JP2839489B2 - Information recording and playback method - Google Patents

Description

The present invention relates to an information recording / reproducing method for recording / reproducing information on / from an information recording medium. (Conventional technology) CAV (Constant Angula)
r Velocity method and CLV (Constant Linear Velocit)
y) method. In the CAV method, the rotation speed of the optical disk medium is kept constant, and recording or reproduction is performed at a constant bit rate. Therefore, it is not necessary to change the number of revolutions of the rotary motor during a seek operation for positioning the light spot on a predetermined block, and a high-speed seek operation is possible, but the recording capacity per track of the optical disc medium is reduced. Since it is constant regardless of the position, the total storage capacity of the optical disk medium is smaller than that of the CLV method. In the case of the CLV system, recording or reproduction is performed at a constant bit rate while changing the rotation speed of the rotation motor so as to be inversely proportional to the radial direction of the optical disk medium. For this reason, the storage capacity per track of the optical disk medium increases in proportion to the radius, and the total storage capacity of the optical disk medium is CAV.
1.5 times the system. However, it is necessary to change the rotation speed of the rotary motor during the seek operation, so that the seek operation time is delayed. MCAV (Modified Constant Angular Veloci) is a new recording method that solves the above-mentioned drawbacks of the CAV method and CLV method.
ty) method has been developed. The MCAV system is a system in which recording or reproduction is performed while changing the bit rate in proportion to the radial position of the optical disk medium while keeping the rotation speed of the optical disk medium constant. Therefore, it is not necessary to change the rotation speed of the rotary motor during the seek operation, and a high-speed seek operation can be performed. Since the storage capacity per track of the optical disk medium increases in proportion to the radius, the total storage capacity of the optical disk medium is the same as that of the CLV system. (Problems to be Solved by the Invention) The optical disk medium used in the MCAV system is divided into a plurality of blocks along a track, and an ID is provided at the beginning of each block.
Information is formed in advance in the manufacture of the optical disk medium and is so-called preformatted. This ID information is detected at the time of data recording or reproduction, and data recording or reproduction is performed on a data area provided after the ID information.
When recording or reproduction is performed by the MCAV method using an optical disk medium having such a format, the time required for a light beam to scan one block is not constant, but becomes shorter as it goes to the outer peripheral portion of the disk. That is, the relative speed between the optical disk medium and the pickup head is increased in the outer peripheral portion, and the situation where ID information cannot be detected occurs. Also, when manufacturing, using or aging of optical disk media,
If the optical disc medium is scratched or dusty, the ID information cannot be detected. For this reason, data recording or reproduction is hindered. In particular, ID information can be detected during recording, and even if data can be recorded in the data area after the ID area,
If a situation where information cannot be detected occurs, the recorded data cannot be reproduced, which causes a problem in the reliability of the device. Accordingly, an object of the present invention is to provide an information recording medium that prevents ID information detection errors. [Structure of the Invention] (Means for Solving the Problems) According to the present invention, a plurality of blocks each storing a block number are stored.
Prepare an information recording medium having a plurality of blocks consisting of a header area in which ID information is continuously provided and a data recording / reproducing area following the header area. Reproduction of information is performed on condition that a predetermined number of ID information of the ID information is searched from the header area, and when information is recorded in the data recording / reproduction area, the information is reproduced more than the predetermined number of ID information at the time of information reproduction. There is provided an information recording / reproducing method for recording information on condition that a search is performed from a large number of ID information header areas. (Operation) By making the ID information detection conditions stricter at the time of recording than at the time of reproduction, it is possible to increase the reliability of recording and avoid the occurrence of a reproduction error. (Embodiment) FIG. 2 shows an optical disk medium 1 used in the optical disk apparatus of the present invention. For example, in the case of the 5-inch optical disk medium 1, 20,000 tracks are provided in a radius of 29 to 61 mm, and about 400,000 blocks are formed in the MCAV system.
These blocks are formed continuously on the optical disc 1 in a spiral shape. The number of blocks per track from the innermost track to the outermost track varies from 14 to 28. The bit rate is 165 within a radius of 30 to 60 mm.
Switching is performed in 114 steps for each track, and the rate of change in bit rate between adjacent track stages is designed to be within 1%. At the start position of each block, a block header A is provided, for example, when the optical disk medium 1 is manufactured. Each block is a basic unit for recording information, and a minimum of 14
It consists of 35 bytes and is formatted as shown in FIG. That is, it has a preformat section D1 and a data section D2 that constitute the header A. Preformat section D1
Is composed of, for example, 48 bytes, and has a 16-byte preamble VFO followed by four ID area IDs (each ID is composed of 8 bytes including 1-byte synchronization information). Each ID area ID has a block number (No.), ID number (I
D), CRC and DMY are stored. The data part has a recorded flag (1
6 bytes), VFO (16 bytes), data, ECC, resynchronization code (1306 bytes), PO (2 bytes), postfield (POST FIELD: 32 bytes), block gap (GAP: 15
Byte). As shown in FIG. 2, the optical disc medium 1 records defect management information on the inner periphery of the recording area 1a and is used as a substitute for the defect area.
Is provided. A user area (user recording area) b is provided as a recording area used by the user. As shown in the circuit shown in FIG. 3, the optical disk medium 1 is read and written by an optical head 2. As is well known, the optical head 2 includes a semiconductor laser, an optical system, a tracking system, a focusing system, and a photoelectric sensor.
The output of the optical head 2 is connected to a reproduction signal binarization circuit 4 via a reproduction signal amplification circuit 3. Reproduction signal binarization circuit 4
Converts a reproduction signal into a digital signal (2-7 code modulation signal). The drive input section of the optical head 2 is connected to a laser drive circuit 5 for receiving a modulation signal from the modulation circuit 6 and driving the semiconductor laser of the optical head 2. The output of the reproduction signal binarization circuit 4 is connected to a reproduction synchronous clock extraction circuit 7, a demodulation circuit 8, and an address mark detection circuit 9. The reproduction synchronous clock extracting circuit 7 is a circuit for generating a demodulated clock from the 2-7 code modulated signal, and the demodulating circuit 8 is a circuit for demodulating the 2-7 code modulated signal into an NRZ signal by the demodulated clock. The address mark detection circuit 9 is a circuit that is provided immediately before the ID information and detects an address mark including an irregular pattern that deviates from the 2-7 code conversion rule. The output of the demodulation circuit 8 is connected to a recorded flag detection circuit 10, an ID shift register 11, a CRC detection circuit 12, and a recording / reproduction switching circuit 15. The output of the CRC detection circuit 12 is connected to the ID detection timing circuit 13 together with the output of the address mark detection circuit 9. The output of the ID detection timing circuit 13 is
It is connected to the ID shift register 11, the CRC detection circuit 12, and the timing signal input terminal of the comparator 16. The output of the ID shift register 11 is connected to an ID comparator 16 and an ID counter 17. The output of the ID comparator 16 and the output of the ID counter 17 are connected to a recording / reproduction timing circuit 18. The output of the recording / reproduction timing circuit 18 is a laser drive circuit 5, a modulation circuit 6, a recording / reproduction switching circuit
15 and the ID counter 17. The recorded flag detection circuit 10 is connected to the control circuit 30 together with the ID shift register 11. The output of the control circuit 30 is connected to other input terminals of the recording / reproduction ID register 14 and the recording / reproduction timing circuit 18.
Postfield content register 19, CRC generation circuit, postamble pattern generation circuit 21, resynchronization code pattern generation circuit 22, VFO pattern generation circuit 23, address mark pattern generation circuit 24, recorded flag pattern generation circuit 2
5. The data buffer 26 and the error correction code addition / error correction circuit 27 are connected to the recording / reproduction switching circuit 15. Data buffer 2 via external interface 29
6. The data transfer circuit 28 and the control circuit 30 are connected to an external device. In the above apparatus, when the optical disk medium 1 is rotated at, for example, 925 rpm by a rotation motor (not shown) and the optical head 2 is driven by the laser driving circuit 5, the laser spot from the optical head 2 causes the guide groove of the optical disk medium to be guided. Is tracked. Recording and reproduction are performed in block units, and a seek operation is performed to position the light spot in a predetermined block. In this seek operation, the reproduction signal obtained from the optical head 2 is amplified by the reproduction signal amplifier circuit 3 and is reproduced by the reproduction signal binarization circuit 4 to obtain a 2-bit signal.
It is converted into a 7-code modulated digital signal. The digital signal is demodulated into an NRZ signal by the demodulation circuit 8 in synchronization with the synchronization clock extracted from the reproduction signal by the reproduction synchronization clock extraction circuit 7. When the digital reproduction signal is input to the address mark detection circuit 9 and the address mark immediately before the ID information is detected, the ID detection operation timing circuit 13 is driven. ID detection operation timing circuit 13 is CRC
Although the signal is received from the detection circuit 12, the CRC detection circuit 1
2 is CRC using the CRC set for ID and number of times
Perform a check. If the result of this CRC check is determined to be incorrect, the ID information is discarded. If the ID check result is correct, a signal is output to the ID detection operation timing circuit 13. The ID detection operation timing circuit 13 inputs an ID detection operation timing signal to the ID shift register 7. In response to this signal, the ID shift register 7 transfers the count data of the ID information included in the stored content to the count counter 17 and also stores the stored content in the control circuit 30.
Transfer to The control circuit 30 recognizes the current position of the light spot from the ID information and moves the light spot to the target block of the target track by driving the optical head and the driving means (not shown) for driving the objective lens in the optical head. Let it. The control circuit 30 determines that the input ID information is the ID of the target block.
The ID information of the target block is set in the recording / reproducing ID register 14 in order to confirm whether the information is information or not, and the comparator 16 is used to compare the set ID information with the input ID information of the ID shift register 11. input. When an error-free signal is output from the CRC detection circuit 12 and the comparator 16 outputs a signal indicating that the ID information of the target block matches the read ID information, the recording / reproduction operation timing circuit 18 outputs a recording / reproduction operation. Are input to the laser drive circuit 5, the modulation circuit 6, the recording / reproduction switching circuit 15, and the ID counter 16. The operation of the recording / reproducing operation timing circuit 18 is preset by the control circuit 30. Therefore, the CRC detection circuit 12 and the ID
Even if the operation signal is input from the comparator 16, if the control circuit 30 has set the state in which the operation is prohibited, the recording / reproduction operation timing circuit 18 does not operate. When the seek operation as described above, that is, the operation of moving the light spot to the target block or recording or reproducing data in the target block, it is necessary to correctly detect the ID information. An error may occur in ID information detection due to contamination in the inside, deterioration of the recording area due to aging, and the like. Generally, the error rate of an optical disk is 1 × 10 ^-5 to 1 × 10 ^-4
This is about error / bit. Therefore, the probability that the ID information composed of 8 bytes (= 64 bits) contains an error is 64.
The error rate is about × 1 × 10 ⁻⁵ to 64 × 1 × 10 ^−4, which is much higher than the error occurrence rate of 10 ⁻¹² errors / byte after the data part corrected by the error correction method. Therefore, in the present invention, the ID information is multiplexed four times and recorded on the optical disk medium 1. By recording ID information in quadruplicate, the occurrence rate of ID detection errors is considerably reduced. The following table shows the error occurrence rates for three examples where the number of ID information is 4, 3, and 2. As shown in the above table, when each block is provided with four pieces of ID information, and if the probability that an error is mixed in one ID area is 5 × 10 ⁻³ , the four pieces of ID information are The probability of not being able to detect even one is (5 × 10 ⁻³ ) ⁴ = 6.25 × 10 ⁻¹⁰ . This value is equal to or less than the probability that a data error is mixed in one blog, ie, 10 ⁻⁹ to 10 ^−10, and a practically sufficient read rate can be obtained by quadrupling the ID information. The probability that the three pieces of ID information are defective is 0.19 blocks in terms of the number of blocks per surface, which is practically acceptable. When three ID information are provided in one block, two ID information
The probability that no ID information can be detected is 29.14 blocks per side, and the probability that none of the three pieces of ID information can be detected is 0.05 blocks per side. Within this range, there is no practical problem. However, when only two pieces of ID information are provided in one block, the error occurrence rate becomes considerably large at 3886.7 / surface / thus, it is necessary to provide three or more pieces of ID information in one block. However, when the ID information is increased, the total storage capacity of the data decreases. Therefore, it is preferable to provide the ID information in a range of 3 to 5 pieces. In the detection of the ID information described above, in particular, as described above, in order to reliably detect the ID information during reproduction, it is necessary to perform the
The ID detection conditions need to be stricter than during playback. Therefore, at the time of recording, it is necessary to detect at least two pieces of ID information. If two pieces of ID information cannot be detected, recording of data in the block is prohibited, and data is stored in the alternative area a as necessary. An alternative process of recording is performed. The above prohibition and alternative processing are controlled by the control circuit 30. That is, when the optical disc apparatus is set to the recording mode, the correctly detected ID information of the four pieces of ID information is sequentially input to the control circuit 30 via the ID shift register 11. When receiving two or more pieces of ID information, the control circuit 30 inputs a signal instructing the start of the recording operation to the recording / reproduction operation timing circuit 18. The recording / reproducing operation timing circuit 18 inputs a control signal for recording to the recording / reproducing switching circuit 15. The recording / reproducing switching circuit 15 responds to the control signal and generates a postamble pattern generating circuit 21, a reproducing synchronous code pattern generating circuit 22, a VFO pattern generating circuit 23.
And the data in the data buffer 26 is selectively guided to the modulation circuit 6. The data buffer 26 stores the recording data from the data transfer circuit 28 and adds an error correction code / error correction circuit.
27 adds an error correction code to the recorded data. The error correction code addition / error correction circuit 27 performs a strict check by performing correction with a weak correction capability in the case of read-after-write at the time of recording, so that correction can be performed with a normal error correction capability during reproduction. The recording / reproducing switching circuit 15 receives the ID number counter 17, and the ID number counter 17 is loaded with the ID number of the last detected ID information. The ID number value is the last detected ID information. This corresponds to the distance (for example, the number of bytes) from the recording position to the data recording start position. Therefore, the data recording start position can be determined from the number of times. When the ID number counter 17 counts up to the number of times corresponding to the data recording start position, a recording timing signal is supplied to the switching circuit 15. At this time, the data of the postamble pattern generation circuit 21, the resynchronization code pattern generation circuit 22, the VFO pattern generation circuit 23, and the data buffer 26 are input to the modulation circuit 6, and the laser driving circuit 5 operates according to the modulation signal. The second semiconductor laser is driven. Data is written from a data recording start position of a predetermined block of the optical disk medium 1 by a laser beam generated from a semiconductor laser. When the writing of data to the data section is completed, the operation proceeds to read-after-write. That is, when the optical spot reaches the same block after the optical disk medium 1 makes a round, the ID information is read, the start position of the recorded flag area is determined, and the recorded flag output from the recorded flag pattern generation circuit 25 is recorded. Is written in the recorded flag area. Further, the start position of the post-field is determined from the ID information, and data from the ID number counter 17, the CRC generation circuit 20, and the address mark pattern generation circuit 24 are written in this post-field. Note that the postfield content register 19 is
The data is input. By writing the recorded flag, duplicate writing to the same block is prevented. That is, when a recorded block is designated again in the recording mode, the recording flag is read and recorded in the recorded flag register 10. The control circuit 10 checks the flag of the recorded flag register 10 and
When a recorded flag is detected, recording is prohibited. When deleting data recorded in a block, a deletion flag is written in the postfield. If only one piece of ID information is detected, writing of data to the corresponding block is prohibited, and a substitute process is performed. When performing the substitution processing, the control circuit 30 sets the substitution area a
Is set, and the light spot is moved to the alternative block. When the ID information of the replacement block is detected, predetermined data is written to the replacement block through the same operation as the above-described recording operation. When reading data stored in the optical disk medium 1 as described above, a reproduction mode is set, and ID information of a block to be reproduced is input. This input ID information is recorded in the recording / reproduction ID register 14. Meanwhile, the optical disk 1
The ID information reproduced from is stored in the ID shift register 11. Every time correct ID information is input, the shift register 11 sequentially transfers the ID information to the control circuit 30. When detecting one piece of ID information, the control circuit 30 executes the reproduction mode. That is, the reading position is determined based on the number of times of the detected ID information, and the data reading is started. In this case, only the data in the data part and the data error correction code are transferred to the data buffer 26, and the error correction code addition / error correction circuit 27
ECC check by. The reproduction signal is input to the demodulation circuit 8 via the reproduction signal amplification circuit 3 and the reproduction signal binarization circuit 4. When the ID comparator 16 outputs a coincidence signal between the reproduction ID information and the set target ID information, the recording / reproduction operation timing circuit 18 outputs a control signal to the recording / reproduction switching circuit 15 in response to the coincidence signal. The switching circuit 15 guides the demodulated signal of the demodulation circuit 8 to the data buffer 26. The reproduced data in the data buffer 26 is output to the host computer via the external interface 29 in many cases. [Effects of the Invention] As described above, in the MCAV optical disc device,
By providing three to five ID information areas in each block, the ID information in each block can be reliably detected, and data loss due to inability to reproduce can be avoided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a block format of an information recording medium used in an optical disk device according to an embodiment of the present invention, FIG. 2 is a plan view of an optical disk medium having an alternative area, and FIG. FIG. 3 is a block circuit diagram of the optical disk device according to the embodiment of the present invention. 1 optical disk medium, 2 optical head, 6 modulation circuit, 8 demodulation circuit, 10 recorded flag register,
11: ID shift register, 13: ID detection operation timing circuit, 14: Recording / reproduction ID register, 15: Recording / reproduction switching circuit, 16: ID comparator, 17: ID counter, 18 ... Recording / reproduction timing circuit, 26 ... Data buffer, 30 ... Control circuit.

Claims (1)

(57) [Claims] A step of preparing an information recording medium having a plurality of blocks each including a header area provided with a plurality of ID information in which block numbers are continuously stored and a data recording / reproducing area following the header area; and information from the data recording / reproducing area. When information is reproduced, a step of reproducing information on the condition that a predetermined number of pieces of ID information of the continuous ID information are retrieved from the header area, and information is recorded in the data recording / reproducing area At the time of information recording, the number of ID
Recording information on condition that the ID information is retrieved from the header area.