Abstract: Embodiments of the present invention help to perform appropriate servo control in response to detected vibration in a disk drive device having a vibration sensor. In an embodiment of the present invention, an HDD switches a correction servo mode to perform vibration correction in head positioning and a normal servo mode not to perform the vibration correction. The HDD performs servo positioning in either one of the serve modes and determines servo positioning accuracy in the servo mode from the measured positional error signal. The HDD obtains data indicating the servo positioning accuracy in the other servo mode from a table. The HDD compares the accuracy in the two servo modes and selects the servo mode with higher accuracy. The table contains previous measurements on servo positioning accuracy in the servo modes.

Abstract: Embodiments of the present invention efficiently perform servo correction for prevention of propagation of a position error in a radial direction in self servo write (SSW). According to one embodiment, in SSW, a target position of a reference track TO in writing a servo write track TN is corrected. The target position is represented as a target value of a position signal calculated from a signal read by a read element. A signal indicating a deviation (a position error) from the target position (the target value) is referred to as PES. The SSW in this example performs correction of target positions in respective tracks using an impulse response of a servo system. Consequently, it is possible to efficiently and effectively prevent the propagation of position error in the SSW.

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 present invention help to perform appropriate servo control in response to detected vibration in a disk drive device having a vibration sensor. In an embodiment of the present invention, an HDD switches a correction servo mode to perform vibration correction in head positioning and a normal servo mode not to perform the vibration correction. The HDD performs servo positioning in either one of the serve modes and determines servo positioning accuracy in the servo mode from the measured positional error signal. The HDD obtains data indicating the servo positioning accuracy in the other servo mode from a table. The HDD compares the accuracy in the two servo modes and selects the servo mode with higher accuracy. The table contains previous measurements on servo positioning accuracy in the servo modes.

Abstract: Embodiments of the invention reduce the effect of the rotational jitters to write a pattern in more accurate timing in self-writing a pattern on a magnetic disk. In an embodiment of the invention, respective patterns in N sectors are first written on an inner circumferential side track as reference patterns with a default clock frequency and a default clock number (a writing interval clock number between respective patterns). The respective reference patterns are then read out plural times for measuring intervals thereof to determine an average value of intervals between the respective sectors. Using the value, a target value is calculated in each sector, which is used in wiring new patterns on the outer circumferential side at even intervals. Then, the respective reference patterns on the inner circumferential side track are read out while the new patterns are written on the outer circumferential side.

Abstract: Embodiments in accordance with the present invention relate to suppressing effects of the rotational jitter of a rotating medium during self-writing of patterns on the medium. In one embodiment, patterns are written on a track TE first. While a clock frequency is modulated using the difference between the readout time and target time of each pattern PE on the track TE, patterns PF are written on a track TF after a calculated delay time from the readout of each pattern PE. During pattern writing on the track TF, any timing errors of the patterns PE are stored into memory. While the target time for each pattern PF on the track TF is being corrected using the stored timing errors of the patterns PE and the clock frequency is being modulated using the difference between the readout time and corrected target time of each pattern PF, patterns PG are written on a track TG after a calculated delay time from the readout of each pattern PF.

Abstract: Embodiments of the present invention provide a method of forming an initial servo-pattern for self servowrite, insusceptible to constraints of an output resolution of a driver circuit for driving an actuator, and a dynamic range. According to one embodiment, a cluster pattern made up of pattern blocks, each including a burst pattern, is written by use of a write element by pressing a head-support mechanism to a crash-stop, and a pattern block is newly written with a read element in states of being positioned at an inner peripheral side edge of the cluster pattern, an outer peripheral side edge thereof, and the center of two burst patterns included in the cluster pattern, respectively, thereby increasing a width of the cluster patterns in stages, so that an initial servo pattern for use in a propagation action is formed.

Abstract: Embodiments of the present invention efficiently perform servo correction for prevention of propagation of a position error in a radial direction in self servo write (SSW). According to one embodiment, in SSW, a target position of a reference track TO in writing a servo write track TN is corrected. The target position is represented as a target value of a position signal calculated from a signal read by a read element. A signal indicating a deviation (a position error) from the target position (the target value) is referred to as PES. The SSW in this example performs correction of target positions in respective tracks using an impulse response of a servo system. Consequently, it is possible to efficiently and effectively prevent the propagation of position error in the SSW.

Abstract: Embodiments in accordance with the present invention suppress an adverse influence on a pattern of a magnetic disk due to its rotational jitter and write the pattern at more accurate timing. In accordance with one embodiment, a hard disk controller/microprocessing unit (HDC/MPU) controls a clock frequency of a data clock generation circuit so that a rotational jitter of the magnetic disk be compensated when writing and reading user data. The HDC/MPU expects a detection timing of next adjacent servo sector using an error between an actual detection timing and an expected detection timing of a servo sector which has already been detected. The HDC/MPU controls the clock frequency using the expected timing and writes and reads user data between current servo sector and next adjacent servo sector according to the clock signal.

Abstract: Embodiments of the invention efficiently conduct servo corrections for preventing error propagation during SSW. In an example of the present invention, a servo position signal generator generates a servo position signal indicative of the current position of a read element on the basis of a servo signal from a servo channel. A target position generator generates correction data from multiply and add operations between the PES generated when the track that the read element is following is written, and pre-registered correction coefficients. A correction target position is generated from the correction data and a reference target position, and then output to a position error calculator. The position error calculator generates a position error signal (PES) from the servo position signal and the target position signal, and outputs PES to a servo controller.

Abstract: Embodiments in accordance with the present invention relate to suppressing effects of the rotational jitter of a rotating medium during self-writing of patterns on the medium. In one embodiment, patterns are written on a track TE first. While a clock frequency is modulated using the difference between the readout time and target time of each pattern PE on the track TE, patterns PF are written on a track TF after a calculated delay time from the readout of each pattern PE. During pattern writing on the track TF, any timing errors of the patterns PE are stored into memory. While the target time for each pattern PF on the track TF is being corrected using the stored timing errors of the patterns PE and the clock frequency is being modulated using the difference between the readout time and corrected target time of each pattern PF, patterns PG are written on a track TG after a calculated delay time from the readout of each pattern PF.

Abstract: Embodiments of the invention reduce the effect of the rotational jitters to write a pattern in more accurate timing in self-writing a pattern on a magnetic disk. In an embodiment of the invention, respective patterns in N sectors are first written on an inner circumferential side track as reference patterns with a default clock frequency and a default clock number (a writing interval clock number between respective patterns). The respective reference patterns are then read out plural times for measuring intervals thereof to determine an average value of intervals between the respective sectors. Using the value, a target value is calculated in each sector, which is used in wiring new patterns on the outer circumferential side at even intervals. Then, the respective reference patterns on the inner circumferential side track are read out while the new patterns are written on the outer circumferential side.

Abstract: Embodiments of the invention efficiently conduct servo corrections for preventing error propagation during SSW. In an example of the present invention, a servo position signal generator generates a servo position signal indicative of the current position of a read element on the basis of a servo signal from a servo channel. A target position generator generates correction data from multiply and add operations between the PES generated when the track that the read element is following is written, and pre-registered correction coefficients. A correction target position is generated from the correction data and a reference target position, and then output to a position error calculator. The position error calculator generates a position error signal (PES) from the servo position signal and the target position signal, and outputs PES to a servo controller.

Abstract: A correction mechanism for use in a data storage system that allows data to be read even if the recorded data has been phase shifted.

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: A correction mechanism for use in a data storage system that allows data to be read even if the recorded data has been phase shifted.