JPH09212937A - Magneto-optical disc apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the duplicated writing of data by accurately judging whether data are already recorded on a magnetooptical disc or not. SOLUTION: A magneto-optical disc device 1 detects a resynchronous pattern which is recorded into a RESYNC area of a data part 35 of a magneto-optical disc 3 to be inserted every several bytes of user's data before the recording of the user's data into a target sector and counts the number of detection patterns with an RESYN detection number circuit 11 to recognize that the sector already records the data when the results exceed a specified value N. The writing of the data is suspended. Thus, despite a defect of a medium in the magneto-optical disc, it is possible to accurately detect whether the data are already recorded into the magneto-optical disc thereby preventing the duplicated writing of the data.

Description

Detailed Description of the Invention

[0001]

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

[0002]

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

On the other hand, there is a recording apparatus for recording digital information by partially changing the physical structure of the 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 that can be viewed but does not need to be rewritten is rather suitable because it is not intentionally rewritten. 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. 3 shows the main internal structure of a sector on the 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, in these methods, a flag or S
If there is a medium defect in the WF area and the specific pattern cannot be detected from the flag, or if the specific data cannot be read from the SWF area, it is erroneously determined that the user data has not been written in the data section, and it is important for overwriting. There was a problem of erasing all data. Therefore, an object of the present invention is to accurately judge whether or not data has been recorded in a CCW compatible optical disk device and prevent overwriting of data.

[0010]

In order to solve such a problem, the present invention uses the reproduction signal obtained from the data portion of the sector before recording the user data in an arbitrary sector of the magneto-optical disk. Detecting means for detecting the resynchronization pattern recorded together with the user data, counting means for counting the number of detected resynchronization patterns, and when the count value of the counting means is a predetermined value or more, An overwrite preventing means for stopping data recording is provided. Therefore, at the time of recording user data, the number of patterns of the resynchronization pattern detected from the data part is counted, and if the count value is equal to or more than the predetermined value, the recording of the user data in the sector is stopped. It is possible to accurately detect whether or not the data has been recorded and prevent overwriting of the data. Further, a resynchronization pattern recording area is provided in the data portion, and the resynchronization pattern is recorded in the resynchronization pattern recording area as one pattern data for every several bytes of user data recorded in the data portion. As a result, even if there is a medium defect in the data portion of the sector, if the data has already been recorded in that sector, it can be accurately detected.

[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, the magneto-optical disk apparatus 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, a RESYNC detection circuit 10, and a RESYNC detection number measurement circuit 11. FIG. 2 is a diagram showing a configuration of the above-described magneto-optical disk 3. As shown in FIG. As shown in FIG. 2A, the magneto-optical disk 3 is provided with a plurality of tracks 31 spirally or concentrically, and each track 31 is plural as shown in FIG. 2B. Is divided into sectors 32.

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. In the data section 35, a SYNC signal indicating the start position of the data section, that is, a SYNC area 36 in which a sync pattern signal is recorded, a user data area 37, and several bytes of the recorded user data (B
, and a RESYNC area 38 in which a RESYNC signal used for synchronization at the time of data reproduction, that is, a resynchronization pattern signal is recorded, each area is in an unrecorded state in the initial state, Sometimes recorded respectively.

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, the reproduction signal of the magneto-optical disk 3 obtained from the head 4 is sent to the sector mark detection circuit 8 and the sector mark detection circuit 8 recognizes the head position of each sector. It Then, using this as a trigger, the ID read circuit 9 sets the ID area 34.
Is read. The target sector is accessed by repeating such an ID read operation. Head 4
Reaches the target sector, the RESYNC detection circuit 10 detects the resynchronization pattern in the RESYNC area 38 from the reproduction signal of the data portion 35 of the target sector.

As a method of detecting the resynchronization pattern signal of the RESYNC detecting circuit 10, there are the following methods.
That is, the first method is a method of always performing resynchronization pattern detection in the entire area of the data portion 35. Also,
The second method is to detect the resynchronization pattern only at the time when it is expected to be detected and its vicinity. That is, the sector mark area 33, the SYNC area 36, the RES
This is a method in which the timer is activated immediately before the detection of the YNC area 38 as a trigger and the detection operation is enabled only at each of the detection points.

When the RESYNC detection circuit 10 detects a resynchronization pattern signal in such a detection operation, it outputs it as a detection pattern signal A. The RESYNC detection number measuring circuit 11 inputs and counts the detection pattern signal A. That is, the resynchronization pattern is such that one pattern is recorded every several bytes of the user data when the user data is recorded, and the RESYNC detection number measurement circuit 11 inputs the detection pattern signal A and outputs the signal. Count A for each pattern. When the count value is equal to or more than the predetermined number N, the written signal B is output to the CPU 7. Upon receiving the write completed signal B, 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 written signal B is not output from the RESYNC detection number measuring circuit 11, the CPU
7 is a seek control circuit 5, a sector mark detection circuit 8 and I
The head 4 is again moved to the target sector by using the D read circuit 9, and the data recording circuit 6 is controlled to control the data section 3
The user data transferred from the host computer 2 is recorded in the user data area 37 of FIG. It should be noted that prior to the recording of this user data, the CPU 7 causes the SYNC area 36
The sync pattern is recorded in the RESYNC area 38.

Thus, this magneto-optical disk device 1
Before recording the user data in the target sector,
A resynchronization pattern recorded in the RESYNC area 38 of the data part 35 and inserted every few bytes of the user data is detected. If the number of patterns is equal to or more than the predetermined value N, it is recognized that the target sector is already recorded. However, the data write is suspended to prevent overwriting of data.

As a result, even if a medium defect occurs in the data section 35, the entire data section is not destroyed by this, and at most a few resynchronization patterns cannot be detected. , The predetermined value N is, for example, “data part 35
The total number of re-synchronization patterns in the area-5 "is set to an appropriate value to ensure whether the area of the data portion 35 is in the recorded state or the unrecorded state (the re-synchronization pattern is not recorded at all due to the erased state). Can be detected. Therefore, unlike the conventional overwriting prevention method, it is possible to reliably avoid a situation in which important data is erased by overwriting due to erroneous determination that the data area is unrecorded due to a medium defect.

Although the magneto-optical disk device 1 according to this embodiment has only the data write-once function, it is possible to write only once and read at any time by adding a data reproducing circuit to the 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.

[0022]

As described above, according to the present invention, at the time of recording user data, the number of resynchronization patterns detected from the data portion is counted, and when the count value is equal to or more than a predetermined value, the sector is recorded. Since the recording of the user data is stopped, whether or not the data has been recorded on the magneto-optical disk can be accurately detected, and the overwriting of the data can be prevented. Further, since the resynchronization pattern recording area is provided in the data part and the resynchronization pattern is recorded in the resynchronization pattern recording area as one pattern data for every several bytes of the user data recorded in the data part. Even if the magnetic disk has a medium defect, if data has already been recorded on the magneto-optical disk, it is possible to accurately detect the fact that the data has been recorded by appropriately selecting the above predetermined value.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a magneto-optical disk 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 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 ... RESYNC detection circuit, 11 ... RESYNC detection number measuring circuit, 31 ... Track, 32 ... Sector, 33 ... Sector mark area , 34 ...
ID area, 35 ... Data section, 36 ... SYNC area, 37
... user data area, 38 ... RESYNC area, A ... detection pattern signal, B ... written signal.

Claims (2)

[Claims] 1. A magneto-optical disk in which 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 unit of a plurality of divided sectors. And a data recording means for recording user data in the data part of the sector, wherein the user data is recorded from the reproduction signal obtained from the data part of the sector before recording the user data in the sector. With the detection means for detecting the resynchronization pattern recorded together with it, the counting means for counting the number of patterns of the detected resynchronization pattern, and when the count value of the counting means is a predetermined value or more, A magneto-optical disk device, comprising: an overwrite protection means for stopping data recording. 2. The resynchronization pattern recording area according to claim 1, wherein the resynchronization pattern recording area is provided in the data section, and the resynchronization pattern is one pattern for every several bytes of user data recorded in the data section. A magneto-optical disk device characterized by being recorded in a recording area.