JP2564418B2 - Optical disk writing / reading device - Google Patents

Description

The present invention relates to a writing / reading device for performing writing / reading processing and control in a rewritable optical disk device. For the purpose of providing a two-beam type optical disk writing / reading device which can be used as it is, a writing means for writing on an optical disk medium and data written by the writing means can be read immediately after writing. Having a read position at a proper position for reading from the optical disc medium, a read / write processing unit for processing write and read data, and a verify processing unit for checking data immediately after writing. In the write mode, the read / write processing means and the writing means, and the verify processing means and the reading means are connected, respectively.
In the read mode, it comprises switch means for connecting the read / write processing means and the read means, and control means for controlling the switch means, the read / write processing means and the verify processing means.

[Industrial applications]

The present invention relates to a writing / reading device for performing writing / reading processing and control in a rewritable optical disk device.

In recent years, a rewritable optical disk device has been put to practical use and used as an external storage device of a computer system. The optical disk device has an advantage that the storage capacity is much larger than that of the magnetic disk device, but on the other hand, it has a problem that the error rate is high. Therefore, in the optical disk device, in order to increase the reliability of the data to a desired level, more complicated and higher processing than that of the magnetic type is required.

[Conventional technology]

FIG. 7 is a diagram showing a schematic configuration of an example of a magneto-optical disc writing / reading apparatus. This magneto-optical method records data in the form of a change in the magnetization vector by irradiating a thin film magnetic material with a strong laser beam in the presence of a weak magnetic field, and at the time of reading, irradiates the laser beam and reflects it. In this method, data is recognized according to the deflection direction of light.

The write data is rearranged, added with a correction code, added with a synchronization byte, converted into a serial signal, and RLL (Run Length Limited) in the data processing unit 300.
The beam is subjected to modulation processing to a code, amplified in the beam control unit 250 to become a write pulse in synchronization with the write clock, and emitted from the head 240 as a ride beam to the track 12 on the optical disc 10. The beam control unit 250 also includes a read beam control circuit.When reading, the read beam is emitted from the head 240 onto the track 12, and the intensity of the reflected light that has passed through the deflection plate is converted into an electrical signal. The clock and data are restored in the control unit 250,
In the data processing unit 300, the read data is obtained through the reverse process including the error correction process.

As described above, in order to improve the reliability of the data, the data processing unit 300 uses an error correction code having a high error correction capability. Therefore, the correction code generation unit and the error correction unit in the data processing unit 300 are It has a very large and complicated structure.

In addition, as another means of improving the reliability, it is necessary to read the once written data again to check the reliability of the data. In order to realize this in the apparatus having the configuration shown in FIG. 7, even if the 1-bit data is written, it takes time for one rotation of the disk for the second check.

Therefore, in order to minimize this time, a configuration shown in FIG. 8 can be considered. As shown in FIG. 5, in addition to the write-only head 241, a read-only head 242 having a read position at a position several μm behind the write position is provided so that read can be performed immediately after writing. Then, as shown in FIG. 6, in the write mode, the write operation and the check operation are performed substantially simultaneously in parallel. This system is called a two-beam system because two beams are used for the writing beam and the reading beam. In this case, the beam control unit 250 in FIG. 7 is divided into a write beam control unit 251 and a read beam control unit 252, and the data processing unit 300 is divided into a write data processing unit 301 and a read data processing unit 302. The write data processing unit 301 carries out processing for write data, and the read data processing unit 302 carries out check of write data and processing of read data.

[Problems to be Solved by the Invention]

As described above, in an optical disk device, encoding with a code having a high error correction capability and error correction processing are indispensable, but the scale of the circuit for that purpose becomes enormous as the correction capability becomes higher, and the integration technology advances. Only then did it become realistic. Further, the encoding circuit necessary for processing the write data and the decoding circuit necessary for processing the read data have many common parts, and it is advantageous to share the writing process and the reading process. Therefore, the one-beam type data processing 300 of FIG. 7 is usually integrated in one LSI.

Therefore, also in the configuration of FIG. 8 using two beams, the ride data processing unit 301 and the read data processing unit 3
If 02 can be realized by using only the necessary functions with the same configuration as the one-beam type data processing unit 300, there is an advantage that the circuits and control methods stored in the one-beam type can be used as they are. .

However, in the 1-beam type data processing unit 300, while data input / output to / from the interface to the host computer is performed from one LSI via a bidirectional line as shown in the figure, two beams In the write data processing unit 301 and the read data processing unit 302, data is input and output from separate LSIs. Therefore, there is a problem that the LSI developed by the 1-beam method cannot be used as it is and must be separately developed.

Therefore, an object of the present invention is to provide a two-beam type optical disk writing / reading device in which the circuit and control method developed by the one-beam type can be used for each beam as they are.

[Means for solving the problem]

FIG. 1 is a block diagram showing the principle of the optical disk writing / reading apparatus of the present invention.

In the figure, an optical disk writing / reading device of the present invention comprises a writing means 20 for writing data on an optical disk medium 10 and a read position for reading the data written by the writing means 20 immediately after writing. Read means 22 for reading from the optical disc medium 10, read / write processing means 30 for processing write and read data, and verifier processing means 32 for checking data immediately after writing. In the write mode, the read / write processing means 30, the writing means 20, the verify processing means 32, and the reading means 22 are connected to each other, and in the read mode, the read / write processing means 30 and the reading means 22 are connected. Switch means 28 connecting the means 22,
The present invention is characterized by including the switch means 28, the read / write processing means 30, and the control means 40 for controlling the verify processing means 32.

[Work]

With such a configuration, the read / write processing means 30 has the same function as the data processing unit for 10 beams,
The circuit and control method for one beam can be used as they are. The verifying processing means 32 has only to exhibit the function of detecting an error in the read data among the circuit and control method for one beam, and the circuit and control method for one beam can be used as they are. It can be realized by using a part.

〔Example〕

 FIG. 2 is a diagram showing an embodiment of the present invention.

The data processing unit 305 has an error correction unit 306 that performs error detection and correction of read data, and an error correction coding unit 307 that performs error correction coding of data to be written. In the write mode, data processing unit 305 performs a predetermined process on the data to be written, validates write gate WTGT, and outputs it as write clock WTCC and write data WTDT. In the read mode, the read gate RDGT is enabled and data is read from the input read clock RDCC and read data RDDT and subjected to predetermined processing to be read data. SM is a signal indicating that a sector mark has been detected.

The data processing unit 325 has exactly the same configuration as the data processing unit 305. The data processing unit 325 performs a read operation in the write mode, reads the read clock RDCC and the read data RDDT data that are input with the read gate RDGT enabled, and detects an error of a level equal to or higher than a predetermined threshold value in the error detection process. If so, the process up to reporting to the MPU400 is performed. The data processing units 305 and 325 will be described later in more detail.

The host interface unit 410 mediates input / output of data between a host device (not shown) such as a computer system and the data processing unit 305. The MPU 400 performs processing such as data writing and reading according to a command from the host device received via the host interface unit 410.
Command 5,325.

The write beam controller 251 forms and amplifies a write timing pulse from the write clock WTCC and the write data WTDT and supplies it to the write head 241, and validates the signal SM when a sector mark is detected. It also has a function of reading the contents of the sector mark in order to inform the correct writing position. The read beam control unit 252 validates the signal SM when the sucker mark is detected, amplifies the signal from the read head 242, and outputs the read clock RDCC and read data.
Generate RDDT. The detailed configurations of the ride beam control unit 251 and the read beam control unit 252 will also be described later.

The multiplexers 280 to 283 switch the signal lines connecting the beam control units 251 and 252 and the data processing units 305 and 325 by the control signal from the MPU 400 to switch between the write mode and the read mode.

Next, the operation of the circuit shown in FIG. 2 in each of the write mode and the read mode will be described.

In the case of rewriting in the magneto-optical type optical disk device, it is necessary to previously erase the data at the portion to be written before the writing, but this processing is unnecessary or has already been completed. I shall. In the write mode, the multiplexer 280 selects and connects the signal WIDDT from the light beam control unit 251 as the RDDT of the data processing unit 305. The multiplexer 281 selects and connects the signal WIDCC from the ride beam controller 251 as the RDCC of the data processing receiver 305. The multiplexer 282 selects the signal SM from the light beam control unit 250 as the SM of the data processing unit 305 and connects it. The multiplexer 283 outputs the signal from the data processing unit 325.
The RDGT is selected and connected as the RDGT of the lead beam control unit 252.

Signals from data processing unit 305 WTDW, WTCC, WTGT and RDG
T is always connected to the corresponding individual of the ride beam controller 251. In addition, the signal RDDT from the read beam control unit 252,
The RDCC and SM are always connected to the corresponding parts of the data processing unit 325.

With the above connection, the data processing unit 305 and the write beam control unit 251 are connected, and the data processing unit 325 and the read beam control unit 252 are connected to each other, and the data processing unit 305, the ride beam control unit 251 and the write head 241 are connected. And the data processing unit 325, the read beam control unit 252, and the read head 242 perform a check immediately after writing.

In the read mode, the multiplexers 280 to 283 are exchanged in reverse. That is, multiplexers 280, 28
1 is the signal RDDT, RDC from the read beam controller 252 respectively
Select C and SM to select the RD of the data processing unit 305.
Connected to DT, RDCC, and SM, the multiplexer 283 selects the signal RDGT of the data processing unit 305 to select the read beam control unit 2
Connect to RDGT 52.

With the above connection, each signal of the data processing unit 305 and each signal of the read beam control unit 252 are connected, and the data processing unit 305, the read beam control unit 252, and the read head 242.
Read operation is performed. It should be noted that although a part of the connection between the data processing unit 305 and the light beam control unit 251 remains connected, the data processing unit 305 operates in the read mode, and therefore has no effect. Similarly, a part of the connection between the data processing unit 325 and the read beam control unit 252 remains, but since they are all input signals to the data processing unit 325, they have no effect.

FIG. 3 is a diagram showing a detailed configuration of the data processing unit 305 or 325 of FIG.

The format control unit 3000 is connected to the MPU 400 (FIG. 2) via the MPU interface and controls each unit according to a command from the MPU 400. The DMA control unit 3001 controls data input / output between the interface unit 410 (FIG. 2) and the data storage unit 3002. Data storage unit 3002
Temporarily stores write and read data for data rearrangement. The write data is stored in this data storage unit 3002.
The error correction code generation unit 3003 and the multiplexer 3007 perform error correction coding, the parallel-serial conversion unit 3005 converts the signals into serial signals, and the RLL modulation unit 006 RLL-modulates the write data W.
Output as TDT and write clock WTCC. The read data RDDT and the read data input as the read clock RDCC are demodulated in the RLL demodulation unit 3011, converted into parallel signals in the serial-parallel conversion unit 3010, and error detection and correction are performed in the error correction unit 3009 and the multiplexer 3008. Then, predetermined rearrangement can be performed in the data storage unit 3002, and the data is output via the DMA control unit 3001.

In the error correction redundant code generation unit 3003 and the error correction unit 3009, a code having a high error correction capability, for example, a Reed-Solomon code having a large minimum distance is used, and a huge circuit scale is obtained, but a considerable part of the syndrome operation is Shared in.

When used as the data processing unit 305, all of the configurations shown in FIG. 3 are used, but the data processing unit 325 is used.
In the write mode, the error detection function of the RLL demodulation unit 3011, serial-parallel conversion unit 3010, and error correction unit 3009 is used.

FIG. 4 is a diagram showing a detailed configuration of a part of each of the write beam control unit 251 and the read beam control unit 252.
The write beam control unit 251 generates a write pulse from the signals WTDT and WTCC, a write pulse generation unit 2510, an amplifier 2511 for amplifying the write pulse and sending it to the write head 241 (FIG. 2), from the write head 241. An amplifier 2513 that amplifies a signal at the index (sector mark) portion of the above and a VFO (Variabl Frequency Oscillator) 2512 that reproduces a clock WIDCC synchronized with the read data are provided. The read beam controller 252 includes an amplifier 2515 that amplifies a signal from the read head 242 (FIG. 2) and a VFO 2514 that reproduces a clock RDCC synchronized with the signal.

〔The invention's effect〕

As described above, according to the present invention, a circuit and a control system developed as a 1-beam type write / read device can be used as they are to realize a 2-beam type write / read device, and a new circuit is developed. -Evaluation can be saved.

[Brief description of drawings]

FIG. 1 is a diagram showing a principle configuration of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a diagram showing a detailed configuration of the data processing units 305 and 325 of FIG. 2, and FIG. 2 is a diagram showing a detailed configuration of part of the write beam control unit 251 and the read beam control unit 252 in FIG. 2, FIG. 5 is a diagram showing writing and reading positions in the two-beam system, and FIG. FIG. 7 is a diagram showing a writing operation in the optical disc system, FIG. 7 is a diagram showing a first example of a writing / reading device of a conventional optical disc device, and FIG. 8 is a second example of a writing / reading device of a conventional optical disc device. The figure to represent. In the figure, 10 ... Optical disk medium, 12 ... Track, 20 ... Write means, 22 ... Read means, 28 ... Switch means, 30 ... Read / write processing means, 32 ... Verify processing means , 40 …… Control means.

Claims (1)

(57) [Claims] 1. A writing means (20) for writing on an optical disk medium (10) and a reading position at a position where the data written by the writing means (20) can be read immediately after writing. Then, read means (22) for reading from the optical disk medium (10), read / write processing means (30) for processing write and read data, and verify for checking data immediately after writing In the write mode, the read / write processing means (30), the writing means (20), the verifying processing means (32) and the reading means (22) are connected and read out, respectively. In the mode, the read / write processing means (30) and the read means (22)
And a control means (40) for controlling the switch means (28), the read / write processing means (30) and the verification processing means (32). Optical disk writing / reading device.