Abstract: A head position estimator estimates the present position of a head relative to a recording medium, an LBA calculator for calculating positions of a data block to be read next and other data blocks existing before and after the data block, and a moving destination determiner for determining a data block at which the time required to move the head is the shortest, as a data block to be read next, on the basis of the present position of the head, which has been estimated by the head position estimator, and the positions of the respective data blocks, which have been calculated by the LBA calculator.

Abstract: A file is transferred directly between a parent magnetic-disk device and a child magnetic-disk device. In one embodiment, a parent magnetic-disk device has a host-mode execution program, whereas a child magnetic-disk device is capable operating in a device mode as is the case with an ordinary magnetic-disk device. The parent magnetic-disk device has an operating-mode-setting unit including a special-purpose jumper block. An MPU employed in the parent magnetic-disk device executes the host-mode execution program to put the parent magnetic-disk device in a host mode. At an activation time, the MPU refers to the logic of the special jumper block to start an operation in the host mode. The MPU controls the parent magnetic-disk device to directly transfer a file to the child magnetic-disk device. Thus, the file can be transferred between the parent and child magnetic-disk devices without intervention by a host computer.

Abstract: Embodiments of the invention reduce consumption power of a data storage device. In one embodiment, an HDD according to the embodiment selectively switches a serial interface among other circuits to a power-save mode. The HDD receives a command from a host, and, in a command execution sequence thereof, sets and keeps the serial interface in the power-save mode for at least a partial period of time during which no sending and receiving of data resulting from serial data communication with the host exists. Further, in responding to completion of execution of the command, the HDD switches the serial interface to the power-save mode.

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: Embodiments of the invention realize a power-save mode which prevents reduction in performance of a data storage device. The HDD as an embodiment of the present invention, upon receiving a request for switching to a power-save mode (PMREQ) from the host, judges whether the serial interface should be switched to the power-save mode based on the execution status of the command. When the HDD has determined not to switch the serial interface to the power-save mode, the HDD transmits a negative response (PMNACK) to the host and keep the serial interface in the active mode. By denying switching to a power-save mode when data transfer is executed within a short period of time, etc., it is possible to prevent reduction in performance of the data storage device.

Abstract: Embodiments of the invention improve power management in a data storage device which executes serial data communication with a host. In one embodiment, a HDD executes a reset process from a sleep mode (clock inactive) as being triggered by a control signal that is not based on a clock from the host. Even during a period in which the system clock is suspended, the HDD is able to receive the control signal from the host. In responding to the control signal and by activating a circuit required for serial data transmission, the HDD is enabled to receive a software reset command from the host via a serial data transmission circuit. With such an arrangement, the HDD can receive the software reset command from the host, and in responding to the reception of the command, the HDD can be reset to the normal active mode.

Abstract: Embodiments of the invention reduce consumption power of a data storage device. In one embodiment, an HDD according to the embodiment selectively switches a serial interface among other circuits to a power-save mode. The HDD receives a command from a host, and, in a command execution sequence thereof, sets and keeps the serial interface in the power-save mode for at least a partial period of time during which no sending and receiving of data resulting from serial data communication with the host exists. Further, in responding to completion of execution of the command, the HDD switches the serial interface to the power-save mode.

Abstract: A file is transferred directly between a parent magnetic-disk device and a child magnetic-disk device. In one embodiment, a parent magnetic-disk device has a host-mode execution program, whereas a child magnetic-disk device is capable operating in a device mode as is the case with an ordinary magnetic-disk device. The parent magnetic-disk device has an operating-mode-setting unit including a special-purpose jumper block. An MPU employed in the parent magnetic-disk device executes the host-mode execution program to put the parent magnetic-disk device in a host mode. At an activation time, the MPU refers to the logic of the special jumper block to start an operation in the host mode. The MPU controls the parent magnetic-disk device to directly transfer a file to the child magnetic-disk device. Thus, the file can be transferred between the parent and child magnetic-disk devices without intervention by a host computer.

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: A head position estimator estimates the present position of a head relative to a recording medium, an LBA calculator for calculating positions of a data block to be read next and other data blocks existing before and after the data block, and a moving destination determiner for determining a data block at which the time required to move the head is the shortest, as a data block to be read next, on the basis of the present position of the head, which has been estimated by the head position estimator, and the positions of the respective data blocks, which have been calculated by the LBA calculator.

Abstract: The signal output device of the present invention comprises of a driver circuit and a controller. The signal sending method of the present invention sets any one of a plurality of the different sending rates. The method also includes setting a slew rate of the driver circuit to a standard value that is in accordance with the predetermined data transfer rate, thereby starting signal transmission. The next step involves determining whether or not a data transfer error occurrence rate is below a predetermined allowable threshold. Then, changes in the slew rate of the driver circuit are made if the data transfer error occurrence rate is determined to be over the allowable threshold. Next, a search for a slew rate value that can decrease the data transfer error occurrence rate below the allowable threshold or decrease the data transfer error occurrence rate is performed. The new slew rate value is set as a new standard value.

Abstract: A slew rate of a data signal is controlled to be smaller than a slew rate of a strobe signal by independently controlling the slew rate of the data signal and slew rates of control signals by controlling the strobe signal with the slew rate controller of the driver. The gradient of the signal waveform is controlled in the transition times of the strobe signal to be greater than that of the data signal.

Abstract: The signal output device of the present invention comprises of a driver circuit and a controller. The signal sending method of the present invention sets any one of a plurality of the different sending rates. The method also includes setting a slew rate of the driver circuit to a standard value that is in accordance with the predetermined data transfer rate, thereby starting signal transmission. The next step involves determining whether or not a data transfer error occurrence rate is below a predetermined allowable threshold. Then, changes in the slew rate of the driver circuit are made if the data transfer error occurrence rate is determined to be over the allowable threshold. Next, a search for a slew rate value that can decrease the data transfer error occurrence rate below the allowable threshold or decrease the data transfer error occurrence rate is performed. The new slew rate value is set as a new standard value.

Abstract: Methods and apparatus are described for a data transfer unit between a storage unit and a host, wherein a slower data transfer rate is established when a predetermined error is detected. In one embodiment the cyclicity of the error occurrence calculated and a wait is inserted between data to avoid transferring data at the calculated cyclicity point of the detected error. Optionally the data transfer unit may return the data transfer rate to the original data transfer rate or state after a predetermined time has elapsed, after a predetermined number of commands have been received, after a predetermined amount of data have been transferred, or by combination of these.

Abstract: Methods and apparatus are described for a data transfer unit between a storage unit and a host, wherein a slower data transfer rate is established when a predetermined error is detected. In one embodiment the cyclicity of the error occurrence calculated and a wait is inserted between data to avoid transferring data at the calculated cyclicity point of the detected error. Optionally the data transfer unit may return the data transfer rate to the original data transfer rate or state after a predetermined time has elapsed, after a predetermined number of commands have been received, after a predetermined amount of data have been transferred, or by combination of these.