JPH1040646A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent overwriting of a data by detecting whether any data is recorded on an optical disk or not without adding a new circuit. SOLUTION: Before recording a user data in a sector of the optical disk 3, a synchronous pattern is detected from a regenerative signal obtained from a data part of this sector by a synchronization detecting circuit 10 which is used at the data reproducing time, and when the synchronous pattern is detected, data recording in this sector is stopped. As a result, without providing a new circuit, whether or not a data is already recorded in each sector is exactly detected, and hence overwriting of a data is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for recording user data on an optical disk.

[0002]

2. Description of the Related Art An optical disk apparatus for recording data on a recording medium such as an optical disk is a digital information recording apparatus that irradiates a laser beam while applying an external magnetic field to a recording medium to reverse its magnetization direction and record it as bit information. is there. Normally, when recording data on an optical disk, the data is erased by first aligning the magnetization of the recording area in a fixed direction, and then irradiating and flashing a laser beam to partially create a magnetization reversal area and record digital information. . Therefore,
New information can be recorded in an area in which data has already been recorded by erasing the area. As described above, the optical disc device is also called a rewritable optical disc device because it is characterized in that information can be written on the optical disc or its area can be rewritten.

On the other hand, there is a recording apparatus that records digital information by partially changing the physical structure of a recording medium. The change in the physical structure used in the actual recording apparatus generally involves, for example, changing the shape or utilizing a chemical change in the material. Since these are irreversible changes, it is not possible to newly erase an area in which information is already recorded and rewrite data. Such a once-writable magneto-optical disk storage device is generally called a write-once optical disk device. The write-once optical disc device is protected by hardware in order to prevent overwriting of data.

[0004] Some users do not need to rewrite data, and sometimes need a system that prevents accidentally erasing previously recorded data.
For example, in the case of an article record of a newspaper or the like, or a document material, a system which can be viewed but does not need to be rewritten, but rather a system which is not intentionally rewritten is often more useful. If a magneto-optical disk is used in such an application, the advantage of "rewritable" is a problem. Currently, generally used operating systems (OS) and the like prohibit overwriting by setting the attribute of a predetermined file in a recording medium to read-only (read only).

[0005] However, this is only managed by the OS on the computer in terms of software, and does not mean that the drive unit itself recognizes overwriting and performs protection. Therefore, there is a risk that data is erased due to a bug in the OS program or falsification of file attributes. For this reason, a write-once optical disc device has been effective for the above-mentioned applications. However, in recent years, a function that can be written only once in a magneto-optical disc device has been added, and CCW ( Conti
nious Co-posite Write On
ce) Compatible magneto-optical disk devices have been developed and used.

In this magneto-optical disk drive compatible with CCW,
As with the write-once optical disc device, overwriting of data is protected by hardware. The following two methods are used for this protection. First, the first protection method will be described. FIG. 4 shows a main internal configuration of a sector on a recording medium. In FIG.
The ID area 21 is an area where the address of the sector is recorded, and the data part 23 is an area where user data is recorded. The flag area 22 immediately before the data section 23 is a recording area for information indicating whether the sector has been written, and a specific pattern is written to the data section 23 after writing. Therefore, the CCW-compatible optical disk device reads the flag 22 immediately before recording user data, determines that a specific pattern has been written, determines that writing is impossible, and suspends the recording operation.

Next, in the second protection method, a SWF area 24 which is a writing area for information indicating whether or not data has been written is provided in a part of the data section 23, and the SWF area 24 has a hexadecimal value of, for example, "FF". Is recorded by recording specific data such as "." That is, when user data is written to the data section 23 in the SWF area 24, for example, a data pattern having a value “FF” is written. When recording user data in the data section 23, the CCW-compatible optical disc apparatus first reads a data area to be recorded, determines that "FF" is written in the SWF area 24 as a recorded area, Then, if it is determined that the area is already recorded, the recording operation is interrupted, and if it is determined that the area is a non-recorded area, the data section 23 is erased and the user data is recorded. I do.

[0008]

In such an optical disc apparatus compatible with CCW, a specific pattern is recorded in a flag immediately before a data portion of each sector (first method), or a SWF area of each data portion written is written. By recording the specific data in the second (second method), it is determined whether or not the data has already been written, thereby preventing the data from being overwritten.

However, the first method requires a flag recording circuit and a circuit for detecting a specific pattern from the flag. In the second method, a circuit for recognizing that "FF" is written in the SWF area is required. That is,
A conventional CCW-compatible optical disc device requires a new circuit for recording a pattern indicating that a sector has been recorded and a circuit for determining whether or not the data portion of the sector has been recorded. However, there is a problem that the circuit scale becomes large as compared with the above. Therefore, the present invention
An object of the present invention is to prevent overwriting of data on an optical disk without adding a new circuit in a CW-compatible optical disk device.

[0010]

In order to solve such a problem, according to the present invention, before recording user data in a sector, the data is recorded together with user data from a reproduction signal obtained from a data portion of the sector. A detection means for detecting a synchronization pattern and an overwrite prevention means for stopping data recording in a sector when a synchronization pattern is detected by the detection means are provided. Therefore, when a synchronization pattern is detected from the data portion of the corresponding sector, data is not recorded in the corresponding sector. A first detecting means for detecting a synchronization pattern recorded together with the user data from a reproduction signal obtained from a data portion of the sector before recording the user data in the sector; and recording the user data in the sector. A second detecting means for detecting a resynchronization pattern recorded together with user data from a reproduction signal obtained from a data portion of this sector before performing the first operation;
And overwriting prevention means for stopping data recording in the sector based on the detection output of either one of the second detection means and the second detection means. Therefore, if any one of the synchronization pattern and the resynchronization pattern is detected from the data portion of the corresponding sector, the data is not recorded in the corresponding sector. The second detection means detects a resynchronization pattern when the first detection means does not detect a synchronization pattern. The second detection means detects a specific N (N is an integer of 1 or more) resynchronization patterns in the data section.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a magneto-optical disk drive according to the present invention.
Is usually connected to the host computer 2. The host computer 2 uses the magneto-optical disk device 1 as an external storage device, and sends information to be recorded to the magneto-optical disk device 1, and receives information read by the magneto-optical disk device.

As shown in FIG. 1, a magneto-optical disk device 1 includes a magneto-optical disk 3, which is a recording medium, a head 4, a seek control circuit 5, a data recording circuit 6, a CPU 7, a sector mark detection circuit 8, and an ID read circuit. 9 and a SYNC detection circuit 10. FIG. 2 is a diagram showing a configuration of the above-described magneto-optical disk 3. As shown in FIG. As shown in FIG.
As shown in FIG. 2A, a plurality of tracks 31 are provided spirally or concentrically, and each track 31 is divided into a plurality of sectors 32 as shown in FIG. 2B.

The sector 32 comprises a sector mark area 33 indicating the head position of the sector, an ID area 34 in which the address of the sector is recorded, and a data section 35 in which user data is recorded. Also, the data section 35 includes S used to detect the head position of the data section.
YNC area 36, user data area 37, first RESYNC area 38 inserted every few bytes of user data to be recorded and used for data resynchronization, second RESYNC area 38
RESYNC area 39 and other RESYNC areas 4
0 is provided, and these areas are in an unrecorded state in an initial state, but are recorded at the time of data writing.

Next, the operation of the magneto-optical disk drive 1 configured as described above will be described. When the magneto-optical disk drive 1 receives a write command from the host computer 2, the CPU 7 transmits a seek command to the seek control circuit 5. By transmitting the seek command, the seek control circuit 5
Moves the head 4 to the track to which the target sector belongs.

When the head 4 moves to the target sector, a reproduction signal of the magneto-optical disk 3 obtained from the head 4 is sent to a sector mark detection circuit 8, and the information of the sector mark area 33 is detected by the sector mark detection circuit 8. The start position of each sector is recognized. The ID read circuit 9 reads the ID of the ID area 34 by using this as a trigger. The target sector is accessed by repeating such an ID read operation. When the head 4 reaches the target sector, the SYNC detection circuit 10 generates a SYNC from the reproduced signal of the data section 35 of the target sector.
The synchronization pattern in the area 36 is detected.

When the sync pattern is detected by the SYNC detection circuit 10, the sync pattern is output to the CPU 7 as a sync detection signal A. Upon receiving the synchronization detection signal A, the CPU 7 determines that the user data has already been written in the target sector, transmits an overwrite error message to the host computer 2, and interrupts the write command.

On the other hand, when the synchronization detection signal A is not output from the SYNC detection circuit 10, the CPU 7 moves the head 4 to the target sector again by using the seek control circuit 5, the sector mark detection circuit 8 and the ID read circuit 9. Then, the data recording circuit 6 is controlled to record the user data transferred from the host computer 2 in the user data area 37 of the data section 35. When recording this user data, the CPU 7 sets the SYNC area 36, the first RES
After recording each synchronization pattern in the YNC area 38, the second RESYNC area 39, and the other RESYNC areas 40, user data is recorded.

FIG. 3 is a block diagram showing another embodiment of the present invention. Here, in FIG. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. That is, in this embodiment, instead of the SYNC detection circuit 10 of FIG. 1, the SYNC detection circuit 11 and the RESYNC detection circuit 1
2 is provided. Next, the operation of the apparatus shown in FIG. 3 will be described. When the head 4 reaches the target sector by receiving the write command from the host computer 2, the SYNC detection circuit 11 detects the synchronization pattern in the SYNC area 36 from the reproduction signal of the data section 35 of the target sector.

When a sync pattern is detected by the SYNC detection circuit 11, a sync detection signal B is output to the CPU 7. If the synchronization pattern cannot be detected by the SYNC detection circuit 11, the RESYNC detection circuit 12 outputs the first RESYNC area 38 from the reproduction signal from the data section 35.
And the resynchronization pattern of each area of the second RESYNC area 39 is detected. Here, if a resynchronization pattern is detected from each area, a RESYNC detection signal (ie,
A resynchronization detection signal) C is output. CPU 7 is SYNC
Synchronization detection signal B or RESYNC from detection circuit 11
When receiving the resynchronization detection signal C from the detection circuit 12, it determines that the user data has already been written in the target sector, transmits an overwrite error message to the host computer 2, and interrupts the write command.

On the other hand, when the synchronization detection signal B is not output from the SYNC detection circuit 11 and the resynchronization detection signal C is not output from the RESYNC detection circuit 12,
Is a seek control circuit 5, a sector mark detection circuit 8, and an ID.
The head 4 is moved to the target sector again by using the read circuit 9, and the data recording circuit 6 is controlled to control the data section 35.
The user data transferred from the host computer 2 is recorded in the user data area 37 of (1).

In this embodiment, RESYNC is used.
The detection circuit 12 includes a first RESYNC area 38 and a second R
Although the data in each area of the ESYNC area 39 is detected, the present invention is not limited to this.
Can be realized by detecting N (1 ≦ N ≦ [integer in the total number of data in the first RESYNC area 38]) resynchronization data at a specific position.

As described above, the SYN used for data reproduction
Using a C detection circuit and a RESYNC detection circuit, it is determined whether or not the data portion of the sector has been written, thereby preventing overwriting of data. Therefore, there is no need to newly provide a circuit for determining whether or not the data portion of each sector has been written, and the device can be configured with a circuit size equivalent to that of an optical disk device that does not support CCW.

In the conventional overwriting prevention method, there is a medium defect in the flag or the SWF area, and a specific pattern cannot be detected from the flag (first method) or the SWF
When specific data cannot be read from the area (second method), it is erroneously determined that no user data has been written in the data portion, and there is a possibility that important data is erased by overwriting. However, even if a medium defect occurs in the data portion, the SYNC area 36, the first RESYNC area 38, and the second RESYNC area 39 do not become undetectable. Therefore, it is necessary to check each of the above areas as in the present invention. Can avoid the situation where important data is erased.

The magneto-optical disk drive 1 according to this embodiment has only a data write-once function. However, by adding a data reproducing circuit, a WORM ( Write Onc
e Read Many) It is needless to say that the device can be used as a device. The magneto-optical disk device 1 can be used as the above-described WORM device by switching the overwrite prevention function between valid and invalid according to an external switch, a switching signal from the host computer 2 and WORM / MO identification information of the recording medium. M that can be written at any time
It can also be used as an O (Magnet Optical Writer) device.

[0025]

As described above, according to the present invention, before recording user data in a sector, a synchronization pattern is used at the time of data reproduction from a reproduction signal obtained from a data portion of this sector. When a sync pattern is detected by a SYNC detection circuit (detection means), data is not recorded in the corresponding sector, so that the data portion of each sector has been written without providing a new circuit. Whether the data is overwritten can be accurately detected to prevent overwriting of data. Further, a synchronization pattern and a resynchronization pattern are detected from the data portion of the sector by a SYNC detection circuit (first detection means) and a RESYNC detection circuit (second detection means) used for data reproduction, respectively. When either the pattern or the resynchronization pattern is detected, data is not recorded in the corresponding sector. Therefore, it is also determined whether the data portion of the sector has been written without adding a new circuit. It can be detected accurately.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an optical disc device of the present invention.

FIG. 2 is a diagram showing a configuration of a magneto-optical disk in the apparatus.

FIG. 3 is a block diagram showing another embodiment of the optical disc device.

FIG. 4 is a diagram showing a configuration of a sector of a conventional magneto-optical disk.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magneto-optical disk device, 2 ... Host computer, 3
... Magneto-optical disk, 4 ... Head, 5 ... Seek control circuit,
6 data recording circuit, 7 CPU, 8 sector mark detection circuit, 9 ID read circuit, 10, 11 SYNC detection circuit, 12 RESYNC detection circuit, 31 track, 32 sector, 33 sector mark area , 34 ... I
D area, 35 data section, 36 SYNC area, 37 area
User data area, 38... First RESYNC area, 39
... Second RESYNC area, A, B ... Synchronization detection signal, C ...
Resynchronization detection signal.

Claims (4)

[Claims] A plurality of tracks are formed concentrically or spirally on a surface, each track is divided into a plurality of sectors, and data is written in a plurality of divided sectors. Data recording means for recording user data in a data portion of the sector; and a synchronization pattern recorded together with the user data from a reproduction signal obtained from the data portion of the sector before recording the user data in the sector. An optical disc device comprising: a detecting unit for detecting; and an overwrite preventing unit for stopping data recording in the sector when a synchronous pattern is detected by the detecting unit. 2. A plurality of tracks are formed concentrically or spirally on a surface, each track is divided into a plurality of sectors, and data is written in units of the plurality of divided sectors. Data recording means for recording user data in a data portion of the sector; and a synchronization pattern recorded together with the user data from a reproduction signal obtained from the data portion of the sector before recording the user data in the sector. A first detecting means for detecting, and a second re-synchronization pattern which is recorded together with the user data from a reproduction signal obtained from a data portion of the sector before recording the user data in the sector. Detecting means; and overwriting for stopping data recording in the sector based on a detection output of one of the first and second detecting means. An optical disk device comprising: a prevention unit. 3. The optical disk device according to claim 2, wherein the second detection means detects a resynchronization pattern when the first detection means does not detect a synchronization pattern. 4. The method according to claim 2, wherein the second detecting means detects a specific N (N is an integer of 1 or more) resynchronization patterns of the data portion. Optical disk device.