Abstract:
A magnetic disc device is disclosed, having a disc enclosure for enclosing a magnetic disc medium on which data has been recorded, a circuit for processing a signal that has been read from the magnetic disc device, wherein a signal that is read from the magnetic disc is output from only an interface.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a magnetic disc apparatus, and in particular, to improvements of a hardware structure and a circuit structure of a magnetic disc apparatus that accomplishes a copy protect function.  
           [0003]    2. Description of the Prior Art  
           [0004]    Conventional magnetic discs do not have a copy protect function. The copy protect function is conventionally accomplished as a write protect function using a switch or a jumper disposed on a circuit board. The purpose of the write protect function is to prevent user data from being mistakenly destroyed with data that is written when it is restored from a magnetic disc that is defective. On the other hand, digital high quality data tends to be stored to a magnetic disc.  
           [0005]    Digital high quality video data such as movies and video clips can be copied without a deterioration of the picture quality. Thus, from a view point of the copyright protection of digital contents, needs for copy-protecting digital high quality pictures are becoming strong To satisfy such needs, for example JPA 11-306648 (referred to as related art reference 1) discloses an information record medium having a copy protect function. According to the technology disclosed in the related art reference 1, an information record area for recording predetermined information and a trap area for causing a copying device to malfunction are formed so as to prevent all information including encrypted information recoded on an optical disc from being copied as it is.  
           [0006]    In addition, JPA 61-206905 (referred to as related art reference No. 2) discloses a magnetic disc having a copy protect code. The magnetic disc of the related art reference 2 comprises (1) a magnetic disc device of which a magnetic disc is used as a record medium, (2) a magnetic disc device controlling circuit for generating a random number and recording the generated random number to the magnetic disc, and (3) a host system of which a magnetic disc device is used as a recording device. The magnetic disc has (1-1) an area for recording information received from a host system (this area is referred to as information area) and (1-2) an area for recording random number generated by the magnetic disc device controlling circuit (this area is referred to as random number area). When the host system records information to the information area of the magnetic disc, the magnetic disc device controlling circuit records a random number to the random number area while the host system records information to the information area of the magnetic disc. After they have been recorded, the random number that has been recorded in the random number area is read. The random number is recorded to a particular information area (second information area) different from the information area. When the information area is read from the magnetic disc, the random area is also read The relation between the random number recorded in the second information area and the random number that is read therefrom is verified.  
           [0007]    However, in the technology of the related art reference 1, the trap area is formed at a particular position in such a manner that when an RF copy (disc copy) is attempted, the trap area prevents the disc copy from being performed. Thus, the technology of the related art reference 1 is limited to an optical disc of which data is spirally written. Consequently, the related art reference 1 cannot be applied to a magnetic disc of which tracks are recorded on concentric circles (namely, a hard disc drive).  
           [0008]    In addition, according to the technology of the related art reference 1, although a copy operation using disc copy command can be prohibited, when data is read using read command and then the read data is written to a destination record medium, the data can be easily copied.  
           [0009]    The technology of the related art referenced 2 is applied to a magnetic disc using servo-surface servo-system as a head aligning system for a magnetic disc. Thus, the technology of the related art reference 2 cannot be applied to a magnetic disc using the data-surface servo-system that has been widely used.  
           [0010]    In addition, according to the technology of the related art reference 2, a check program for checking a protect code is recorded in a data area along with data. In this method, when data is read from a source magnetic disc sector by sector, rather than a file system level managed by the OS, and then the read data is written to a destination record medium, the data can be easily copied.  
         SUMMARY OF THE INVENTION  
         [0011]    An object of the present invention is to provide a magnetic disc having a hardware structure and a circuit structure that accomplish a copy protect function.  
           [0012]    According to a first aspect of the present invention, there is provided a magnetic disc device having a disc enclosure for enclosing: a magnetic disc medium on which data has been recorded; a circuit for processing a signal that has been read from the magnetic disc device, wherein a signal that is read from the magnetic disc is output from only an interface.  
           [0013]    The magnetic disc device according to the first aspect may further comprise: a record medium on which a first authentication code has been recorded; an interface for inputting a second authentication code; collating means for collating the first authentication code with the second authentication code; and means for reading the data and outputting the read data to the outside only when the first authentication code matches the second authentication code.  
           [0014]    The magnetic disc device according to the first aspect may further comprise: means for decreasing the number of times of a retry operation performed when a data read error takes whenever data is read from the magnetic disc medium.  
           [0015]    The magnetic disc device according to the first aspect may further comprise: means for limiting the number of times that data is read from the magnetic disc medium.  
           [0016]    According to a second aspect of the present invention, there is provided a magnetic disc medium on which data has been recorded, comprising: a record medium on which a first authentication code has been recorded; an interface for inputting a second authentication code; collating means for collating the first authentication code with the second authentication code; means for reading the data and outputting the read data to the outside only when the first authentication code matches the second authentication code.  
           [0017]    According to a third aspect of the present invention, there is provided a magnetic disc device, comprising: a magnetic disc medium on which data has been recorded; and means for decreasing the number of times of a retry operation performed when a data read error takes place whenever the data is read from the magnetic disc medium.  
           [0018]    According to a fourth aspect of the present invention, there is provided a magnetic disc device, comprising: a magnetic disc medium on which data has been recorded; and means for limiting the number of times that data is read from the magnetic disc medium.  
           [0019]    These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of the best mode embodiment thereof, as illustrated in the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0020]    [0020]FIG. 1 is a schematic diagram showing the concept of a magnetic disc according to an embodiment of the present invention;  
         [0021]    [0021]FIG. 2 is a flow chart showing a collating operation of authentication code according to the embodiment of the present invention;  
         [0022]    [0022]FIG. 3 is a flow chart showing an operation for decrementing the number of times of a retry operation as the number of times of a reproducing operation increases according to the embodiment of the present invention; and  
         [0023]    [0023]FIG. 4 is a schematic diagram showing the structure of a magnetic disc device according to another embodiment of the present invention. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0024]    Next, with reference to the accompanying drawings, embodiments of the present invention will be described in detail.  
         [0025]    A magnetic disc device according to the present invention is inserted into a reproducing device such as a docking station connected to a television set. Digital video data as contents such as movies have been recorded on the magnetic disc device. The magnetic disc device and the reproducing device are electrically connected with an interface corresponding to the IEEE 1394 standard. The digital video data is transferred from the magnetic disc device to the reproducing device through the interface. After the digital video data is decoded by the reproducing device, the decoded video data is transferred to the television set  
         [0026]    A business use dedicated recording device disposed in for example a rental shop records digital video data as contents to the magnetic disc. After the video data is recorded to the magnetic disc, it is rented to a user. The user reproduces the contents with the reproducing device and watches them with the television set.  
         [0027]    The magnetic disc according to the present invention prevents contents recorded thereon from being illegally copied.  
         [0028]    [0028]FIG. 1 shows the structure of a magnetic disc  1  according to an embodiment of the present invention. The magnetic disc  1  comprises a disc enclosure  2 , a magnetic disc medium  11 , an actuator portion  14 , a spindle motor  15 , a spindle motor driver  16 , a VCM driver  17 , a read/write channel circuit  18 , a disc controller  19 , a microcomputer  20 , a ROM  21 , and a serial interface  22 . The disc enclosure  2  encloses those structural devices. The actuator portion  14  has a read/write head  12  and a read/write amplifier circuit  13 . In addition, an interface connector  23  is disposed outside the disc enclosure  2 .  
         [0029]    The read/write head  12  records data that is input from the read/write amplifier circuit  13  to a data area  14 B or a system area  14 A of the magnetic disc medium  11 . The read/write head  12  outputs data that is read from the magnetic disc medium  11  to the read/write amplifier circuit  13 . The read/write amplifier circuit  13  equalizes and amplifies the data that is input from the read/write channel circuit  18  and output the amplified data to the read/write head  12 . In addition, the read/write amplifier circuit  13  equalizes and amplifies the data that is read by the read/write head  12 . The read/write channel circuit  18  modulates data that is input from the disc controller  19  and outputs the modulated data to the read/write amplifier circuit  13 . In addition, the read/write channel circuit  18  demodulates data that is input from the read/write amplifier circuit  13  and outputs the demodulated data to the disc controller  19 . The disc controller  19  controls the interface corresponding to ATA (AT Attachment) or SCSI (Small Computer System Interface). In addition, the disc controller  19  manages sectors of the magnetic disc medium  11 . The serial interface  22  controls an interface such as IEEE 1394 or USB (Universal Serial Bus). The ROM  21  stores a program as a memory with which the microcomputer  20  collates authentication code (that will be described later).  
         [0030]    The disc enclosure  2  is not affected by dust, gas, and so forth unless it is opened.  
         [0031]    When the interface for use corresponds to THE IEEE 1394 standard, encrypted digital video data is supplied to the serial interface  22  through the interface connector  23  The serial interface  22  decrypts the digital video data. The decrypted digital video data is input to the disc controller  19 . The decrypted digital video data is supplied to the read/write head  12  through the read/write channel circuit  18  and the read/write amplifier circuit  13 . The read/write head  12  recodes the decrypted digital video data to the data area  14 B of the magnetic disc medium  11 .  
         [0032]    When a read command is input from a host controller  101  through the interface connector  23 , the video data is read from the data area  14 B of the read/write head  12  in the disc enclosure  2  by the read/write head  12 . The video data is supplied to the serial interface  22  through the read/write amplifier circuit  13 , the read/write channel circuit  18 , and the disc controller  19 . The serial interface  22  encrypts the video data. The encrypted video data is output from the interface connector  23 .  
         [0033]    [0033]FIG. 2 shows an operation of the microcomputer  20  controlled by an authentication program stored in the ROM  21 .  
         [0034]    Authentication code is pre-written to a storage area that can be accessed by the microcomputer  20  and that cannot be used by the user. The authentication code is pre-written to for example the system area  14 A of the magnetic disc medium  11  or a non-volatile memory (not shown).  
         [0035]    When the microcomputer  20  is controlled by the authentication program, the microcomputer  20  authenticates with the host controller  101 . Only when they have been successfully authenticated between them, the microcomputer  20  can read and write digital video data as contents.  
         [0036]    Next, with reference to FIG. 2, the operation of the embodiment will be described. In this example, it is assumed that an external bus  100  corresponds to the IEEE 1394 standard.  
         [0037]    When the power of the magnetic disc  1  is turned on, the authentication code is read from the system area  14 A (at step  301 ). Thereafter, the encrypted authentication code is input from the host controller  101  through the external bus  100 . The serial interface circuit  22  decrypts the encrypted authentication code and outputs the decrypted authentication code to the disc controller  19  (at step  302 ). The microcomputer  20  collates the authentication code that is read from the system area  14 A with the decrypted authentication code (at step  303 ). When they match at step  303 , a read command or a write command is accepted (at step  304 ). When they do not match, a read command and a write command are not accepted.  
         [0038]    The operation for causing the picture quality to be deteriorated corresponding to the number of times of the reproducing operation is performed corresponding to a flow chart shown in FIG. 3. This operation is performed by executing a control program stored in the ROM  21  by the microcomputer  20 . While digital video data as contents is being written to the data area  14 B of the magnetic disc medium  11 , the number of times of the retry operation is initialized (at step  401 ). When digital video data is reproduced, it is determined for what time the retry operation has been performed (at step  402 ). When the retry operation is performed first time (at step S 403 ), the retry operation against error is performed a maximum number of times that has been set in the initialization (at step  404 ). When the video data is reproduced at second time (at step  405 ), the retry operation against error is executed for (maximum number of times−1) (at step  406 ). When the video data is reproduced at n-th time, the maximum number of times of the retry operation is decremented by (n−1). After the video data is reproduced, the number of times of the reproducing operation is incremented and recorded to a predetermined record area (for example, the system area  14 A) (at step  407 ).  
         [0039]    The number of times of the retry operation may be identification code. Alternatively, the reproducing operation may be restricted. When a magnetic disc that can be reproduced up to two times is required, after the reproducing operation is completed second time (at step  407 ), reproduction prohibition code is recorded. When the reproducing operation is performed next time, if it is determined whether or not the reproduction prohibition code has been recorded at step  402 , the reproducing operation is not performed.  
         [0040]    Thus, as the number of times of the reproducing operation is increased, the number of times of the retry operation is decremented. As a result, the same effect as the deterioration of the picture quality corresponding to the increase of the number of times of the reproducing operation for video data of an analog VCR can be achieved. In addition, after the reproducing operation is performed for a predetermined number of times, a strong copy protect function can be accomplished.  
         [0041]    The operation corresponding to the flow charts shown in FIGS. 2 and 3 can be accomplished by a conventional magnetic disc  1 B shown in FIG. 4. In the magnetic disc  1 B shown in FIG. 4, only a magnetic disc medium  11 , a read/write head  12 , and a read/write amplifier circuit  13  are enclosed in the disc enclosure  2 . In other words, a spindle motor driver  16 , a VCM driver  17 , a read/write channel circuit  18 , a disc controller  19 , a microcomputer  20 , and a ROM  21  are not enclosed in the disc enclosure  2 B.  
         [0042]    As was described above, according to the present invention, since all the magnetic disc medium on which data is recorded and the circuit that processes a signal that is read from the magnetic disc medium area enclosed, a hacker cannot connect a probe to the circuit. Thus, the signal can be prevented from being illegally read and copied. If he or she opens the enclosure and connects a probe to the circuit, the magnetic disc and the read/write head are exposed to dust and gas. Thus, since a read error takes place, data cannot be correctly read.  
         [0043]    In addition, according to the present invention, only when the authentication code recorded in the magnetic disc device is matched with the authentication code that is input from the outside, data is read and output to the outside. Thus, only the reproducing device that supplies valid authentication code from the outside to the magnetic disc device can reproduce data. Consequently, only a user who has such a reproducing device can reproduce data. Thus, users who do no have such reproducing devices can not reproduce data. As a result, data can be prevented from being illegally copied.  
         [0044]    In addition, according to the present invention, whenever the reproducing operation is performed, the maximum number of times of the retry operation against error is decremented. Thus, when the copy operation is performed a plurality of times, the error rate of the reproduced data increases, thereby deteriorating the quality of the copied data. As a result, many copies can be prevented from being created.  
         [0045]    In addition, according to the present invention, since the number of times of the reproducing operation is limited, many copies can be prevented from being created.  
         [0046]    Although the present invention has been shown and described with respect to the best mode embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions, and additions in the form and detail thereof may be made therein without departing from the spirit and scope of the present invention.