JP2003006981A - Information recording / reproducing device - Google Patents

Abstract

(57) [Problem] To easily detect falsification of a recording medium by utilizing a device originally provided without a special additional circuit or device, and to make it possible for a user to use data by duplicating data. An object of the present invention is to provide an information recording / reproducing apparatus capable of performing recording for detecting originality without reducing a data area. An information recording / reproducing apparatus provided with an error detecting mechanism, wherein an error generating means (CD-ROM encoder 15, CPU 17) capable of intentionally generating an error at an arbitrary position, and Error determining means (C
PU17, RAM19), and detects the originality or falsification of the recording medium by intentionally detecting an error generated and recorded at one or more locations.
There are 5 other items

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus, and more particularly to an optical disc (CD-*. DVD-
*), Magneto-optical disk (MO), magnetic disk (HD / FD /
Tapes), memory cards (RAM, ROM, optical memory, magnetic memory) and the like, which mainly relate to devices that use a recording medium including error correction in a system using a computer.

[0002]

2. Description of the Related Art Conventionally, the invention of tampering and detection of originality is often found in magnetic cards and optical cards as substitutes for currency. For example, in the technique disclosed in Japanese Patent Laid-Open No. 10-233057, falsification is detected by duplicating and recording. Further, when duplexing, one of them performs reverse recording to improve reliability for error correction.

[0003]

However, with the development of PCs and their peripheral devices, not only card systems that can be used only in specific devices but also PC card memories and CD-R / RW / DVDs have been developed. For example, the demand for falsification and originality detection has increased. In response to this request, Japanese Unexamined Patent Application Publication No. 2001-084704 takes a method of making a sector in which an error occurs artificially in the medium manufacturing process and stamping it on the optical disc on the medium side in order to make copying difficult. Has been. This method may be effective on a read-only medium, but it is difficult on a recording site, a write-once or recordable medium.

The present invention has been made in view of these problems, and makes it possible to easily detect tampering of a recording medium by utilizing a device provided from the beginning without a special additional circuit or device. An object of the present invention is to provide an information recording / reproducing apparatus capable of performing recording for detecting the originality without reducing the data area available to the user due to duplication of data or the like.

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 is an information recording / reproducing apparatus having an error detecting mechanism, wherein an error is intentionally generated at an arbitrary position. The original of the recording medium is provided with an error generating means capable of performing the error detection, an error determining means for determining whether the detected error is caused by the error generating means, and detecting an error intentionally generated and recorded at one or more places. The most important feature is an information recording / reproducing device that detects sex and falsification.

According to a second aspect of the present invention, there is provided the information recording / reproducing apparatus according to the first aspect, wherein the information recording / reproducing apparatus automatically selects a location where an error occurs, and a location where the error occurs. The main feature of the information recording / reproducing apparatus is that the recording / reproducing apparatus includes a communication means for notifying the host side.

The invention according to claim 3 is the invention according to claim 1 or 2.
The described information recording / reproducing apparatus is characterized mainly in the information recording / reproducing apparatus, which is a position on the recording medium that is not allocated to a location traceable from the file system, where an intentionally generated error is recorded.

The invention according to claim 4 is the invention according to claim 1 or 2.
In the information recording / reproducing apparatus described above, the point at which an error that is intentionally recorded is a position on the recording medium that is assigned to specific user data that has little effect even if some error occurs. The main feature is a recording / reproducing device.

According to a fifth aspect of the invention, there is provided the information recording / reproducing apparatus according to any one of the first to fourth aspects, in which the points where intentionally generated errors are recorded are dispersed on the recording medium. The main feature is the information recording / reproducing device which is the position.

According to a sixth aspect of the invention, there is provided the information recording / reproducing apparatus according to any one of the first to fifth aspects, in which an error that is intentionally generated follows a certain rule, and a certain rule is applied during reproduction. An information recording / reproducing apparatus capable of reversibly canceling an error and avoiding a data error is a main feature.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings and tables. FIG. 1 is a block diagram showing the configuration of an optical disk device (recordable CD drive) according to an embodiment of the present invention.

This optical disk device includes an optical disk 1, a spindle motor 2, a motor driver 3, a servo 4, an optical pickup 5, a read amplifier 6, a CD decoder 7, and a CD.
-ROM decoder 8, buffer manager 9, buffer RAM 10, ATAPI / SCSI interface 1
1, D / A converter 12, ATIP decoder 13, C
It comprises a D encoder 14, a CD-ROM encoder 15, a laser control circuit 16, a CPU 17, a ROM 18, and a RAM 19 (including a non-volatile RAM). CPU1
Reference numeral 7 controls the whole using the RAM 19 according to the procedure and data on the ROM 18.

In this optical disk device, an optical disk 1 is rotated by a spindle motor 2. The spindle motor 2 is controlled by the motor driver 3 and the servo 4 so that the linear velocity becomes constant. The linear velocity can be changed stepwise. The optical pickup 5 includes a semiconductor laser (not shown), an optical system, a focus actuator,
It incorporates a track actuator, a light receiving element, and a position sensor, and irradiates the recording surface of the optical disc 1 with the laser light L.

Parity and checksum are used for the error detection mechanism. Here, description will be made using typical parity.

[0015]

[Table 1]

At the time of recording, for example, in even parity, the data bits (bit0 to bit3 in this case) are viewed, and the parity bit is set to 1 so that the total of 1 becomes an even number.

[Table 2]

Then, assume that the data is read as described above during reproduction. The sum of 1s is odd even though the parity is standing. In other words, it can be seen that this data contains untrustworthy errors. However, in this state, it is not known which data caused the change. Many systems give this a read error and give up playback.

[0018]

[Table 3]

By extending the concept of parity and calculating and adding the parity in the time series direction when there are a plurality of data, the location of the changed data can be known. Using this, if the changed bit is inverted, the original correct data is restored. In the above example, 9 bits are consumed for 16-bit actual data, but there is a trade-off between detection capability and capacity, and in reality, each information recording / reproducing method is in a state suitable for the situation. ing. Although the error detection and error correction are performed by the above mechanism, the parity and the checksum are actually provided for each minimum unit of recording (called a sector. Each sector has a unique address number to distinguish it from the user). It is calculated and recorded including such error detection data. In this way, error detection and error correction are often performed for each sector, but the same may be performed for blocks in which some sectors are grouped together to further improve reliability. In addition, data may be calculated separately for detection and correction, or double error detection / correction may be performed.

Data to be recorded is stored in the buffer RAM 10 shown in FIG. 1. Normally, the CD-ROM encoder 15 adds data for error detection as described above. Here, by instructing the CD-ROM encoder 15 from the CPU 17, it becomes possible to record the data that causes an intended error in any place (the CD-ROM encoder 15 and the CPU 17 are error generating means). Then, by storing the location in the RAM 19, it becomes possible to determine whether the error is caused by the error generating means (the CPU 17 and the RAM 19 are error determining means). In addition, ATAPI / SCSI interface 11
By communicating with the host through the host, it is possible to provide the host with the location of the error, or conversely, receive the location of the error from the host and make an error at an arbitrary position.

In view of the above embodiment, the method of originality / tampering detection using error detection in recording and reproduction is shown as a flowchart. FIG. 2 shows a flowchart for recording. First, a sector (address) in which error detection is to be generated is determined (101). The process moves to the recording process, and when it comes to the sector where each error detection is generated (102), the data for error detection is processed and changed (103) and then recorded (104). Normal recording is done as it is. This is repeated until the end, and recording is completed. (However, if verification processing etc. is performed after recording is completed, an error will occur as it is, so processing such as skipping the address that caused the error detection is required. Here, it is also possible to generate the address prepared in (101) in the device by a numerical value or random number unique to the device and communicate with the host.

Next, a flow chart at the time of reproduction will be shown based on FIG. Sector (201) prepared in (101)
Check one by one (202). If an error is detected in each sector (203, 204), it is determined to be the original (205). On the contrary, if no error is detected in any one of the sectors, it is determined to be duplicate (2
06). The number of sectors used for detection and the threshold used for determination of duplicates / originals depend on the actual system.

In order to make the above contents easy to understand, description will be given as a one-dimensional diagram. According to FIG. 4, the squares arranged side by side are one sector. A logical address is assigned to each sector, which is a value that can be uniquely determined. The recording / reproducing head moves left and right to read data at a predetermined address. The sector contains data and its error detection data and error correction data, and can be recorded and reproduced at one time. When the read / write head comes to the sector at address 11, error detection works, and the sector cannot be read due to an error, so it is not copied. The same applies to the sector of address 17. As a result, the copy made on the recording side is different from the original.

Next, FIG. 5 shows a case where the error detection sectors are dispersed and recorded at different positions. Address 4
It is only necessary to be able to detect an error that does not depend on dust, scratches, or deterioration, as in item No. 14 and No. 14, but this is not always the case. In some cases, such as at addresses 2, 9 and 21, dust adheres and a reproduction error occurs before and after the dust. In order to suppress the influence of error detection such as noise as much as possible,
It is important to arrange the error detection sectors so that the physical positions are dispersed. Localizing the error detection sector makes it more susceptible to dust, scratches, and deterioration.

FIG. 6 shows a case where the error detection sector is arranged while avoiding the sector used by the file system. In such a one-dimensional address space file system, the metadata that defines a file (data that performs volume management, directory / file management, etc., often cannot be seen by the user) and the data of the file itself are in the same address space. Mixed. It is good if the size of the file is predetermined and is not updated after that, but if not, each file is updated asynchronously and fragmentation occurs, leaving gap-like sectors that are never used. By utilizing this, the error detection sector can be used for error detection without affecting the file or file system metadata. There is no need to wait for a gap, and you may decide in advance an address that cannot be used in the file system.

Further, FIG. 7 shows a state in which an error detection sector is embedded in a moving image or audio data which has the least influence on a file. Basically, it is similar to FIG. 6, except that when recording a valid file, attention is paid to the contents of the file, and the error detection sector is embedded only in the case of a moving image or sound. You may rely on the operating system to distinguish between video and audio data,
It is easy to distinguish from a file that occupies a large size on the recording medium. Even if an error occurs in the reproduction data, it becomes noise that causes almost no problem to human ears and eyes.

Although the above description concerns the arrangement of the error-detected sectors, FIG. 8 shows a method of recovering the sector in which the error is detected. When an error is detected, the error detection data should be returned to the original error detection data according to a certain rule (YnΣn = f (Xn)). There are various rules to be used, but constant addition / subtraction X = X + N bit inversion (10101101 → 01010010) bit shift (11001111 → 00111111) and the like can be considered. If it is a relatively simple rule, it can be easily incorporated into hardware and restoration processing can be performed at high speed. Then, if recalculation is performed, correct error detection can be performed. In FIG. 3, after the error detection (203),
It can be used as original data by performing restoration processing.
If you still get an error, you can predict that it is a spontaneous error due to dust, scratches, deterioration, etc.

If an error correction mechanism is further used in the system described above, an error at the time of reproduction can be automatically avoided. However, the error recorded in advance is
It is necessary to limit the error to the range that can be corrected by the error correction mechanism. Because of these mechanisms, error-free clean replication succeeds, but differs from the original.

[0029]

According to the first aspect of the present invention, the originality / falsification can be detected by using an error detection mechanism, which is often used in recent information recording / reproducing methods and media, as a reverse hand. Unlike conventional dedicated systems and closed standards that were expensive in the past, this does not require a special dedicated circuit, and it is possible to construct a system that can detect originality and tampering with existing general-purpose components at low cost. is there.

According to the second aspect of the present invention, since the error position is automatically generated by the device, the device can be used easily without any prior instruction. Since the determination of the error position can be delayed until the time of recording, confidentiality can be enhanced.

According to the third aspect, the error position is a position irrelevant to the file system. This allows
Detection can be performed without jeopardizing the data and file system actually used, and it can be a more robust system.

According to the fourth aspect, although the data is actually valid, the error position is a place where the data tends to be large data such as an image / sound file and a slight data error has little influence in actual use. ing. As a result, it is possible to perform detection that is unlikely to be affected by an error. If the file system metadata (volume management, directory / file management, etc.) that is not such data is disturbed, it is highly possible that the file cannot be reached.
Such a situation can be avoided. In addition, so-called watermark (digital watermark) effect can be expected as long as the data is not a program but a content such as an image / sound file.

According to the fifth aspect, by dispersing the error positions, it is possible to reduce the influence of a burst error such as scratches, stains or deterioration occurring at a specific portion of the medium.

According to the sixth aspect of the present invention, the error detection data can be restored as the correct error detection data and can be used correctly by performing the specific work. This has the effect of enabling correct error detection and preventing the original functions from being impaired. Further, there is an effect that it is not necessary to sacrifice the recording capacity or a part of the data for the error detection.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an optical disc device (recordable CD drive) according to an embodiment of the present invention.

FIG. 2 is a flowchart at the time of recording in originality detection and tampering detection processing.

FIG. 3 is a flowchart at the time of reproduction in originality detection and tampering detection processing.

FIG. 4 is an explanatory diagram of originality detection / falsification detection processing.

FIG. 5 is an explanatory diagram of originality detection / falsification detection processing.

FIG. 6 is an explanatory diagram of originality detection / falsification detection processing.

FIG. 7 is an explanatory diagram of originality detection / falsification detection processing.

FIG. 8 is an explanatory diagram of originality detection / falsification detection processing.

[Explanation of symbols]

1 optical disc 11 ATAPI / SCSI interface 15 CD-ROM encoder 17 CPU 19 RAM

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G11B 20/18 570 G11B 20/18 570N

Claims (6)

[Claims] 1. An information recording / reproducing apparatus having an error detecting mechanism, wherein an error generating means capable of intentionally generating an error at an arbitrary position, and whether the detected error is due to the error generating means. An information recording / reproducing apparatus characterized by comprising an error determining means for determining whether the recording medium is original or original and tampering detected by detecting an error generated and recorded at one or more locations. 2. The information recording / reproducing apparatus according to claim 1, wherein
An information recording / reproducing apparatus comprising: a selection means for the information recording / reproducing apparatus to automatically select a location where an error occurs, and a communication means for the information recording / reproducing apparatus to inform a host side of a location where an error occurs. 3. The information recording / reproducing apparatus according to claim 1 or 2, wherein a portion where an error that is intentionally recorded is recorded is a position on a recording medium that is not assigned to a location traceable from a file system. An information recording / reproducing apparatus characterized by: 4. The information recording / reproducing apparatus according to claim 1 or 2, wherein a portion where an error that is intentionally recorded is recorded is assigned to specific user data that has little influence even if some error occurs. The information recording / reproducing apparatus is characterized in that it is a position on the recording medium. 5. The information recording / reproducing apparatus according to any one of claims 1 to 4, wherein the locations where intentionally generated errors are recorded are dispersed positions on the recording medium. Information recording / reproducing apparatus. 6. The information recording / reproducing apparatus according to any one of claims 1 to 5, wherein an error that is intentionally generated follows a certain rule, and reversibly based on the certain rule during reproduction. An information recording / reproducing apparatus characterized in that an error can be canceled and a data error can be avoided.