JPS63282966A - System for detecting final recording sector - Google Patents

Abstract

PURPOSE:To prevent the reading of erroneous index information by detecting a preceding sector as a final recording sector when the error condition of reproducing data does not satisfy a prescribed reference. CONSTITUTION:For a recording data signal, an error correcting code, etc., are added in a correcting circuit 6, the signal is supplied through a modulating/ demodulating circuit 5 to a pick-up 3 and recorded to the prescribed area of the data area of a disk 1. After recording is completed, a recording signal is reproduced, supplied through the circuit 5 to the circuit 6, the processing of an error correction, etc., is executed, and when the number of the errors of a reproducing signal is a prescribed reference value or above, a control circuit a 8 re-records the same data at the shifting area in the area of the disk 1. Next, the circuit 8 records an index signal corresponding to the recording data at the next sector of the final recording sector of the index area. The circuit 6 detects the error condition of a reproducing index signal with a error correcting code, etc. In this case, the final recording sector of the index area is detected as the preceding sector.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a last recorded sector detection method particularly suitable for use in write-once type optical disk devices and the like.

[Summary of the invention]

In the present invention, the error status of reproduced data is detected using an error correction code or error detection code added to each sector, and the last recorded sector is detected in accordance with the detected status.

[Background technology]

FIG. 4 is a diagram conceptually showing areas on a conventional write-once optical disc. A disk is usually divided into two main areas: an index area and a data area. The user can record a desired data file in each sector (Dl to DS) of the data area. When a predetermined file is recorded, index information regarding the file is sequentially recorded in each sector (■□, I2) of the index area. Therefore, the latest index information of the data recorded on the disc can be obtained by reading the last recorded sector (I2 in the figure) of the index area.

Conventionally, in order to detect this final recording sector, the amplitude of the RF multiplied signal obtained while sequentially reproducing the index area is monitored. When the RF multiplied signal level falls below a predetermined reference value, the immediately preceding sector is detected as the final recording sector.

[Problem that the invention seeks to solve]

Since the conventional system detects the final recording sector based on the presence or absence of the RF multiplied signal, it is susceptible to the influence of noise in unrecorded sectors, and there is a risk of erroneously detecting the final recording sector. Furthermore, even if there is an error in the data of the last recorded sector, it is not known, so there is a risk of reading incorrect index information. As a result, new data may be overwritten on sectors that have already been recorded, destroying the original data.

Therefore, the present invention is intended to detect the last recorded sector more accurately and to prevent reading of incorrect index information.

[Means for solving problems]

In the last recorded sector detection method, the present invention reproduces a recording medium on which data is recorded by adding an error code such as an error correction code or an error detection code to each sector, and uses the error code to detect the error status of the reproduced data. When the error situation no longer satisfies a predetermined standard, the sector immediately before that error is detected as the final recording sector.

[Effect]

Data is recorded on a recording medium with an error code such as an error correction code or an error detection code added to each sector.

When the last recorded sector is detected, the recording medium is reproduced, and the error status of the reproduced data is detected using the error code. The error situation is compared with a predetermined criterion, and when the criterion is no longer satisfied, the immediately preceding sector is detected as the last recorded sector.

〔Example〕

FIG. 3 is a block diagram when the last recorded sector detection method of the present invention is applied to a write-once optical disc device. When a recording is commanded by the input means 9, a control circuit 8 comprising a microcomputer or the like controls a servo circuit 10 to rotate the disk 1 via the spindle motor 2. The pickup 3 is also moved to the index area via the servo circuit 10, and as described later, the final recording sector is detected and its data is read, and the address of the next data area to be recorded is calculated from the data. .

On the other hand, the recording data signal input from terminal 7 is sent to correction circuit 6.
The signal is subjected to processing such as interleaving and addition of an error correction code, and is then supplied to the modulation/demodulation circuit 5. The modulation/demodulation circuit 5 modulates the input signal by, for example, M2 and outputs the modulated signal. This output signal is amplified by the amplifier circuit 4 and supplied to the pickup 3. The pickup 3 controls laser light and the like to be irradiated onto the disk 1 in response to input signals. As a result, data is recorded in a predetermined sector of the data area of the disc 1.

The control circuit 8 causes the verify read to be executed immediately after the recording is completed. That is, the position of the pickup 3 is controlled via the servo circuit 10 to reproduce the signal just recorded.

The reproduced signal output from the pickup 3 is amplified by the amplifier circuit 4, and further subjected to M2 demodulation by the modulation/demodulation circuit 5. The demodulated signal is input to a correction circuit 6, where processing such as error correction and deinterleaving is performed. If errors in the reproduced signal cannot be corrected or the number of errors exceeds a predetermined reference value, the control circuit 8 causes the same data to be recorded again in a replacement area in the data area.

When predetermined data is recorded in the data area (including the replacement area) in this way, the control circuit 8
is controlled to move the pickup 3 to the sector next to the last recording sector in the index area, and the correction circuit 6 is controlled to generate and record an index signal corresponding to recording data.

As shown in FIG. 1, the index area of the disc 1 is divided into a plurality of areas (in this embodiment, there are two areas, A and B). For example, if we assume that index signals have already been recorded in sector ■4 of area A and sector ■I4 of area B corresponding to it (assuming that sector I4, ■' is the last recording sector), then sector I9,■
, +5, a new index signal is recorded. Note that the correspondence here is the first sector of areas A and B.
It means the position from.

When the index signal i is recorded in sector II5 of area A and sector II5 of area B, the control circuit 8 immediately causes the recorded data to be verified and read as in the case described above. The index signal 15 has an error code added thereto for each sector, such as an error correction code such as a Sudo-Solomon code, or an error detection code such as a CRC, as in the case of a data signal. The correction circuit 6 uses this error correction code and the like to detect error conditions in the reproduced index signal i5.

For example, if it is impossible to correct an error that has occurred in a sector, or the number of errors is large, and the specified verification read standards (which can be stricter than normal playback standards) are not satisfied, the next sector ■6 and ■16
The same index signal IS is recorded.

The index signals i recorded in sectors A and 6 are also immediately verified and read, and when both error conditions satisfy the criteria, the index signal recording operation is completed.

For example, if index signal 17 recorded in sector I7 of area A satisfies the verify read criteria, but the same index signal j7 recorded in sector J+7 of the corresponding area B does not satisfy the verify read criteria, then The same index signal 17 is recorded again in sectors I8 and j8 next to A and B, respectively. In this way, the recording operation of the same index signal is repeated until the verify read criteria are satisfied in the corresponding sectors of all areas A and B.

Note that area A and area B do not necessarily need to be centrally provided at different positions, for example,
It is also possible to set sectors with odd addresses as area A and sectors with even addresses as area B, such as +2, . . . .

Since the same index signal is recorded in a plurality of corresponding sectors in this way, if the index signal in one area deteriorates, it is possible to use the index signal in the other area.

When the same index signal is recorded in corresponding sectors of a plurality of areas, it is possible to detect the last recorded sector using the following method.

That is, when detecting the last recorded sector of the index area, the control circuit 8 controls the servo circuit 10 to cause the pickup 3 to sequentially reproduce each sector of one area (for example, area A) from the beginning, for example.

At this time, the control circuit 8 monitors the error status of each sector from the output of the correction circuit 6. Then, it is determined whether the error situation satisfies a predetermined criterion.

In sectors where no index signal is recorded, errors cannot be corrected (if an error correction code is used), or errors are detected (if an error detection code is used). Therefore, for example, if error correction is possible or no error is detected, it is possible to detect sectors in which no index signal is recorded.

The last recording sector is detected as the sector immediately before it.

Alternatively, if information regarding the length of the index area is recorded in a predetermined sector of the index area, that information is first read. The pickup 3 is then moved to the middle of the index area, and it is determined whether or not the neighboring sectors have been recorded. The recording state of a sector further 1/2 behind the distance between the position and the end when it has been recorded, and of a sector 1/2 ahead of the distance when it has not been recorded, is detected. Thereafter, similar operations are repeated until the final recording sector is detected.

In this way, the last recording sector can be detected in a shorter time than in the case described above.

However, even though the index signal is recorded, there are cases where the sector is erroneously detected as a sector that does not satisfy the criteria (unrecorded sector) due to noise or the like. Therefore, in order to avoid such a case, as shown in Figure 2, sectors that do not satisfy the criteria (indicated by (Example: 2) Replay area A until it is detected. When two sectors I N+1 and I N+2 that do not meet the criteria are detected in succession, the next two corresponding sectors ■IN in area B are detected.
, □, ■+, +2 are played. For example, in the case of a device that does not record data in sectors whose sector addresses cannot be read during recording, the value of n is determined by the number of sectors whose sector addresses cannot be read.
The probability of successive times is set to a value that is sufficiently small.

If two sectors I'NOx and I'N+2 are sectors that do not satisfy the criteria (in the case of B in the figure), the immediately preceding sector 2, I+2 is detected as the final recording sector. When the probability of detecting a recorded sector as an unrecorded sector is P, in reality sectors IN+□, ■IN, etc. are the last recorded sectors, but sectors I, , ■+
The probability of erroneously detecting , as the final recording sector is P2, which is considerably small.

If one of the corresponding sectors ■I, □, and I'1□ of area B satisfies the criteria (in the case of B2 or B3 in the figure), that sector (if the value of n is set to 3 or more, the most The rear sector (in the recording direction of the area, not in the rotational direction) is detected as the final recording sector.

As mentioned above, the final recorded sector is recorded so that it satisfies the standard conditions in all (two) areas A and B, so unless both sectors are erroneously detected as not satisfying the standard, the final recorded sector is Recording sectors are detected correctly.

Note that the present invention can also be applied to recording media that can be erased and rerecorded.

[Effects] As described above, the present invention has the following effects in the final recording sector detection method:
An error code such as an error correction code or an error detection code is added to each sector, and the recording medium on which data is recorded is played back, and the error status of the reproduced data is detected using the error code. When the standard is no longer satisfied, the immediately preceding sector is detected as the final recording sector, so the final recording sector can be detected accurately. When recording the same data in multiple sectors, 1
Even if the data in one sector deteriorates and an error occurs or the error cannot be corrected, it is possible to detect another sector as the final recording sector.

[Brief explanation of drawings]

1 and 2 are schematic explanatory diagrams of the index area of a disk when the last recorded sector detection method of the present invention is applied, FIG. 3 is a block diagram of the optical disk device, and FIG.
The figure is a schematic explanatory diagram of areas of a conventional disc. 1...Disk 2...Spindle motor 3...Pickup 4...Amplifier circuit 5...Modulation/demodulation circuit 6...Correction circuit 7...Terminal 8...Control circuit 9...Input Means 10: Servo circuit or more

Claims (1)

[Claims] A recording medium in which data is recorded with an error code such as an error correction code or an error detection code added to each sector is reproduced, and the error status of the reproduced data is detected using the error code. 1. A last recorded sector detection method, which detects the immediately preceding sector as the last recorded sector when the above criterion is no longer satisfied.