HK1089858B - Method of error correction coding, and apparatus for and method of recording data using the coding method - Google Patents

Description

Error correction encoding method, and apparatus and method for recording data using the same

Technical Field

The present invention relates to an error correction encoding method, and a method and apparatus for recording data using the error correction encoding method.

Background

The information recording medium includes: magnetic disks such as floppy disks and hard disks, magnetic tapes, semiconductor memory chips such as ROMs and RAMs, and optical disks such as CDs and DVDs.

The recording capacity of optical discs has rapidly increased with the development of semiconductor technology and signal processing technology, and the price of optical discs is relatively low.

Information recorded on the optical disc is recorded in units of blocks having a predetermined size. The block unit in which data is recorded is also a basic unit of Error Correction Coding (ECC). The size of an ECC block used in a conventional optical disc is typically 32 kbytes or 64 kbytes.

An optical disc has been attempted to be used as an information recording medium for simultaneously recording and/or reproducing both sound and images using a portable electronic device such as a video camera.

However, there are some disadvantages to using optical discs in portable electronic devices like video cameras. I.e. the size of the optical disc, typically 80mm or 120mm, is too large for a video camera and the power consumption is too high using a conventionally sized optical disc.

Therefore, in order to use an optical disc as an information recording medium of a portable electronic device, an optical disc having a smaller size but a higher recording density than a conventional optical disc is required.

When data is recorded and reproduced in a conventional size of an ECC block unit on a small-sized optical disc having a diameter of 30-50 mm, a problem may occur in error correction when the recorded data is reproduced.

For error correction coding in conventional DVDs, reed-solomon generated codes (RSPCs) are used. In the case of RSPC, the ECC block unit includes 416 recording frames corresponding to 32K user data. One synchronization frame includes 1488 slots (channel bits), one slot being 0.133 μm long. The length of a unit ECC block in the track direction is therefore 82,328.064 μm, which is equal to the circumference of a circle with a radius of 13.1 mm. Therefore, when an ECC block unit used in a conventional DVD is recorded within an area within a radius of 13.1mm, the ECC block unit will occupy more than one track. Therefore, when recording the conventional ECC block unit to a small-sized optical disc having a diameter of 30-50 mm, it is inevitable to record error correction data on two or more tracks.

Fig. 1 is a schematic diagram showing an inner circumferential area of a small-sized optical disc on which data having a conventional ECC block unit is recorded.

Referring to fig. 1, when ECC block units of 64 kbytes are recorded from an inner circumferential area to an outer circumferential area in a data recording area within a radius of 6mm from the center of a small-sized optical disc, conventional ECC block units are recorded from a point a to a point D in the area. That is, when recording ECC block units from the innermost circumferential area of a small-sized optical disc, the ECC block units are recorded on two tracks, thereby creating an overlapping area of ECC block units in the radial direction. If there is a scratch in a radial direction of an overlapping area on which a unit ECC block is recorded, a serious error may be generated in an ECC block unit, thereby significantly reducing error correction capability.

That is, if ECC block units are not recorded on only one track but are recorded on two tracks of a small-sized optical disc, if there is any defect such as a scratch on an inner circumferential area, the error correction capability of the recorded ECC block units is significantly reduced.

This problem occurs not only when RSPC is used as the ECC format, but also when long-distance codes (LDCs) are used.

According to U.S. patent No. 6,367,049, an ECC block unit includes 304 LDCs generated according to RSs (248, 216, 33) and 24 Burst Indicator Subcodes (BIS) generated according to RSs (62, 32, 33). The ECC block unit includes 64 kbytes of user data and 496 recording frames. Each recording frame includes: sync pattern, 152 bytes of ECC data, and 3 bytes of BIS.

When 8 bytes are modulated to 12 bytes according to a Run Length Limited (RLL) (1, 7) modulation method, if the number of sync patterns is 20, the length occupied by an ECC block is 937,440 × CBL according to the slot length (CBL) in the track direction and the ECC format.

The length of an ECC block disclosed in U.S. patent No. 6,367,049 is equal to the circumferential length of a circle of radius 149,274 × CBL. Since error correction corresponding to a length of 64 recording frames is possible according to the ECC format, the maximum error correction length is 120,960 × CBL.

Therefore, when the CBL is 0.100 μm, the radius of a circle having a circumference equal to the length of the ECC block is 14.93mm, and the maximum error correction length is about 12.10 mm.

When the CBL is 0.090 μm, the radius of a circle having a circumference equal to the length of the ECC block is 13.43mm, and the maximum error correction length is about 10.89 mm.

When the CBL is 0.080 μm, the radius of a circle having a circumference equal to the length of an ECC block is 11.94mm, and the maximum error correction length is about 9.68 mm.

When the CBL is 0.070 μm, the radius of a circle having a circumference equal to the length of an ECC block is 10.45mm, and the maximum error correction length is about 8.47 mm.

When the CBL is 0.060 μm, the radius of a circle having a circumference equal to the length of the ECC block is 8.96mm, and the maximum error correction length is about 7.26 mm.

In practice, an optical disc having a diameter of 120mm does not have an overlapping area of these ECC blocks because recording starts from a radius exceeding 20 mm. However, for a small-sized optical disc having a diameter of 30 to 50mm, the radius at which data starts to be recorded must be small to record as much data as possible.

In the case of applying the 64 kbyte ECC format disclosed in U.S. Pat. No. 6,367,049 to a small-sized optical disc in which data is recorded or stored from a radius of about 6-9 mm, and when CBL is greater than 0.060 μm, ECC block units are inevitably recorded on two or more tracks.

If the CBL is 0.070 μm and a recording frame includes 1890 slots, the length occupied by the recording frame is 132.3 μm. Therefore, a scratch of 2mm may affect about 16 consecutive recording frames. In this case, for the RS (248, 216, 33) code, an error of 8 bytes is caused, and when a scratch occurs on an overlapping area on which an ECC block unit is recorded on two tracks, an error of 16 bytes is caused.

Assume that erasure correction is performed for the scratch area and the byte error rate is 10^-3Then, a Block Error Rate (BER) when an 8-byte error or a 16-byte error occurs in an ECC block unit is as shown in table 1.

TABLE 1

	Error of 8 bytes	16 byte error
			When the scratch isBER at 1mm	7.8×10	2.5×10
BER when scratch is 2mm	2.5×10	1.1×10

Referring to table 1, the BER when a scratch occurs on an area in which ECC block units overlap on two tracks is greater than twice the BER of an error when a scratch of the same length occurs on an area in which ECC block units are in one track.

The length L of the ECC block unit occupying the recording medium length in the track direction is a multiple of the number of slot bits CBN of the ECC block, the minimum mark length MML according to the numerical aperture and the laser wavelength, and the slot bit length CBL defined by the modulation code. That is, L ═ CBN × MML × CBL.

The length of the ECC block can be reduced by increasing the density of recording lines (reducing the minimum mark length) and by reducing the length of the slot under the same modulation coding, thereby minimizing or removing an area overlapped by two or more tracks by an ECC block unit.

However, the effect of an error causing a problem such as a scratch or fingerprint increases in inverse proportion to the decrease in the slot length. As a result, even if the size of the error causing the problem is not changed, the effect of the error increases as the slot length decreases. That is, if the slot length is reduced, the maximum error correction length of the ECC block is also reduced. Therefore, as a way to recover the error correction capability of the ECC block on the overlap area, reducing the length of the slot is accompanied by a problem of reducing the maximum error correction length of the ECC block.

Therefore, in the case when the size of the ECC block is reduced at a fixed slot length (the minimum mark length is equal to the modulation code) and at the same parity rate (parity rate), the maximum error correction length may also be reduced. The maximum error correction length under the structure of the ECC format proposed in U.S. Pat. No. 6,367,049 is determined by adding parity of codewords existing in ECC block units and interleaving depth between the codewords. That is, since the ECC format is RS (248, 216, 33) code × 304, the maximum error correction byte is 9728.

As a result, the maximum error correction bytes will be reduced in addition to the parity of the codeword, since a reduction in the size of the ECC block maintaining the parity rate results in a reduction in the interleaving depth or a reduction in the amount of user data. Therefore, a reduction in error correction capability including the maximum error correction length will occur.

As described above, when the circumference of the area of the optical disc, to which ECC blocks are recorded or stored, is shorter than the length of a unit ECC block, the unit ECC block is recorded onto two or more tracks, thereby reducing the error correction capability, which results in reduced reproduction reliability.

A conventional optical disc has a structure of a recording area in which a lead-in area, a user data area, and a lead-out area are sequentially formed from an inner circumference area to an outer circumference area. In general, important information for reproducing data of an optical disc is recorded to an inner circumferential area corresponding to a lead-in area.

Therefore, the reduction of the error correction capability of the ECC block unit recorded in the inner circumferential area becomes a serious problem.

Disclosure of Invention

Technical solution

The present invention provides an error correction encoding method that prevents ECC block units from being recorded on two or more tracks of a small-sized optical disc and improves error correction capability.

The present invention also provides an apparatus and method for recording data using the encoding method.

Advantageous effects

As described above, according to embodiments of the present invention, an error correction encoding method, a method of recording data, and an apparatus of recording data can prevent ECC block units from being recorded on more than two tracks of a small-sized optical disc, thereby improving error correction capability.

Furthermore, conventional hardware can be used without major modification when increasing the parity rate by reducing the length of the user data and maintaining the parity length of conventional reed-solomon encoding.

Drawings

These and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic diagram of an inner circumferential area of a small-sized optical disc to which data is recorded in units of conventional ECC blocks;

FIG. 2 is a format of an LDC block according to an embodiment of the present invention;

FIG. 3 is a format of an embodiment of the structure of the LDC block depicted in FIG. 2;

fig. 4 is a format of an LDC block after interleaving the LDC block described in fig. 3 in a predetermined method;

fig. 5 is a format of a structure of a BIS block according to an embodiment of the present invention;

fig. 6 is a format of the BIS depicted in fig. 5 after interleaving;

fig. 7 is a format of an ECC block generated by combining the LDC block described in fig. 4 and the BIS block described in fig. 6 with a sync pattern;

fig. 8 is a block diagram of an apparatus for recording and reproducing data according to an embodiment of the present invention; and

fig. 9 is a flowchart illustrating a method of recording data according to an embodiment of the present invention.

Best mode for carrying out the invention

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

According to an aspect of the present invention, there is provided an error correction encoding method including: generating (184, 152, 32, 216) an LDC block with 32K bytes of user data; generating a BIS block indicating a location of an occurring error group; and generating an ECC block by combining a predetermined amount of BIS block data and an LDC block, wherein different portions of the BIS block are separated by one or more portions of the LDC block by a predetermined distance.

According to another aspect of the present invention, there is provided a data recording apparatus comprising: an optical head; a codec which generates a plurality of codewords by error correction coding a predetermined amount of data according to a predetermined method; and a control unit controlling the optical head to record data including the plurality of codewords in a recording unit having a length shorter than a predetermined track in an inner circumferential area of the small-sized optical disc.

The codec may perform error correction encoding according to a reed-solomon encoding method in which a parity byte P is added to an input data byte D, and may perform error correction encoding according to a determined parity rate P/(D + P) for complementing a reduction in error correction capability caused by a short length of a recording unit.

The parity rate can be determined by decreasing the input data bytes D and increasing the parity bytes P.

According to an embodiment of the present invention, there is provided a method of recording data to a small-sized optical disc, including: forming a plurality of codewords by error correction coding a predetermined amount of data according to a predetermined method; and recording data including the plurality of codewords to the small-sized optical disc in a recording unit having a length shorter than a predetermined track of an inner circumferential area of the small-sized optical disc.

The error correction coding may be performed according to a reed-solomon coding method in which the parity bytes P are added to the input data bytes D.

The step of forming a plurality of codewords by error correction coding may further include determining a parity rate P/(D + P) for complementing a reduction in error correction capability caused by the short length of the recording unit.

The step of forming a plurality of codewords by error correction coding may increase the parity rate by decreasing the input data bytes D and increasing the parity bytes P.

Modes for carrying out the invention

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.

As described above, when data is recorded to a small-sized optical disc having a diameter of about 30-50 mm, in which a bit length of a groove (CBL) is between 0.060 μm and 0.133 μm and a start radius of data recording is 6 mm-9 mm, according to an ECC format having 64 kbytes of user data disclosed in U.S. Pat. No. 6,367,049, an overlapping area of ECC blocks inevitably exists in a radial direction.

In the present invention, the user data size within an ECC block is reduced to 32 kbytes to avoid overlap of ECC blocks in the radial direction. In addition, the parity rate of the data is increased to supplement the reduced error correction capability. The parity rate of data is expressed as the following equation.

Equation 1

Parity rate P/(D + P)

In equation 1, D denotes a byte size of user data, and P denotes a byte size of parity.

Considering that a possible slot length (CBL) is 0.060 by a current modulation code and optical characteristics such as a numerical aperture and a laser wavelength, if a 64 kbyte ECC format disclosed in U.S. Pat. No. 6,367,049 is modified into a 32 kbyte ECC format while maintaining a parity rate of an RS (248, 216, 33) code x 152 or an RS (124, 108, 17) code x 304 in the same recording frame, an ECC block of a size of 32 kbytes has the same length as a circumference of a circle having a radius of about 4.48 mm. Therefore, if the starting radius of the recorded data is 6-9 mm, there will be no overlapping area of the ECC block in the radial direction, but the maximum error correction length is reduced to 3.63mm, thereby considerably reducing the error correction capability.

In order to prevent a reduction in error correction capability, it is necessary to avoid overlapping of ECC blocks in the data recording area in the radial direction, and in order to extend the maximum error correction length, it is necessary to increase data parity. However, a full modification of the ECC format is not desirable.

Fig. 2 is a format of an LDC block according to an embodiment of the present invention. Referring to fig. 2, N denotes a length of an RS code, K denotes a user data length of the RS code, P denotes a parity length of the RS code, and C NUM denotes the number of RS codes.

As described above, in the case where (N, K, P, C _ NUM) ═ 248, 216, 32, 152 or (N, K, P, C _ NUM) ═ 124, 108, 16, 304, C _ NUM in the ECC format of U.S. Pat. No. 6,367,049 is halved, or N, K and P are reduced to 32 kbytes. In this case, when the CBL is 0.060 μm, the maximum error correction length is only 3.63 mm. Therefore, since it is likely that reliability problems will occur in data reproduction, the data parity rate needs to be appropriately increased to improve the error correction capability.

The ECC format of the present invention must satisfy the following conditions.

First, the size of an ECC block, which is a basic unit for recording and reproducing data, must be set to 32 kbytes in this example to prevent the ECC block from overlapping two or more tracks in the radial direction. That is, since 4 bytes of Error Detection Code (EDC) is added to each 2 kbytes (2048 bytes) long sector, the number of bytes other than parity in the LDC block is 32,832 bytes.

Second, BIS must be considered. The BIS must be large enough to store the physical sector address and control data.

Third, the ECC format must have a maximum error correction length as long as possible.

Fourth, a storage capacity according to data efficiency must be considered.

Fifth, the total number of recording frames must be a multiple of 8 or 16 when forming an ECC block. In the case of a DVD, an ECC block contains 16 physical sectors, each having a data ID that allows quick access to the ECC block or physical sector when reproduced.

Sixth, it is preferable that the number of parities of the RS code is below 32 and the length of the RS code should be as long as possible in consideration of the hardware load of the error correction system of the RS code.

Regarding the first condition, since the ECC format includes an LDC and a BIS, which is different from the RSPC structure of the DVD, address information for accessing a physical sector has been stored in the BIS as disclosed in U.S. patent No. 6,367,049. Since data for controlling the user data may be stored in the control data, no additional data is necessary except for the user data and the EDC.

Regarding the second condition, a physical sector or a space for storing control information for user data needs to be accessed.

Regarding the third and fourth conditions, when the maximum error correction length increases, data efficiency is reduced due to a low rate of user data, so that the storage capacity of the entire medium decreases. However, the storage capacity is more meaningful when the error correction capability of the ECC format exceeds a predetermined level. In other words, even though the storage capacity may be large, it is not useful if the data is unreliable. After ensuring a sufficient level of error correction capability, the storage capacity of the medium may be meaningfully considered.

As for the fifth condition, it is preferable, though not necessary, that the physical sectors are regularly arranged on the medium at appropriate intervals. Since the host and the drive transmit and receive user data in a size of 2 kbytes, and in consideration of the fact that one block has a size of 32 kbytes, the number of recording frames within one ECC block needs to be a multiple of 16.

Regarding the sixth condition, the hardware load of the error correction system of the RS code is determined by the parity number.

As the number of parities increases, the number of errors that can be corrected in the codeword increases. However, the load of the hardware also increases by the same order of magnitude. In view of the conventional technique, it is desirable to have less than 32 parities. As the codewords of the same parity rate become longer, the error correction capability increases.

Fig. 3 is a format of the structure of the LDC block depicted in fig. 2 according to an embodiment of the present invention.

Referring to fig. 3, the structure of the LDC block is (184, 152, 32, 216). That is, N is 184, K is 152, P is 32, and C _ NUM is 216. Thus, a 32 kbyte sized error correction LDC block comprises 216 (184, 152, 32) LDCs.

Generally, since the size of a data unit for communication between a host and a disc drive is 2 kbytes (2048 bytes) per sector, the ECC format adds 4 bytes of Error Detection Code (EDC) to 2 kbytes of user data. The disc drive adds 4 bytes of EDC when encoding to check whether error correction has been completed after reading data from the disc and correcting errors. As shown in fig. 3, 2052 bytes including 2 kbytes of user data and 4 bytes of EDC correspond to 13.5 columns.

Fig. 4 is a format of an LDC block after interleaving the LDC block described in fig. 3 in a predetermined method.

There are several interleaving methods. Fig. 4 shows block interleaving according to the methods described in fig. 10 and 12 in U.S. patent No. 6,367,049. The first method of interleaving described in fig. 10 of U.S. patent No. 6,367,049 is a method of inserting byte information of odd columns between byte information of even columns. A second method of interleaving shown in fig. 12 of U.S. patent No. 6,367,049 is a method of moving line information in a line direction after the first interleaving. In the above u.s. patent, the shift value is 3, but the present embodiment may use a shift value of 1 or 7 that is relatively prime to 108, thereby maximizing the period.

Fig. 5 is a format of a structure of a BIS block according to an embodiment of the present invention. The BIS block has a structure of (46, K, P, C _ NUM), and this embodiment is summarized in table 2.

TABLE 2

K	P	C NUM	Physical address	Control data
					14	32	16	16 x 9 bytes	16 x 5 bytes
14	32	24	16 x 9 bytes	16 x 12 bytes
					22	24	16	16 x 9 bytes	16 x 13 bytes
22	24	24	16 x 9 bytes	16 x 24 bytes

Fig. 6 is a format of BIS blocks of the first and third structures in table 2 after interleaving according to the interleaving method described in fig. 14A of U.S. patent No. 6,367,049. In other words, since C _ NUM is 16, C _ NUM can be divided into 8 parts by binding two codewords as shown in fig. 5 and then interleaved according to the interleaving method described in fig. 14A of U.S. Pat. No. 6,367,049. Although not shown in the drawings, BIS blocks of the second and fourth structures are performed in the same manner as above, except that the number of rows is changed to 3 in fig. 6.

Fig. 7 is a format of an ECC block created by combining the LDC block of fig. 4 and the BIS block of fig. 6 with a sync pattern.

Referring to fig. 7, the ECC block includes 368 recording frames. Each recording frame includes: sync pattern, LDC of 108 bytes, and BIS of 2 bytes. The ECC block includes 16 physical sectors, and 23 recording frames are recorded to each physical sector.

Each BIS byte includes addresses of physical sectors such that 16 physical sector addresses separated by a predetermined distance are recorded to a single ECC block.

When C _ NUM of the BIS block in fig. 5 is 24, then the number of rows in fig. 6 is 3 and each row of the ECC block in fig. 7 has a structure in which 4 lds of 27 bytes and 3 BIS of 1 byte are inserted between LDCs of 27 bytes.

So far, the LDC block having the structure of (184, 152, 32, 216) described in fig. 3 has been described. The structure of the LDC block according to the present invention may further include a structure such as (132, 108, 24, 304), (136, 108, 28, 304), or (140, 108, 32, 304).

When the structure of the LDC block is (132, 108, 24, 304), the structure has a BIS block of (33, 17, 16, 24) and can form an ECC block in which 264 recording frames are recorded to 8 physical sectors.

When the structure of the LDC block is (136, 108, 28, 304), the structure has a BIS block of (34, 18, 16, 24) and may form an ECC block in which 272 recording frames are recorded to 8 physical sectors.

When the structure of the LDC block is (140, 108, 32, 304), the structure has a BIS block of (35, 19, 16, 24) and can form an ECC block in which 280 recording frames are recorded to 8 physical sectors.

In a similar manner to the structure shown in table 2, the (N, K, P, C _ NUM) values of the BIS blocks in the above embodiments may also be modified to fit the structure of the recording frame in the ECC block and the number of physical sectors of a predetermined size, in addition to those discussed above as example values.

In the ECC block of fig. 7, if the modulation coding modulates the RLL (1, 7) level of 8 bits to 12 bits and the length of the sync pattern length is 20 bits, the ECC block does not overlap in the radial direction after the recording radius of 6mm when the CBL is less than 0.070 μm.

The maximum error correction length and data efficiency of different embodiments of ECC blocks according to the present invention and the CBL of conventional ECC blocks are summarized in table 3.

TABLE 3

Referring to table 3, as shown in fig. 7, the first embodiment has LDC blocks of (184, 152, 32, 216) and BIS blocks of (46, 14, 32, 16), and is an ECC block in which 368 recording frames are recorded to 16 physical sectors. The second embodiment has an LDC block of (132, 108, 24, 304) and a BIS block of (33, 17, 16, 24), and is an ECC block in which 264 recording frames are recorded to 8 physical sectors. The third embodiment has an LDC block of (136, 108, 28, 304) and a BIS block of (34, 18, 16, 24), and is an ECC block in which 272 recording frames are recorded to 8 physical sectors. The fourth embodiment has an LDC block of (140, 108, 32, 304) and a BIS block of (35, 19, 16, 24), and is an ECC block in which 280 recording frames are recorded to 8 physical sectors. The conventional art refers to the ECC block of U.S. patent No. 6,367,049.

Assuming that erasure correction is performed on a portion where scratches occur, a block error rate according to the conventional art and a Block Error Rate (BER) according to the present invention are shown in tables 4 to 6. BER is calculated according to equations 2 and 3 below.

Equation 2

Equation 3

Where CER denotes the codeword error rate, e denotes the number of erasures, and p denotes the byte error rate.

TABLE 4

	Example 1	Example 2	Example 3	Conventional technique
					Parity check	32	24	28	32
p	0.001	0.001	0.001	0.001
					e	14	10	10	10
N	184	132	136	248
					C_NUM	216	304	304	304
BER	7.9×10	2.6×10	5.3×10	1.3×10

Table 4 shows the BER when a scratch of 2.268mm occurred in each case.

TABLE 5

	Example 1	Example 2	Example 3	Conventional technique
					Parity check	32	24	28	32

p	0.001	0.001	0.001	0.001
					e	7	5	5	5
N	184	132	136	248
					C_NUM	216	304	304	304
BER	3.2×10	5.7×10	8.6×10	4.8×10

Table 5 shows the BER when a scratch of 1.134mm occurs in each case.

TABLE 6

	Example 1	Example 2	Example 3	Conventional technique
					Parity check	32	24	28	32
p	0.001	0.001	0.001	0.001
					e	0	0	0	0
N	184	132	136	248
					C_NUM	216	304	304	304
BER	1.3×10	3.2×10	3.4×10	2.8×10

Table 6 shows the BER when there was no scratch in each case.

The first to third embodiments and the conventional technique in tables 4 to 6 indicate the first to third embodiments and the conventional technique in table 3, respectively.

When compared with the conventional art, the data efficiency and error correction capability of the first and third embodiments are most desirable in the case where the CBL is 0.06 μm.

Hereinafter, a data recording and/or reproducing apparatus according to the present invention will be described.

Fig. 8 is a block diagram 200 of an apparatus for recording and reproducing data according to an embodiment of the present invention.

Referring to fig. 8, the apparatus 200 for recording and/or reproducing data includes: an optical head 210, a codec 220, a disc information storage unit 240, a control unit 260, a data input interface unit 270, and a user interface unit 280.

The optical head 210 records data to the small-sized optical disc 100 or reads data recorded on the small-sized optical disc 100 in response to control by the control unit 260. The small-sized optical disc 100 is an optical disc having a radius of the innermost circumference of 6 mm.

The codec 220 performs error correction coding on data to be recorded on the small-sized optical disc 100 according to an embodiment of the present invention, or decodes data read from the small-sized optical disc 100 in reverse processing of the coding.

The disc information storage unit 240 stores information related to the small-sized optical disc 100.

The codec 220 generates the LDC block by encoding user data according to various ECC formats as shown in the first to fourth embodiments of the present invention. The codec 220 calculates the parity according to a predetermined method. The method of calculating the parity may be a conventional method, and thus a detailed description thereof will be omitted.

Further, the codec 200 generates a BIS block to indicate a location of an error when reproducing data, and generates an ECC block by arranging LDC data and BIS data at a predetermined distance as described in fig. 7. The codec 220 finally generates an ECC block to be recorded to the small-sized optical disc 100 and outputs it to the optical head 210.

The disc information storage unit 240 stores information about the small-sized optical disc 100. The information includes a data area structure or a data recording algorithm of the small-sized optical disc 100.

The control unit 260 controls the codec 220 and the optical head 210 to record data to the small-sized optical disc 100. Specifically, the control unit 260 controls the optical head 210 to record the data output from the codec 220 to the small-sized optical disc 100 in a recording unit shorter than the length of a predetermined track of the inner circumferential area of the small-sized optical disc 100.

The input data interface unit 270 transmits the input data to be recorded to the small-sized optical disc 100 to the control unit 260.

The user interface unit 280 transmits a command for recording data to the small-sized optical disc 100, which is input from the user, to the control unit 260.

Referring to the structure of the data recording/reproducing device 200 as described above, a method of recording data to the small-sized optical disc 100 according to an embodiment of the present invention will now be described.

Fig. 9 is a flowchart of a method of recording data according to an embodiment of the present invention.

In order to record data to the small-sized optical disc 100, the size of the ECC block is reduced. However, to supplement the reduction of the error correction capability due to the reduction of the ECC block size, a parity rate of reed-solomon encoding for error correction is determined (operation 410). By employing an LDC block having a structure of (184, 152, 32, 216), the parity rate in embodiments of the present invention is improved to 32/184. Information required for error correction including the determined parity rate is pre-recorded in the codec 220.

The codec 220 generates a plurality of codewords by error correction coding a predetermined amount of input data, such as 32 kbytes of user data, according to the determined Solomon-coded parity rate (operation 430).

Even though not described in the flowchart, the codec 220 generates a BIS block to indicate a location of an error when reproducing data, and generates an ECC block by arranging LDC data and BIS data at a predetermined distance as described in fig. 7. The codec 220 finally outputs the ECC block to be recorded to the small-sized optical disc 100 to the optical head 210.

On the other hand, various ECC formats other than the LDC block of (184, 152, 32, 216) may be formed as in the second to fourth embodiments of the present invention.

The optical head 210 receives data including a plurality of codewords from the codec 220 in response to the control of the control unit 260 and records the data to the small-sized optical disc 100 in a recording unit having a length shorter than the length of a predetermined track of the inner circumferential area of the small-sized optical disc 100.

The present invention can also be embodied as computer readable codes on a computer readable recording medium. The computer readable recording medium is any data storage device that can store data which can be thereafter read by a computer system. Examples of the computer readable recording medium include read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and carrier waves. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims (8)

1. A method of recording data, the method comprising:

forming a plurality of codewords by error correction coding a predetermined amount of data according to a predetermined method; and

data including the plurality of codewords is recorded to the small-sized optical disc in a recording unit having a length shorter than a predetermined track of an inner circumferential area of the small-sized optical disc.

2. The method of claim 1, wherein the error correction coding is performed according to a reed-solomon coding method in which parity bytes P are added to input data bytes D.

3. The method of claim 2, wherein the forming of the plurality of codewords by error correction coding further comprises determining a parity rate P/(D + P) for complementing a reduction in error correction capability caused by the length of the recording unit.

4. The method of claim 3, wherein the step of forming the plurality of codewords by error correction coding increases the parity rate by decreasing input data bytes D and increasing parity bytes P.

5. A data recording apparatus comprising:

an optical head;

a codec generating a plurality of codewords by error correction coding a predetermined amount of input data according to a predetermined method; and

and a control unit controlling the optical head to record data including the plurality of codewords in a recording unit having a length shorter than a predetermined track in an inner circumferential area of the small-sized optical disc.

6. The data recording apparatus of claim 5, wherein the codec performs the error correction coding according to a reed-solomon coding method in which the parity bytes P are added to the input data bytes D.

7. The data recording apparatus as claimed in claim 6, wherein the codec performs error correction coding according to a determined parity rate P/(D + P) for complementing a reduction in error correction capability caused by the length of the recording unit.

8. The data recording apparatus of claim 7, wherein the parity rate is determined by decreasing input data bytes D and increasing parity bytes P.