Abstract: Embodiments in accordance with the present invention provide a disk unit capable of restricting access to data stored in the recording medium depending on users. In one embodiment, the user enters a password into a host computer. This password is transferred to a password verification section. Then, the password verification section checks whether the password coincides with any one of authentication passwords stored in an authentication password storage section. If the password coincides with any one of the passwords, the password verification section supplies an authentication signal to an operation mode control section. The operation mode control section supplies an operation mode signal to a controller by receiving the authentication signal. The controller controls execution of the operation mode according to the operation mode signal.

Abstract: A method for writing data to a disk drive. The method includes: receiving a write command; and, determining whether a beginning and an end of a rewrite area specified by the write command agree with boundaries of large-sized data sectors on a disk. The method also includes: reading head and tail data sectors and making a backup of the head and tail data sectors in first and second non-volatile memory areas, respectively, if the beginning of the rewrite area does not agree with the boundaries. The method includes starting a rewrite of the rewrite area after completing backups into first and second non-volatile memory areas. Moreover, the method includes: determining a state stage by using data in first, second, third and fourth non-volatile memory areas if a power shut-down occurs during execution of the write command; and, executing a recovery process in accordance with the determined state stage.

Abstract: Embodiments of the present invention help to securely manage a data cryptographic key in a data storage device. In an embodiment of the present invention, a cryptographic processor for encrypting and decrypting data is located between a host interface and a memory manager. In parts of the hard disk drive (HDD), except for the host interface, the HDD handles user data in an encrypted state. A data cryptographic key which the cryptographic processor uses to encrypt and decrypt the user data is encrypted and stored in a magnetic disk. A multiprocessing unit (MPU) decrypts the data cryptographic key using a password and a random number to supply it to the cryptographic processor. Using the password and the random number, the HDD can manage the data cryptographic key with more security.

Abstract: A magnetic disk drive is provided capable of reducing a processing load even in a mode of, for example, reproduction during recording. In one embodiment, a magnetic disk drive includes a storage unit for storing certificate information that relates to the magnetic disk drive and corresponds to a root key of a certification organization. The certificate information is used on the host side to perform authentication processing of the magnetic disk drive.

Abstract: A method for writing data to a disk drive. The method includes: receiving a write command; and, determining whether a beginning and an end of a rewrite area specified by the write command agree with boundaries of large-sized data sectors on a disk. The method also includes: reading head and tail data sectors and making a backup of the head and tail data sectors in first and second non-volatile memory areas, respectively, if the beginning of the rewrite area does not agree with the boundaries. The method includes starting a rewrite of the rewrite area after completing backups into first and second non-volatile memory areas. Moreover, the method includes: determining a state stage by using data in first, second, third and fourth non-volatile memory areas if a power shut-down occurs during execution of the write command; and, executing a recovery process in accordance with the determined state stage.

Abstract: A data-storage device with a security function for user data stored in a data-storage medium. The data-storage device includes: the data-storage medium for storing data; an authentication processing section for performing an authentication process with a key obtained from a host; an error correction circuit for performing error correction in reading data at an address designated by a read command from a host which has been recognized as an authorized user for analysis access by the authentication processing section; and an analysis processing section for generating data indicating the positions of the error correction and transferring the data to the host.

Abstract: Embodiments of the present invention help to securely manage a data cryptographic key in a data storage device. In an embodiment of the present invention, a cryptographic processor for encrypting and decrypting data is located between a host interface and a memory manager. In parts of the hard disk drive (HDD), except for the host interface, the HDD handles user data in an encrypted state. A data cryptographic key which the cryptographic processor uses to encrypt and decrypt the user data is encrypted and stored in a magnetic disk. A multiprocessing unit (MPU) decrypts the data cryptographic key using a password and a random number to supply it to the cryptographic processor. Using the password and the random number, the HDD can manage the data cryptographic key with more security.

Abstract: Embodiments of the invention increase the convenience of a magnetic disk drive for portable use by shortening a period of time required to record a large amount of data, and by increasing the reproduction time, in the magnetic disk drive. In one embodiment, an area between servo data parts is interpolated by servo data parts, each of which stores a burst signal, so that the allocation density of a burst signal is made k times. At the time of write operation in which data is written, only the servo data parts are made use of to perform the servo control while a disk is driven at high rotational speed so as to reduce the recording time. At the time of read operation in which data is reproduced, the servo data parts are made use of to ensure the required precision of the servo control at low rotational speed that is 1/k of the rotational speed at the time of write operation. The reproduction at low rotational speed enables the reduction in power consumption.

Abstract: Embodiments of the invention increase the convenience of a magnetic disk drive for portable use by shortening a period of time required to record a large amount of data, and by increasing the reproduction time, in the magnetic disk drive. In one embodiment, an area between servo data parts is interpolated by servo data parts, each of which stores a burst signal, so that the allocation density of a burst signal is made k times. At the time of write operation in which data is written, only the servo data parts are made use of to perform the servo control while a disk is driven at high rotational speed so as to reduce the recording time. At the time of read operation in which data is reproduced, the servo data parts are made use of to ensure the required precision of the servo control at low rotational speed that is 1/k of the rotational speed at the time of write operation. The reproduction at low rotational speed enables the reduction in power consumption.

Abstract: Embodiments in accordance with the present invention provide a data recording device that is capable of easily managing, on a user basis, data key used for data encryption, and to provide a data management method thereof. According to one embodiment, a data encryption/decryption circuit performs the steps of: encrypting write data inputted from the host side, and then outputting the encrypted write data to the magnetic disk side; and decrypting read data inputted from the magnetic disk side, and then outputting the decrypted read data to the host side. A data-key management circuit manages a data key used to operate the data encryption/decryption circuit.

Abstract: Embodiments in accordance with the present invention relate to realizing content protection by enhancing data safety by detecting falsification of data stored in a storage device. A storage device in accordance with an embodiment of the present invention includes an HDA (Head Disk Assembly) and a controller, and a nonvolatile memory that is connected to the controller. When writing data on a hard disk from an external device, validity of access is authenticated. When the authentication is successful, a digest of the data to be written is generated by using a hush function. The generated digest is stored in the nonvolatile memory. When reading out data, a digest of the data to be read out is generated, and the digest stored in the nonvolatile memory is read out, followed by verification of whether or not the digests coincide with each other.

Abstract: Embodiments of the invention allow relatively simple circuits to provide a coding device capable of coding longer bit-length data suitably for disk apparatus and a decoding device capable of decoding the data coded by the coding device. In one embodiment, a coding device comprises: a coder which, based on an M bits code string, produces an (M+1) bits coded string where each of the plural bits which may appear in the M bits code string is limited in run length; a preprocessor which produces an M bits code string by removing (N?M) bits respectively from predefined (N?M) positions of an incoming N bits code string and outputs the M bits code string to the coder; and a postprocessor which produces and outputs an (N+1) bits code string by inserting the (N?M) bits, which are removed by the preprocessor, into predefined (N?M) respective insertion positions of the (M+1) bits coded string output from the coder.

Abstract: Embodiments in accordance with the present invention provide a disk unit capable of restricting access to data stored in the recording medium depending on users. In one embodiment, the user enters a password into a host computer. This password is transferred to a password verification section. Then, the password verification section checks whether the password coincides with any one of authentication passwords stored in an authentication password storage section. If the password coincides with any one of the passwords, the password verification section supplies an authentication signal to an operation mode control section. The operation mode control section supplies an operation mode signal to a controller by receiving the authentication signal. The controller controls execution of the operation mode according to the operation mode signal.

Abstract: A data discriminating unit includes a data discriminator and a sync signal discriminator. A data sync signal is detected for the bit string discriminated from the output of the sync signal discriminator, and the data is demodulated for the bit string discriminated from the output of the data discriminator, thereby optimizing the signal to a form suitable for discrimination and detection of the data sync signal and demodulation for data reproduction. As a result, the detection performance of the data sync signal can be improved while maintaining the data discrimination performance. A Viterbi decoder is used for discrimination by the data discriminator and the sync signal discriminator for the optimization thereby to optimize the number of states, the number of paths for state transition and the path memory length. A signal having no continuous inversions of the recording data is used as the data sync signal.

Abstract: A magnetic disk drive is provided capable of reducing a processing load even in a mode of, for example, reproduction during recording. In one embodiment, a magnetic disk drive includes a storage unit for storing certificate information that relates to the magnetic disk drive and corresponds to a root key of a certification organization. The certificate information is used on the host side to perform authentication processing of the magnetic disk drive.

Abstract: In a coding method which does not restrict a run length of “1” while data is recorded/reproduced, there are such a drawback that when an error correction is carried out, a total number of error data to be corrected is increased, and also errors of not-detectable data are increased. While data is coded, a continuous number of “1” contained in a code word is limited, and then an error correction is carried out inside a coding/decoding process operation. Thus, a recording/reproducing apparatus having a small number of decoding errors is available.

Abstract: A data sync signal detecting device for detecting a sync signal having sync signal detection errors. The detecting device applies the output data of a most-likelihood decoder to shift register bit cells. The data is sequentially shifted and held in the bit cells of the shift register. The bit cell outputs are separated into odd-numbered and even-numbered bit string and applied to first and second pattern matching circuits. The odd-numbered bit string is matched with “01001” by a first pattern matching circuit. The even-numbered bit string is matched with “01011” by a second pattern matching circuit. First and second matching results are applied to a coincidence number adder/majority decision circuit. When coincidence occurs, the matching result is “1”, and when non-coincidence occurs, the matching result is “0”. The coincidence number adder/majority decision circuit produces a sync signal detection output when the first or second matching result is “1”.

Abstract: Embodiments of the invention increase the convenience of a magnetic disk drive for portable use by shortening a period of time required to record a large amount of data, and by increasing the reproduction time, in the magnetic disk drive. In one embodiment, an area between servo data parts is interpolated by servo data parts, each of which stores a burst signal, so that the allocation density of a burst signal is made k times. At the time of write operation in which data is written, only the servo data parts are made use of to perform the servo control while a disk is driven at high rotational speed so as to reduce the recording time. At the time of read operation in which data is reproduced, the servo data parts are made use of to ensure the required precision of the servo control at low rotational speed that is 1/k of the rotational speed at the time of write operation. The reproduction at low rotational speed enables the reduction in power consumption.

Abstract: Embodiments of the invention allow relatively simple circuits to provide a coding device capable of coding longer bit-length data suitably for disk apparatus and a decoding device capable of decoding the data coded by the coding device. In one embodiment, a coding device comprises: a coder which, based on an M bits code string, produces an (M+1) bits coded string where each of the plural bits which may appear in the M bits code string is limited in run length; a preprocessor which produces an M bits code string by removing (N-M) bits respectively from predefined (N-M) positions of an incoming N bits code string and outputs the M bits code string to the coder; and a postprocessor which produces and outputs an (N+1) bits code string by inserting the (N-M) bits, which are removed by the preprocessor, into predefined (N-M) respective insertion positions of the (M+1) bits coded string output from the coder.

Abstract: When an error requiring a retry operation occurs, information concerning the error is stored every time. The information includes a sector number (or beginning sector number and number of sectors), the content of the command; a write or read designation, and the number of the times of error occurrence in the sector (or number of the times of retry operation), for example. In the case of recording information, like the prior art, information to be written which is stored in a buffer memory is held as is. Since the information concerning an error requiring a retry operation is stored, even though that error occurs repeatedly, a write and/or read operation of the next executable command to another track is executed without immediately switching to the retry operation. Thus, other commands are executed between the occurrence of the error requiring a retry operation and actual execution of the retry operation.