Abstract: In one embodiment, a magnetic disk drive includes a magnetic disk having data tracks, a magnetic head, a motion mechanism for moving the magnetic head, and a controller. The controller adds a value to a rewrite parameter for a rewrite region based on a number of writes to data tracks related to the rewrite region, the value is chosen to reflect a degree of influence the number of writes have on the rewrite region, and the magnetic head rewrites data of the rewrite region when the rewrite parameter is greater than a threshold. In another embodiment, a method includes writing data tracks in a rewrite region, defining values reflecting a degree(s) of influence on the rewrite region, adding the values to a rewrite parameter upon writing data to the data tracks, determining that the rewrite parameter has reached or exceeded a threshold and rewriting data in the rewrite region.

Abstract: Embodiments of the invention control a recovery procedure effectively in accordance with write conditions. In one embodiment, the data to be written into a sector includes not only user data but also recording condition data, which indicates the temperature prevalent during a write. If a data read is not accurately performed, a recovery procedure is executed. If a data read is accomplished by a retry and the temperature prevalent during a write is lower than predetermined, it is concluded that the employed medium is nondefective. Thus, the read data is rewritten into the same sector without being stored in a spare area. This prevents the spare area from being unnecessarily consumed.

Abstract: A method of changing a program for controlling a disk drive that includes an EEPROM. The method includes storing a program block to a disk area such that the program block is associated with a second area for storing the program block that is not utilized for a read operation from the disk area. The method also includes storing a program block that is associated with a first area to an area that includes at least a portion of the second area in the EEPROM such that the first area contained a program block that is utilized for a read operation from the disk area. In addition, the method includes changing the program block in the first area after storing to the second area. Moreover, the method includes storing to the second area the program block that is not utilized for a read operation from the disk area after storing to the first area.

Abstract: Embodiments of the invention improve utility of a magnetic disk drive in which a head is retracted if the magnetic disk drive is in a dropping state. In one embodiment, an HDC/MPU provided in a magnetic disk drive judges whether the magnetic disk drive is in a dropping state based on an output from an acceleration sensor which may detect an acceleration and performs a retraction operation of a head. After the HDC/MPU judges that a drop is occurring, the HDC/MPU detects whether the drop judgment is incorrect according to whether a shock sensor detects a shock occurrence and changes the drop judgment condition based on a detection history of detected incorrect judgments.

Abstract: Embodiments of the invention control a recovery procedure effectively in accordance with write conditions. In one embodiment, the data to be written into a sector includes not only user data but also recording condition data, which indicates the temperature prevalent during a write. If a data read is not accurately performed, a recovery procedure is executed. If a data read is accomplished by a retry and the temperature prevalent during a write is lower than predetermined, it is concluded that the employed medium is nondefective. Thus, the read data is rewritten into the same sector without being stored in a spare area. This prevents the spare area from being unnecessarily consumed.

Abstract: Embodiments of the invention improve the efficiency of communication processing between a host and a storage device. In one embodiment, a data processing system includes a storage device and a host. The host gives the storage device an instruction to perform specified processing, and an instruction as to whether or not a completion notification of the instructed processing is to be transmitted to the host. If the host instructs the storage device to transmit a processing completion notification, the storage device transmits the completion notification to the host. On the other hand, if the host instructs the storage device not to transmit a processing completion notification, the storage device does not transmit the completion notification to the host.

Abstract: A recording drive waveform adjusting method for manufacturing a master disc is provided. The method includes forming an exposed area in an inorganic resist layer for test exposure by irradiating a master disc having the inorganic resist layer with laser light of a recording power based on a recording drive waveform according to a test recording signal. The method also includes obtaining reflected-light information by irradiating the exposed area formed in the test exposure with laser light of a reproducing power, determining whether the recording drive waveform is appropriate by using the reflected-light information, and correcting the recording drive waveform if the recording drive waveform is determined to be inappropriate in the determination.

Abstract: Embodiments of the invention improve utility of a magnetic disk drive in which a head is retracted if the magnetic disk drive is in a dropping state. In one embodiment, an HDC/MPU provided in a magnetic disk drive judges whether the magnetic disk drive is in a dropping state based on an output from an acceleration sensor which may detect an acceleration and performs a retraction operation of a head. After the HDC/MPU judges that a drop is occurring, the HDC/MPU detects whether the drop judgment is incorrect according to whether a shock sensor detects a shock occurrence and changes the drop judgment condition based on a detection history of detected incorrect judgments.

Abstract: Embodiments of the invention control a recovery procedure effectively in accordance with write conditions. In one embodiment, the data to be written into a sector includes not only user data but also recording condition data, which indicates the temperature prevalent during a write. If a data read is not accurately performed, a recovery procedure is executed. If a data read is accomplished by a retry and the temperature prevalent during a write is lower than predetermined, it is concluded that the employed medium is nondefective. Thus, the read data is rewritten into the same sector without being stored in a spare area. This prevents the spare area from being unnecessarily consumed.

Abstract: Embodiments of the invention provide an interface circuit that is capable of reducing the power consumption, which may be increased by a shoot-through current, and provide an electronic device having such an interface circuit. In one embodiment, an interface circuit exchanges signals with another electronic device via a signal transmission line. The interface circuit includes a switch for pulling up the signal transmission line and a switch for pulling down the signal transmission line. While a pull-up or pull-down is performed, the interface circuit detects the potential level of the signal transmission line to determine whether the signal transmission line is pulled down or pulled up by the other electronic device. If the signal transmission line is not pulled down/pulled up by the other electronic device, the interface circuit exercises pull-down/pull-up control.

Abstract: Data is arranged to one block obtained after a CIRC process so that a predetermined data pattern is recorded into a predetermined portion on a disc. By tracing back an encoding step of a Cross-Interleave Reed-Solomon Code (CIRC), a layout of recording data of one block before the CIRC process for allowing the predetermined data pattern to be recorded into the predetermined portion is obtained. An error correcting process of a CD-ROM mode 1 is executed. If a position of a parity coincides with data for forming the predetermined data pattern, a value of user data of an encoding sequence to form the parity is changed. After error correction encoding of a CD-ROM is executed, encoding of the CIRC is executed to the recording data of one block.

Abstract: Embodiments of the invention improve utility of a magnetic disk drive in which a head is retracted if the magnetic disk drive is in a dropping state. In one embodiment, an HDC/MPU provided in a magnetic disk drive judges whether the magnetic disk drive is in a dropping state based on an output from an acceleration sensor which may detect an acceleration and performs a retraction operation of a head. After the HDC/MPU judges that a drop is occurring, the HDC/MPU detects whether the drop judgment is incorrect according to whether a shock sensor detects a shock occurrence and changes the drop judgment condition based on a detection history of detected incorrect judgments.

Abstract: When a host apparatus transfers/swaps stored information between user sectors in a storage device for the purpose of defragmentation or the like, the storage device is allowed to perform the data transfer or swap without transmission between the host apparatus and the storage device after the command is received by the storage device; and consistency in stored information identification is maintained between the host apparatus and the storage device even if the operation is interrupted. In one embodiment, information stored in the destination user sector LBA(Y) is copied to the dummy sector LBA(D), its entry is written in the mapping table RDM, information stored in the source user sector LBA(X) is copied to LBA(Y), and then the RDM entry is erased.

Abstract: A contour emphasizing circuit which comprises a contour pick-up unit 10 for picking up a contour component HE from an input luminance signal Y, a level judging unit 15 for judging the luminance level of the input luminance signal Y, a coefficient control unit 17 for changing the coefficient in a plurality of steps depending upon a judgment signal and multiplying the contour component HE by the coefficient to output the product, and an adder 14 for adding the contour component outputted from the coefficient control unit 17 to the input luminance signal Y to output an emphasized-contour luminance signal. The coefficient to be multiplied by the contour component HE is changed in a plurality of steps depending upon the luminance level of the input luminance signal Y, and the contour component HE to be added to the input luminance signal Y is controlled to have a magnitude appropriate to the luminance level of the input luminance signal Y.

Abstract: A recording method for converting m-bit data into n-bit (where n>m) bit data whose run length is restricted and recoding the converted data on a recording medium, the recording method comprising the steps of when at least preceded data is data containing a special data pattern, lightening the restriction of the run length; and recording data so that the cumulative value of DC components per unit time increase when the data is reproduced in the state that the run length is restricted.

Abstract: Embodiments in accordance with the present invention help a disk drive to effectively cope with a data address mark detection error. In one embodiment, a data sector is provided with plural data address marks and an read/write (RW) channel reads out the data sector using part of those data address marks. Each divisional section of a split sector has two data address marks and the RW channel uses one of the two data address marks. A data address mark to be used is specified by a register. When an error occurs in detecting a data address mark, its position is stored in a register. Based on the error position, an error recovery processing section stores, in the register, a data address mark to be used in a next retry.

Abstract: A recording method for converting m-bit data into n-bit (where n>m) data whose run length is restricted and recording the converted data on a recording medium, the recording method comprising the step of selecting first n-bit data according to an immediately preceded n-bit data, first n-bit data immediately followed thereby, and second n-bit data immediately followed thereby so that the cumulative value of DC components per unit time becomes small.

Abstract: A recording method includes the steps of generating recording data in such a manner that, when m-bit data is converted into a data symbol of n bits (m<n), and connection bits such that the summed value of DC components per unit time decreases are selected from among a plurality of connection bits and are added after the m-bit data symbol, the connection bits differing from connection bits which are added when the n-bit data symbol is a data symbol other than the special data symbol are added to generate recording data; and recording the generated recording data on a recording medium.

Abstract: A recording method, wherein, when a certain portion of main data is recorded by being encoded by a first encoding method and the other portions of the main data is recorded by being encoded by a second encoding method, an encoding process is performed by the first encoding method so that, when data which is recorded in such a manner that the data encoded by the first encoding method is decoded by a decoding method corresponding to the first encoding method, and thereafter, is further encoded by the second encoding method, is decoded by a decoding method corresponding to the second encoding method, the sum value of DC components per unit time increases.

Abstract: Six record areas for predetermined data that has been encoded and digitally modulated are formed in a data record area on a disc. The record areas have different offset compensation amounts. The offset compensation amounts allow all offset amounts that may take place in an error correction code encoder to be compensated. Thus, regardless of the offset amount generated by the error correction code encoder, encoded and modulated data that has been generated by the conventional EFM modulating system and recorded in one of the record areas securely causes DSV to deviate. Each of the record areas is set to a sufficient length that allows the effect of which DSV deviates to be recognized.