Abstract: Embodiments of the invention reduce a possibility that a head will collide with a medium when the clearance between the head and the medium is adjusted by using a medium, and sufficiently reduce the clearance even at an initial stage of accessing a data area. In one embodiment, a hard disk drive (HDD) switches a heater from OFF to ON in the specified timing after a seek mode is switched to a following mode. Specifically, for example, on the completion of seek operation, in the timing in which a head arrives at a target track, or in the timing in which an HDC/MPU enters the following mode, the heater is turned ON, and this state is kept unchanged until access to the target sector is made.

Abstract: Embodiments of the invention provide control of a disk data storage device to prevent off-track writing. In one embodiment, the SA acquires the CYLIDs and ADC Values generated from the SERVO SIGNALs acquired previously, and generates DACOUT which defines a driving current of the VCM driver. The SA monitors the DACOUT generated and determines whether the DACOUT is within a predefined range. If the DACOUT is outside the predefined range, data writing is inhibited. By monitoring the DACOUT, it is possible for the VCM driver to detect supply of an overcurrent to the VCM driver 210 beforehand, and off-track writing can thus be prevented.

Abstract: To provide a disk drive, a manufacturing method thereof, and a disk-drive controller which are capable of improving yield without increasing costs so significantly. When track-following control is performed, HDC detects the current position of a read/write head, based on the reproduced output of a servo sector from a channel unit, and makes a calculation of servo data by employing both an integral parameter corresponding to a target track to be read onto a RAM and the detected current position of the read/write head.

Abstract: A disk drive seek control system device to reduce track pitch. When data is recorded, an offset value is added to the position of a read head element along the width of a track corresponding to an offset &Dgr;w between the read head element and a write head element. The value of the offset depends on the yaw angle &thgr; of the head. When data is read, the position of the read head element is chosen to be either the position of the write head element during write operations, or the midpoint between the position of the write head element and the read head element during write operations, or the center of a track.

Abstract: In order to handle platter flutter in a hard disk operated at high speed (e.g. 10,000 RPM) and maintain tracking of read/write head, peak filters are added to a head tracking servo feedback loop. In some embodiments, several lag-lead type peak filters centered at a plurality of flutter mode frequencies are provided to process a Position Error Signal (PES) read from the read/write head. The several filter are preferably arranged in series (i.e. to operate on the PES sequentially), alternatively the filters can be arranged in parallel. Phase lags and leads caused by the several filters partially cancel at frequencies intermediate center frequencies of the several filters. According to another embodiment two or more, preferably three narrow band filters are used to cover the spectrum of each flutter mode. In a configuration mode, a spectrum of the flutter modes can be obtained and used to set the center frequencies, and bandwidths of filters used to filter out the flutter modes.

Abstract: A disk drive seek control system device to reduce track pitch. When data is recorded, an offset value is added to the position of a read head element along the width of a track corresponding to an offset &Dgr;w between the read head element and a write head element. The value of the offset depends on the yaw angle &thgr; of the head. When data is read, the position of the read head element is chosen to be either the position of the write head element during write operations, or the midpoint between the position of the write head element and the read head element during write operations, or the center of a track.

Abstract: A disk drive seek control system device to reduce track pitch. When data is recorded, an offset value is added to the position of a read head element along the width of a track corresponding to an offset &Dgr;w between the read head element and a write head element. The value of the offset depends on the yaw angle &thgr; of the head. When data is read, the position of the read head element is chosen to be either the position of the write head element during write operations, or the midpoint between the position of the write head element and the read head element during write operations, or the center of a track.

Abstract: A hard disk has a servo loop and a rotating storage medium. The rotating storage medium has one or more significant flutter modes at frequencies below a zero cross frequency of a rejection transfer function of the servo loop. The effect of the forgoing is to allow the servo loop to better track a rotating medium that is subject to significant flutter. Peak filters with frequency bands that substantially overlap frequency bands of the significant flutter modes can also be added to the servo loop to further improve tracking. Multiple narrow band filters with frequency bands overlap can be used to cover the spectrum of a single flutter mode. Two lag-lead filters, the frequency responses of which overlap can be used to cover two adjacent significant flutter modes. At frequencies intermediate to the two adjacent flutter, modes, the lead caused by one filter, will be cancelled by the lag caused by the second.

Abstract: A disk device and a method are described for reassigning data areas (e.g. sectors) which minimize the reduction in the data transfer rate when alternate data areas are used to replace defective areas. The disk device uses a plurality of data zones with spare areas allocated in each data zone. An alternate area is allocated (a) in the spare area within the data zone where the error occurs and (b) at an angular position offset more than a predetermined angle from a position of the data in which the error occurs. The offset angle allows the device time to seek to the alternate area, read the alternate area and seek back to the area following the defective area within a single rotation of the disk.

Abstract: A storage device is described which has a plurality of different error recovery routines which are are divided into groups. When an error occurs, specific routines are selected from the groups in accordance with the error type. The selected routines are executed in order. By preferentially executing the selected routines corresponding to the error type, the error recovery rate in the early stages of the error recovery procedure is enhanced.