Abstract: According to one embodiment, a magnetic disk device includes a first disk having a first user data region and a first system area, a second disk having a second user data region and a second system area, a first head that writes data to the first disk, a second head that writes data to the second disk, a first actuator having the first head, a second actuator having the second head, a first controller that controls the first disk, the first head, and the first actuator, and a second controller that controls the second disk, the second head, and the second actuator, wherein the first controller records first information related to the first head and the first disk in the second system area.

Abstract: According to one embodiment, a magnetic disk device includes a first disk having a first user data region and a first system area, a second disk having a second user data region and a second system area, a first head that writes data to the first disk, a second head that writes data to the second disk, a first actuator having the first head, a second actuator having the second head, a first controller that controls the first disk, the first head, and the first actuator, and a second controller that controls the second disk, the second head, and the second actuator, wherein the first controller records first information related to the first head and the first disk in the second system area.

Abstract: A channel circuit includes: a detecting module configured to sample a signal amplitude of a reproduced signal of a single-frequency pattern written on a medium, and to detect an amplitude change that is lower or higher than a threshold; and a judgement module configured to judge whether the reproduced signal is decodable by a decoding circuit or not based on a result of detection by the detecting module.

Abstract: A communication control apparatus transmits data to an other communication control apparatus and receives a notification as to whether the data has normally been received or not from the other communication control apparatus. The communication control apparatus includes setting changing means for changing setting of a transmission circuit when reception error which is a notification that the data has not normally been received is received from the other communication control apparatus.

Abstract: In an information storage device adapted to use a power supply supplied from an interface or a battery, a voltage input from the power supply is monitored in each time the power consumption of the device is gradually increased upon connection of the power supply, so that the power consumption or the function of the device is limited based on the result of monitoring. Alternatively, a voltage or a current input from the power supply during operation of the device is monitored, so that the power consumption or the function of the device is limited based on the result of monitoring.

Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.

Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.

Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.

Abstract: In an information record/replay apparatus for writing information to, and reading information from, a disk medium while communicating with a host apparatus by way of an interface having a first transfer mode and a second transfer mode with a lower transfer speed than the first transfer mode, an operation for writing to the disk medium is controlled by assigning a higher rotation speed or shorter seek time than that of the first transfer mode when the second transfer mode is specified.

Abstract: A predetermined electric current is supplied to coil by changing a pulse width of a voltage applied to the coil according to a current instruction value. An electric current which flows through the coil is detected; the thus-detected current value is compared with the current instruction value; the voltage applied to the inductance device is turned on/off according to the comparison result; and an off time for which application of the voltage to the coil is interrupted is controlled according to the current instruction value.

Abstract: In an information storage device adapted to use a power supply supplied from an interface or a battery, a voltage input from the power supply is monitored in each time the power consumption of the device is gradually increased upon connection of the power supply, so that the power consumption or the function of the device is limited based on the result of monitoring. Alternatively, a voltage or a current input from the power supply during operation of the device is monitored, so that the power consumption or the function of the device is limited based on the result of monitoring.

Abstract: An apparatus automatically controls the laser power of the light source by the feedback output of the APC detector and prevents the increase of laser power due to an abnormality of the APC detector. The automatic power control unit controls the drive amount of the light source by the detection output of the APC detector, which monitors the emission power of the light source, measures the relationship between the APC drive instruction amount and the detection output of the APC detector, and compares this inclination with the inclination at normal time. Also the automatic power control unit compares the error values before and after APC, and detects the change of the quantity of returned light during a predetermined period. As a result, data destruction due to separation, deviation, contamination or deterioration of the APC detector can be prevented effectively.

Abstract: A predetermined electric current is supplied to an inductance device by changing a pulse width of a voltage applied to the inductance device according to a current instruction value. An electric current which flows through the inductance device is detected; the thus-detected current value is compared with the current instruction value; the voltage applied to the inductance device is turned on/off according to the comparison result; and an off time for which application of the voltage to the inductance device is interrupted is controlled according to the current instruction value.

Abstract: An offset measuring unit receives a servo error signal E1 in which a change in an offset caused by a change in an amount of reflection light directly appears and which does not pass through a filter, and measures an offset amount in the servo error signal which is caused by a change in the amount of reflection light. A correction amount calculating unit calculates a correction amount to cancel out the offset amount and outputs the correction amount to an offset correcting circuit for an offset generating period so as to perform correction.

Abstract: An offset measuring unit receives a servo error signal E1 in which a change in an offset caused by a change in an amount of reflection light directly appears and which does not pass through a filter, and measures an offset amount in the servo error signal which is caused by a change in the amount of reflection light. A correction amount calculating unit calculates a correction amount to cancel out the offset amount and outputs the correction amount to an offset correcting circuit for an offset generating period so as to perform correction.

Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.

Abstract: A method of adjusting a motor driving device which performs current-feedback PWM drive, the motor driving device, and an information storage device are provided. According to the present invention, a drive circuit is turned off by a control circuit, and a target current indication signal is gradually increased. The content of a register which stores the result of comparison between the output signal of a comparator circuit and the target current indication signal is then detected. If the content of the register is "1", i.e., if the output signal of the current sense circuit is smaller than a target current indication signal, the target current indication signal immediately before the output of the comparator circuit reaches "1" is stored as the reference value of the target current indication signal.