Patent application number | Description | Published |
20080239536 | METHOD AND APPARATUS FOR DETECTING DEFECTS OF SERVO DATA IN A DISK DRIVE - According to one embodiment, in a disk drive having a disk medium that has a plurality of sectors, in each of which servo data containing a servo-burst patterns is recorded, a CPU calculates the reliability value of a sector to be evaluated, from a ratio of the sum of the servo-burst values acquired from the sector, to a value obtained by performing low-pass filtering operation on the sum acquired at the time of detection or acquired for the immediately preceding sample. The CPU then determines whether the sector is a defective sector having defective servo-burst patterns, on the basis of the reliability value thus calculated. | 10-02-2008 |
20080291572 | MAGNETIC RECORDING MEDIUM AND METHOD FOR MANUFACTURING THE SAME - According to one embodiment, a magnetic recording medium includes recording areas forming protrusions corresponding to servo signals and recording tracks and includes a crystalline magnetic layer, and non-recording areas comprising an amorphous damaged layer left in bottoms of recesses between the recording areas. | 11-27-2008 |
20090231751 | METHOD AND APPARATUS FOR SERVO CONTROL ASSOCIATED WITH ROTATIONAL SPEED OF DISK IN DISK DRIVE - According to one embodiment, a disk drive is disclosed to which a plurality of disk rotational speed modes can be set. The disk drive is configured such that input of servo data from servo sectors is thinned out by thinning out an output of an interrupt request to a CPU in a high-speed rotation mode. At the time, a disk controller obtains servo data reproduced from all the servo sectors at timing of servo gates and stores it to a register. | 09-17-2009 |
20120273456 | MAGNETIC RECORDING MEDIUM AND METHOD FOR MANUFACTURING THE SAME - According to one embodiment, a magnetic recording medium includes recording areas forming protrusions corresponding to servo signals and recording tracks and includes a crystalline magnetic layer, and non-recording areas comprising an amorphous damaged layer left in bottoms of recesses between the recording areas. | 11-01-2012 |
20120307403 | MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING APPARATUS - According to one embodiment, a magnetic recording medium includes: a data area on which a plurality of first magnetic dots are arranged at predetermined positions to record information; a servo area on which a plurality of second magnetic dots for specifying the positions of said plurality of first magnetic dots are arranged at predetermined positions; and servo frames configured so that a frequency of said servo frames is 2 N per circumference of said medium having a radius, that said servo frames are radially discontinuous, and that said servo frame and a space-area, on which no servo frames exist, are alternately radially arranged at a cycle W. | 12-06-2012 |
20130182350 | MAGNETIC DISK DRIVE AND METHOD FOR SERVO BURST DATA CORRECTION - According to one embodiment, a magnetic disk includes a plurality of tracks each having a plurality of servo frames with servo burst data and repeatable runout correction data written thereto. The repeatable runout correction data includes a pattern repeated at a predetermined period and is written so that beginning of write is delayed by a time corresponding to a correction amount with respect to a base point corresponding to a synchronization timing position in the servo frame. A detector detects a phase delay amount corresponding to a time elapsed until the repeated pattern is read from the servo frame by a magnetic head, with respect to the synchronization timing position. | 07-18-2013 |
20130250452 | DISK STORAGE APPARATUS AND METHOD OF WRITING SERVO PATTERNS - According to one embodiment, a disk storage apparatus includes heads, disks and a controller. The controller performs a servo write control in order to write a plurality of radial servo patterns on each surface of the disk by using the spiral servo patterns. The servo controller positions the head above the spiral servo patterns by using first position information based on the spiral servo patterns. The position information generator generates second position information based on the radial servo patterns read by the head positioned above the spiral servo patterns. The processor corrects target position information for positioning the head based on the second position information by using the spiral servo patterns read by the head. | 09-26-2013 |
20140153127 | DISK STORAGE APPARATUS AND METHOD FOR SERVO CONTROLLING - According to one embodiment, a disk storage apparatus includes an interrupt controller and a servo controller. The interrupt controller determines whether or not to carry out servo interrupt processing and holds a number of negative results of the determination. The servo controller includes an internal model configured to calculate an estimated current position of the head. The servo controller corrects a state of the internal model based on the number of negative results of the determination and performs head positioning control based on a result of a calculation of the internal model, if the result of the determination by the interrupt controller is affirmative. | 06-05-2014 |
20140153131 | DISK STORAGE APPARATUS AND METHOD FOR SERVO CONTROLLING - According to one embodiment, a disk storage apparatus includes a servo system. The servo system includes a state observer and performs a seek operation up to a target position with a current position of a head undetermined. The servo system performs the seek operation based on initial values including a temporary position, while allowing the state observer to operate based on the initial values, until the current position is determined. The servo system determines the current position based on the servo data read from the plurality of servo areas by the read module and a result of estimation by the state observer. | 06-05-2014 |
20140300991 | MAGNETIC DISK APPARATUS AND CONTROL METHOD OF MAGNETIC HEADS - A seek control section is configured so that when a magnetic head is within a prescribed range from a zone boundary when there is a head change request, the magnetic head is driven to seek in a stable region, and then the magnetic head is changed from a current head to a target head. After the change from the current head to the target head, the target head is driven to seek the target position. | 10-09-2014 |