDL and SDL may become a method of solving the short-time interruption caused by linear replacement. However, in this case, when the written audio/video data is erased and then new audio/video data is rewritten to the VDR, new data may be written in a defective sector or section. As a result, a read error of the newly recorded audio/video data on the defective sector inevitably occurs.

Disclosure of Invention

Accordingly, it is a primary object of the present invention to provide a method of creating defect management information capable of reproducing audio/video data on an information recording medium in real time regardless of the presence of a defective sector; and to avoid writing data into defective sectors when new audio/video data is written onto the recording medium. An apparatus and an optical disc for implementing the method are also provided.

To achieve this object, the present invention provides a method of managing defect locations in a data storage medium including basic defect management information identifying at least a defect location through at least one of a formatting mode, a recording mode, or a playback mode, the method comprising: receiving a playback command for playing back data recorded at a predetermined position; determining whether the location is defective during the playback mode; temporarily generating defect management information for the location based on the result of the determining step; and adding the temporary defect management information to the basic defect management information.

The recording medium according to the present invention is characterized by comprising: a basic defect management area identifying a defective location by at least one of a format mode, a recording mode, or a playback mode; and a temporary defect management area for temporarily identifying a defect location based on at least the current playback mode, wherein the basic defect management area allows transmission of at least a defect location found from the temporary defect management area by the current playback mode.

According to the present invention, there is provided a method of managing a defective location in a data storage medium including basic defect management information identifying at least the defective location by at least one of a format mode, a recording mode, or a playback mode, the method comprising: receiving a playback command for playing back data recorded at a predetermined position; determining whether the location is defective during the playback mode; temporarily generating defect management information for the location based on the result of the determining step; and transmitting the temporary defect management information to the basic defect management information according to the command.

Drawings

The included drawings provide further explanation of the invention and demonstrate preferred embodiments of the invention. The drawings and the following description serve to explain the principles of the invention.

In the drawings:

fig. 1 is a layout diagram showing a division of a rewritable area of an optical disc and a defect list;

FIG. 2 illustrates a slipping replacement algorithm in a write operation;

FIG. 3 illustrates a linear permutation algorithm in a replay operation;

fig. 4 is a sectional view showing a preferred embodiment of the optical disc recording/reproducing apparatus of the present invention;

FIG. 5 shows an arrangement of a sector with ECC;

FIG. 6 is a flowchart showing a process of writing to the optical disc;

fig. 7 is a flowchart showing a playback process of audio/video (a/V) data from an optical disc according to the method of creating defect management information of the present invention;

FIG. 8 is a flowchart showing a playback process for non A/V data from an optical disk;

FIG. 9 is a flowchart showing a process of updating the defect list when A/V data is erased; while

Fig. 10 is a layout diagram showing a rewritable region of an optical disc according to the present invention.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 4 depicts a partial sectional view of a VDR player implementing the defect management information creation method according to the present invention. The VDR player comprises: an optical pickup device 10 that reads or writes data from or to an optical disc; a servo controller 110 for controlling the optical pickup device 10; a read signal processing unit 40 for sorting data to be reproduced from the optical disc; a PID detector 50 for testing PID of the data read from the optical disc; an SDL manager 90 for judging whether a sector is defective based on a read error of the detected PID, and also for selecting a new defective sector not listed in the SDL by using defect information in the SDL; a playback unit 60 for decompressing and processing a/V data received from the readout signal processing unit 40; an interface RAM130 for temporarily storing A/V data transmitted to the host computer; a T-PDL (temporary PDL) manager 80 for judging whether a sector is defective based on a readout error of the A/V data, and for selecting a new defective sector not listed in the T-PDL; a memory 70 for temporarily storing PDL, SDL and T-PDL; an address manager 120 for acquiring a physical address of a sector on which data to be erased is recorded, when a data erase operation is requested; a write signal processing unit 30 for moving information in a physical address matching an address stored in the T-PDL to the PDL of the optical disc; and a laser beam controller 20 for controlling a laser for writing data to the optical disc.

Referring to fig. 6 or the flowchart of fig. 9 and fig. 4, a method of creating defect management information of an optical disc according to the present invention will be described in detail.

Once the optical disc drive starts reproducing the optical disc, PDL and SDL are read out from the lead-in area of the optical disc and stored in the PDL memory 70a and the SDL memory 70c, respectively. Defective sectors stored in the PDL are skipped, and data is read out and reproduced from the corresponding replacement sectors, instead of the bad sectors stored in the SDL.

At the same time, the data read from the optical disk by the optical disk pickup device 10 is input to the read signal processing unit 40, where the data is classified to determine whether or not the data is a/V data. Through the PID detector 50, non A/V data or control data is provided to the SDL manager 90. The SDL manager determines whether the non-A/V data has a read error. If so, the ECC block containing the sector in which the non-A/V data is recorded is replaced with the replacement ECC block of the spare area. Therefore, the non-A/V data is recorded there. The PID of the first sector of the defective ECC field and the PID of the first sector of the replacement ECC field are stored in the SDL memory 70 c.

On the other hand, if A/V data is reproduced, the A/V data is transmitted to the host computer through the reproducing unit 60 and the interface RAM 130. Whether the A/V data has a read error is judged by the T-PDL manager 80. The PIDs of the sectors judged to be defective are stored in the T-PDL memory 70 b.

In this way, PIDs of defective sectors in which A/V data is recorded are stored in the T-PDL memory 70b, and PIDs of defective sectors in which non-A/V data is recorded are stored in the SDL memory 70 c. After the playback operation is completed, the defect information added to the T-PDL memory and the SDL memory is written in the respective reserved areas on the optical disc, as shown in fig. 10. Thereafter, when the disc is reproduced again, the defective sectors stored in the PDL and the SDL are skipped, and the defective sectors stored in the T-PDL are reproduced instead of being skipped. As a result, even if the sector containing the A/V data is judged to be defective, the A/V data is reproduced in real time without any sector replacement.

When a user requests to erase data on an optical disc in order to record new data, a signal informing an erase operation is sent to an optical disc drive. Upon receiving the signal, PDL, SDL, and T-PDL on the optical disk are read out and stored in the respective memories 70a, 70b, and 70 c. The PID of the sector containing the data to be erased is compared with the PID of the defective sector stored in the T-PDL memory 70 b. If there is a matching PID, it is moved from T-PDL memory 70b to PDL memory 70a via a bus (not shown). As a result, during the overwrite operation, the defective sector is allowed to slip, while data is prohibited from being written to the defective sector associated with the matching PID. After the rewrite operation is completed, the updated PDL is written to a reserved area on the optical disc.

On the other hand, in this embodiment of the present invention, it is possible that the defective sector in which non-a/V data is recorded is not replaced by the replacement sector, but the PID thereof may be stored in the T-PDL memory 70b, as is the defective sector in which a/V data is recorded.

Hereinafter, a description will be given of a write operation of the method of creating defect handling information according to the present invention with reference to fig. 6. This operation is the same as the prior art.

If a write command is input to the optical disc drive (S10), it is first determined whether the write operation is completed (S13). Then, the PDL stored in the memory 70a is checked to determine whether or not the physical address of the target sector is included in the PDL (S15).

If it is judged that the physical address of the target sector is included in the PDL, the target sector is skipped, followed by judgment of the next sector (S17). The process from step S13 is repeated for the next target sector. On the other hand, if it is determined in the step S15 that the target sector is not included in the PDL, the target sector is checked to determine whether it has become a defective sector after the PDL is updated last time. That is, after the four PIDs recorded in the sector are read and decoded, it is checked whether there are three or more errors in the PID reading (S19).

When three or more errors are detected in the PID readout, the corresponding sector is classified as a defective sector, and the write operation is stopped. Next, by using the write signal processing unit 30 and the laser beam controller 20, the physical address of the newly detected defective sector is added to the PDL of the optical disc. The next target address is judged (S17), and the process from the step S13 is repeated.

In the case where the number of PID read errors of the target sector is less than 3, the sector is regarded as a non-defective sector. Accordingly, the data is written to the valid sector, and the next target address is judged (S21). In the repetition of the above steps, if it is judged in step S13 that the recording of all data is completed, the writing operation is terminated.

For the write operation, regardless of whether or not the data to be recorded is a/V data, a slipping replacement is performed with reference to the PDL.

Hereinafter, a detailed description will be given of a playback operation of the method of creating defect management information according to the present invention with reference to fig. 7 and 8.

If a reproduction command is input to the optical disc drive (S40), the read signal processing unit 40 judges whether the data to be reproduced is a/V data by decoding the data read from the optical pickup 10 (S41), and outputs the data to the PID detector 50 or the reproduction unit 60 according to the data type.

In the case of non a/V data, perfect playback is more important than continuous playback without delay. Therefore, the defective sectors corresponding to non-a/V data preferably use a linear replacement algorithm, as in the related art method, which is described in detail below.

After checking whether the playback is completed (S71), the data is read out from the target sector and played back (S73). At this time, it is checked by the PID detector 50 whether one or more sectors have three or more PID read errors (hereinafter, PID error sectors) in one ECC section (S75).

In the case where one or more PID error sectors exist in one ECC sector, the SDL manager 90 determines that the ECC sector containing the PID error sectors is a defective sector. The defective ECC sector is replaced with a non-defective replacement ECC sector in the spare area through a linear replacement process, and then corresponding data is recorded therein. At this time, information indicating that the defective ECC sector is replaced with the replacement ECC sector is stored in the SDL memory 70 c. Then, the next target sector is judged and located (S77).

Even without the PID error sector, the ECC sector is checked for the presence of newly grown defects. If the number of rows having 4 or more erroneous bytes in a row of 182 bytes per row in an ECC sector is 8 or more, the ECC sector is determined to be a bad sector (S79). The bad ECC block is replaced with the replacement ECC block by step S77.

If the ECC sector is judged as the valid ECC sector in the step S79, the data recorded on the ECC sector is reproduced and the next target sector is judged (S81). If it is determined in step S71 that there is no more data to be reproduced, the reproduction operation ends.

On the other hand, if it is judged in step S41 that the data to be reproduced is a/V data, a reproduction method according to the present invention which is different from the related art is performed. The following is a detailed description with reference to the flowchart of fig. 7.

First, it is checked whether the playback operation is completed (S43). If not, the data is read from the target sector and reproduced (S45). At this time, the PID detector 50 checks whether there are two or more errors in the PID readout of the target sector (S47). If there are two or more PID read errors, the T-PDL manager 80 judges the target sector as bad and stores its address in the T-PDL memory 70 b. Subsequently, the next target address is judged, and the optical pickup device moves to the next target sector (S49).

Even if the PID read error number is less than 2, it is judged whether the target sector is a bad sector by checking whether the number of lines having four or more error bytes in one sector is 4 or more (S51). The sector judged to be bad is also stored in the T-PDL memory 70 b. Next, the next target sector is determined (S49).

If a target sector is determined to be valid in step S51, the next sector is determined and the optical pickup moves to that sector (S53). Finally, if it is determined in step S43 that there is no more a/V data to be played back, the playback operation ends.

In short, if a sector in which non-A/V data is recorded is judged to be bad, the sector is replaced with an effective sector of the spare area so that the non-A/V data is reproduced without a read error in the next reproduction. On the other hand, in the sector in which a/V data is recorded, if the sector is judged to be bad, sector replacement is not performed to ensure real-time reproduction. But rather the address of the bad sector is kept in a reserved area of the disc that is isolated from the reserved areas of the PDL and SDL.

If the A/V data on the optical disk is repeatedly reproduced, the T-PDL memory 70b starts storing the address of the bad sector newly detected in the reproduction operation. When a user issues an erase command, the information about the new bad sector is written in a reserved area of the PDL on the optical disc. This is explained below with reference to the flowchart of fig. 9.

When an erase command is input to the optical disc drive (S101), the address manager 120 acquires a physical address of a sector where data to be erased is recorded (S107). Subsequently, the physical address stored in the T-PDL memory 70b is read out (S109), and the address acquired by the address manager 120 is compared with the address of the bad sector in the T-PDL memory (S111). If there is no matching address, an erase process is performed (S115). If there is at least one matching address, the matching address stored in the T-PDL memory 70b is moved to the PDL memory 70a through the bus (S113), and then the erasing process is performed (S115).

As shown in fig. 10, a reserved area for T-PDL on the optical disc may be placed within the data area, isolated from PDL and SDL; or in the DMA of the lead-in area, together with PDL and SDL. The former arrangement has an advantage of saving the existing defect processing information area for the PDL and the SDL. With this arrangement, it is preferable to reserve a space of the T-PDL at a position before or after the area where the program menu information is stored, which is repeatedly accessed in writing or playback operations. In the latter arrangement, the order of arrangement of the three types of defect lists in the DMA may be changed.

When the erase operation is completed and new data is rewritten to the disc, the bad sectors whose addresses are moved from the T-PDL memory 70b to the PDL memory 70a are skipped by the slipping replacement algorithm. As a result, data is prohibited from being written to the bad sector.

The foregoing is considered as illustrative and explanatory only of the preferred embodiments of the invention. Thus, variations, modifications and changes may be made without departing from the spirit and scope of the invention.

Claims (13)

1. A method of managing defect locations in a data storage medium, the data storage medium including primary defect management information identifying defect locations generated in at least one of a format mode, a recording mode, or a playback mode, the method comprising:

receiving a playback command for playing back data recorded at a predetermined position;

determining whether a defective area is found during a playback mode;

generating temporary defect management information for the defective area when it is determined that the defective area is found; and

the temporary defect management information is added to the primary defect management information based on a command.

2. The method of claim 1, wherein the data recorded at the predetermined position is real-time data.

3. The method of claim 1, wherein the generating step further comprises:

temporary defect management information of the defective area is recorded in a specific area of the data storage medium.

4. The method of claim 3, wherein the specific area is a lead-in area or a user data area in which primary defect management information is recorded.

5. The method of claim 1, wherein the command is a request signal for confirming whether the defective area is truly defective.

6. The method of claim 1, wherein the command is a request signal for clearing the defective area to re-record data on the defective area of the data storage medium.

7. The method of claim 1, wherein the adding step is performed after the playback mode is completed.

8. An apparatus for managing defect locations in a data storage medium, the data storage medium including primary defect management information identifying defect locations generated in at least one of a format mode, a recording mode, or a playback mode, the apparatus comprising:

a reading unit reading data recorded on a predetermined position by a control command;

a first manager that issues a control command to the reading unit, determines whether or not defect data is found in data output from the reading unit, and generates temporary defect management information of a defect location in which the defect data is found; and

a second manager for adding the temporary defect management information to the primary defect management information based on a command.

9. The apparatus of claim 8, wherein the data recorded at the predetermined position is real-time data.

10. The apparatus of claim 8, wherein the second manager is operable to record temporary defect management information of the defective location in a specific area of the data storage medium.

11. The apparatus of claim 10, wherein the specific area is a lead-in area or a user data area in which primary defect management information is recorded.

12. The apparatus of claim 8, wherein the second manager adds the temporary defect management information to the primary defect management information if the defect data is truly defective after the confirmation.

13. The apparatus of claim 8, wherein the control command is a command for a playback mode, and the second manager determines whether to add the temporary defect management information to the primary defect management information after completing the playback mode.