Abstract: In recovering data originally written on a carrier of magnetic media after a catastrophic failure, data may be read without prior knowledge of the write channel by which the data was originally written and in the presence of intersymbol interference of the readback signal. This is accomplished by forming an image of the spatial response function of the magnetoresistive transducer used to recover the data and by forming an image of the raw data read from the carrier of magnetic media by the magnetoresistive transducer for which the response function has been characterized. An image of the distribution of virtual magnetic charge on the carrier of magnetic media is obtained through deconvolution of the image of the response function of the magnetoresistive transducer and the raw readback signal. The readback signal corresponding to the data originally written on the carrier of magnetic media is then recovered by spatial differentiation of the image of virtual magnetic charge.

Abstract: Methods are provided for improving servo-demodulation robustness. Multiple occurrences of a SAM pattern are searched for in a single servo wedge. Each detection of the SAM pattern in the servo wedge is charactered as a good SAM detection or a bad SAM detection. If more than one detection of the SAM pattern in the servo wedge are characterized as good SAM detections, one of the detections is selected as the best good SAM detection. Further servo functions can then be performed based on the best good SAM detection.

Abstract: A disc drive has transducers supported by an actuator to fly proximate data tracks on surfaces of rotating information storage discs. Each of the discs is partitioned into concentric regions. A control system arranges the deposition of data in write operations to the tracks on the disc surfaces, as data is written to the discs, such that the data is sequentially organized both on the tracks and within each of the regions. The control system writes data from a track adjacent a first region boundary in a first direction to a second region boundary until all tracks in a region are full. The control system executes a head switch between adjacent surfaces of the discs. The write sequence is repeated in each adjacent region until all regions are full. The resulting trapezoidal serpentine pattern of actuator movement and head switches is repeated until all of the write operations are complete.

Abstract: In a disk drive system, a data transducer control during a seek operation is based on the distance to be traversed. Acceleration of a motor coupled to the head initiates movement of the head. Deceleration of the motor is initiated based on the distance traversed by the head.

Abstract: In a hard disk drive where data is read from and written to a magnetic disk by a magnetic head in accordance with a command from a host computer, a moving distance of the magnetic head in a radial direction is detected within a predetermined period of time. The magnetic head is moved for seeking by a predetermined distance when the moving distance detected is small. The system and method of the present invention reduces write failures due to the undulation of a lubricant film on the magnetic disk by effectively preventing undulation.

Abstract: There is disclosed a disk drive using a disk medium in which a non-servo range exists. In order to position a head at a target track, a CPU executes a seek operation by normal velocity control using servo data. At this positioning, when the head passes the non-servo range from which no servo data can be obtained, the CPU executes a seek operation by special velocity control to move the head at a velocity calculated based on a moving distance of the non-servo range.

Abstract: An information handling system includes a processor and a disk drive coupled to receive information from the processor. The disk drive is configured to write the information to a first location on a platter. The disk drive is further configured to write the information to n locations on the platter such that a phase difference between successive locations is approximately (360 divided by n) degrees where n is an integer greater than or equal to two.

Abstract: Methods relating to compensating a pre-defined seek profile for use in a data storage device, such as a disc drive, to manage the internal temperature of the device are disclosed. One embodiment disclosed is related to determining a seek profile compensation value that can be used to compensate the pre-defined seek profile for temperature. Another embodiment is a method of using a seek profile compensation value during device operation to maintain the data storage device operating temperature below an operating temperature threshold. Yet another embodiment of the present invention may be thought of as a controller for a data storage device. The controller comprises a microprocessor having a pre-determined seek profile and a means for compensating the pre-determined seek profile based on a current operating temperature.

Abstract: Embodiments of the present invention reduce noise and residual vibration during random access operation of a magnetic disk drive. The magnetic disk drive which executes each instruction from an upper device to move a magnetic head from a start track to an end track on a magnetic disk. In one embodiment, the magnetic disk comprises a processor configured, if a seek span from the start track to the end track, according to a seeking instruction from the upper device, is equal to a preset specific length, to store the seeking instruction for the specific length in memory, and to seek an alternative position from the start track for moving the magnetic head and then seek the end track specified in the stored seeking instruction from the alternative position for moving the magnetic head.

Abstract: A disc drive has transducers supported by an actuator to fly proximate data tracks on surfaces of rotating information storage discs. Each of the discs is partitioned into concentric regions. A control system arranges the deposition of data in write operations to the tracks on the disc surfaces, as data is written to the discs, such that the data is sequentially organized both on the tracks and within each of the regions. The control system writes data from a track adjacent a first region boundary in a first direction to a second region boundary until all tracks in a region are full. The control system executes a head switch between adjacent surfaces of the discs. The write sequence is repeated in each adjacent region until all regions are full. The resulting trapezoidal serpentine pattern of actuator movement and head switches is repeated until all of the write operations are complete.

Abstract: A positioning control apparatus for a magnetic disk apparatus. Internal models and a trajectory generation section are constructed in a control program. Based on generated position trajectory and velocity trajectory and an internal model position and velocity, a model control section outputs a first operation signal Umf for a fixed sample time Tu and then outputs a second operation signal Ums for Tu. The model control section calculates Umf and Ums so as to cause a position Pm and a velocity Vm output by an internal model 2Tu seconds later to coincide with the generated position trajectory and velocity trajectory. When a detector has detected a voice coil saturation current for head movement, a signal obtained by subtracting a position feedback signal Uh from a detected voice coil current is used as an internal model input to thereby cause the model to track a control subject.

Abstract: The present invention comprises an implementation of a variable data TPI hard drive system. In one embodiment, the system is implemented by configuring a group of servo tracks in a radial direction for a hard drive media. The group is comprised of an integral number of servo tracks that is constant throughout the drive device. The number of data tracks in a group is also an integer but will vary for each surface according to the head used for R/W operations for each media surface. Group boundaries coincide with media surface R/W zone boundaries. The groups are accessed in hard drives having multiple surfaces in a serpentine manner. Data tracks per group are reduced from what is achievable to produce desired target capacities.

Abstract: The present invention comprises an implementation of a variable data TPI hard drive system. In one embodiment, the system is implemented by configuring a group of servo tracks in a radial direction for a hard drive media. The group is comprised of an integral number of servo tracks that is constant throughout the drive device. The number of data tracks in a group is also an integer but will vary for each surface according to the head used for R/W operations for each media surface. Group boundaries coincide with media surface R/W zone boundaries. The groups are accessed in hard drives having multiple surfaces in a serpentine manner. Data tracks per group are reduced from what is achievable to produce desired target capacities.

Abstract: An improved system and method for implementing a rotary memory device, including a host system and a disk-shaped memory medium storing position information, or a servo address mark (SAM). If a head fails to read a valid SAM, a dummy SAM is generated to prevent an arm with a read/write head from entering a neutral state. If the normal state cannot be restored within a fixed number of intervals, the system goes into the emergency brake control mode. In this emergency brake control mode, the direction of the head is determined, and the VCM current is applied in such a way drive the arm in the opposite direction. Damage to the magnetic medium and subsequent data loss problems are reduced because the velocity of the head is reduced to a safe level.

Abstract: The position information of the magnetic head is generated also from the data area to improve the positioning accuracy. The magnetic disk drive has a function of oscillating the magnetic head in the radial direction in the data area at a specific frequency and a function of detecting a read signal during the execution of the oscillation function and detects position information of the magnetic head from the detected read signal. The magnetic head position control can be performed in the data area. The magnetic head position signal not dependent on the frequency of a sampling signal generated from the servo information area can be generated. This in turn improves the data recording density and allows a highly precise position control of the magnetic head, thus improving the reliability of the magnetic disk drive.

Abstract: A positioning control method of a magnetic disc apparatus is provided which can permit fast and stable settling to a target position without overshoot or undershoot in connection with a moving distance of one track seek to about 16-track seek for which positioning must be determined within a moving time corresponding to a resonance frequency of a mechanical system. Such a method can also generate a position/velocity orbit for reducing power at a specified frequency, provide acceleration feed-forward compensation which can permit a head to accurately reach the target position even when the feedback system does not function under a condition that external disturbance does not act and generate a position orbit corrected by a controlled object model accurately modeling resonance oscillation up to a moving frequency band are used in combination.

Abstract: In a positioning control apparatus, a distance between an actual position at which absolute values of N and Q head positioning signals whose amplitudes vary cyclically in accordance with a position of a magnetic head and whose phases are different from each other by 90 degrees are equal to each other and an optimum position at which the absolute values of N and Q head positioning signals should be equal to each other is calculated from a deviation of an actual position of the magnetic head with respect to a target value of zero which deviation is obtained when controlling the magnetic head to be positioned at a boundary between ranges in which the N and Q head positioning signals have respective linearities so that the absolute values of N and Q head positioning signals become equal to each other.

Abstract: A magnetic recording disk drive can prevent the deterioration of the head off-track characteristics and the reduction of the drive performance even when an erase band asymmetry resulting from a skew angle exists. A write inhibit slice value for an inner peripheral side offset is made smaller than a write inhibit slice value for an outer peripheral side offset at a position where an erase band on the inner peripheral side is greater than an erase band on the outer peripheral side, so that the adjacent track on the outer peripheral side cannot easily erase a data track. On the contrary, the inner periphery and the outer periphery are paraphrased at a position where the erase band on the outer peripheral side is greater than the erase band on the inner peripheral side.

Abstract: A method and apparatus for reading and writing data from and to a data storage disc in a data storage device. The data storage disc includes a first disc surface and second disc surface for storing data. The data storage device includes an actuator assembly configured to selectively position a first transducer over the first disc surface and a second transducer over the second disc surface, wherein the first transducer is substantially identical to the second transducer. Furthermore, each transducer includes a read element and a write element, wherein the read element is offset from the write element by at least the width of one servo track.

Abstract: An information handling system includes a processor and a disk drive coupled to receive information from the processor. The disk drive is configured to write the information to a first location on a platter. The disk drive is further configured to write the information to n locations on the platter such that a phase difference between successive locations is approximately (360 divided by n) degrees where n is an integer greater than or equal to two.

Abstract: Provided are a method, system, and program for initializing a storage device. A pulse response profile is determined for a storage system in response to a series of signals generated to seek to a location in the storage system. A determination is made of a desired response trajectory for the storage system that optimizes seek performance. An adjustment vector is calculated based on the pulse and step response profiles and the desired response trajectory to optimize the pulse response profile. The adjustment vector is stored in the storage device for use during storage device operations to apply to control signals generated to perform one seek operation.

Abstract: An apparatus is provided for surface-based data mapping for a disk drive system and a method of operation in which adjacent data tracks on the data storage surfaces of a disk drive are grouped into data track sets and data track sets on different data storage surfaces are grouped into bunches. The bunches are used to determine how to perform the logical to physical data layout mapping inside the disk drive. A disk drive controller controls disk read/write heads and provides a data layout mapping that maps logically adjacent data blocks to a data track, then to an adjacent data track radially along the same surface in a data track set in a bunch, and then to a different data track in a different data track set in the bunch.

Abstract: A disk drive device including a plurality of disks that are arranged concentrically about a central axis, wherein each of the disks includes a plurality of concentric tracks of different diameters. Each of the disks also includes a top surface and a bottom surface. There are a plurality of cylinders defined by a combination of one of the tracks from each of the disks, wherein each cylinder consists of a plurality of tracks of a single diameter. A plurality of heads are associated with the disks, wherein each of the heads is configured and arranged to access either a top surface or a bottom surface of one of the disks. The present invention also includes an upper level device for issuing access commands directing the heads to access the disks.

Abstract: A method of tuning a servo control system in a disk drive that implements seeks using a the feed-forward command effort signal uffwd and a PES reference signal r that were designed to be compatible with one another on the basis of a modeled frequency response G0(z) that is different from an actual frequency response G(z).

Abstract: In a recording/reproducing apparatus, the controller has a function of increasing a count of incoming head move request pulses by one each time a head move request pulse is supplied while decreasing the count by one each time the magnetic head is moved over one data track by the magnetic head drive to provide a present count, and control the magnetic head drive to move the magnetic head at a speed based on the present count to a desired data track. Also, the magnetic head can also be moved over successive data tracks to a desired data track with a high accuracy.

Abstract: A mechanism for implementing fault tolerant logic in an information storage system is disclosed. The mechanism comprises an inhibit logic which is invoked when the first RUNOUT block of a link sequence is detected. Once invoked, the inhibit logic outputs a disable signal, and so long as the disable signal is asserted, certain control signals are inhibited. These control signals may include a trigger signal, a target match signal, and a miss signal. The disable signal is maintained during the reading of blocks, such as link sequence blocks, in which information corruption is most likely to occur. By doing so, the inhibit logic prevents erroneous signals generated as a result of corrupted information from adversely affecting the operation of the storage system. As a result, the corrupted information is tolerated.

Abstract: A servo system and method position a head laterally with respect to magnetic tape longitudinal defined servo bands arranged in a longitudinally shifted pattern for identification, and separated by data tracks. A servo controller responds to a loss of lateral position, sensing an estimated longitudinal position of the magnetic tape. If the estimated longitudinal position is within a predetermined distance of an end of the tape, the servo controller operates a drive to continuously move the tape away from the sensed end. The servo controller senses a home lateral position sensor to determine whether a compound actuator is within a predetermined distance of the edge of the magnetic tape. If so, it operates the coarse actuator portion of the compound actuator to move laterally away from the edge of the magnetic tape; else, to move toward the edge.

Abstract: In an FDD control apparatus for controlling a floppy disk drive for driving a floppy disk loaded in the floppy disk drive, a counter (34) produces a target track position signal indicative of a target track position for magnetic heads in response to an external seek direction signal and an external step signal. A counter (35) is activated when the floppy disk is loaded in the floppy disk drive to generate an internal step signal. When the floppy disk is loaded in the floppy disk drive, a counter (33) is put into an active state to produce a current track position signal indicative of an actual current track position for the magnetic heads in response to a selected seek direction signal and a selected step signal. A comparing circuit (36) compares the target track position signal with the current track position signal to produce a coincidence signal and an internal seek signal.

Abstract: In a hard disk drive where data is read from and written to a magnetic disk by a magnetic head in accordance with a command from a host computer, a moving distance of the magnetic head in a radial direction is detected within a predetermined period of time. The magnetic head is moved for seeking by a predetermined distance when the moving distance detected is small. The system and method of the present invention reduces write failures due to the undulation of a lubricant film on the magnetic disk by effectively preventing undulation.

Abstract: A servo control method and an information storage device are provided. In the method and device, positional information is detected in accordance with servo information including a plurality of positional regions having phase differences between tracks. The positional regions consist of a first positional region in which the phase difference between tracks is +90°, a second positional region in which the phase difference between tracks is −90°, a third positional region in which the phase difference between tracks is +90°, and a fourth positional region in which the phase difference between tracks is −135°. A deviation from a reference track is detected from the phase difference between the vector of a reproduction signal of the second positional region and the vector of a reproduction signal of the fourth positional region. Thus, a wide range of deviation can be detected.

Abstract: Methods and apparatus for processing a seek request on a disk drive apparatus having a disk drive head is disclosed. The seek request is processed. During the seek request, the disk drive head is traversed across an actual distance. At least one expected seek time associated with the actual distance is obtained from a set of seek time data. One or more measurements are performed on the disk drive apparatus to obtain an update value. At least one expected seek time is then updated such that at least part of the update value is included in the at least one expected seek time.

Abstract: The present invention is directed to utilizing the capabilities of multi-stage actuators in disk drives to write servo tracks that have a variable number of tracks-per-inch (TPI) from head to head, thereby improving both the performance of the drive and manufacturing yields. An appropriate TPI for a particular head has been found to depend on a number of factors that vary from head to head. Consequently, the initial step is to determine an appropriate TPI for at least one of the heads or, more preferably, all of the heads in the drive. The determination typically involves measurements such as read and write width measurements and off-track performance tests for the relevant heads. Once an appropriate TPI format has been determined, the servo tracks are written according to the TPI formats using either a servo track writer or self servo track writing.

Abstract: A disk drive and a disk drive control method is described which reduces the number of one track seeks a drive performs. The one track seeks can operate the actuator bearing in a non-linear mode or can increase in the friction of the actuator bearing which leads to servo positioning inaccuracies. In the disk drive the logical block address (LBA) assignments are made so that when sequential addresses are allocated to two different tracks, the tracks are physically non-adjacent. Thus, when a sequential LBAs are read across a track boundary, the actuator is moved farther than would be required if the LBAs were assigned the adjacent tracks.

Abstract: Methods and systems in a data storage device selectively employ a seek time array and/or a seek time list to accurately predict a time required for a seek operation to move a transducer in the data storage device a given seek distance. The seek time list and/or seek time profiles are automatically compiled in the data storage device based on seek time entries located in a servo data table located in the data storage device.

Abstract: A data zone optimization method and architecture for optimizing the location of the data zone on a data storage disk is disclosed. The data zone is preferably biased toward the outer diameter of the disk, and is referenced to a data zone starting location established proximate a load/unload ramp apparatus. An optimum starting location for the data zone of an initially unformatted data storage disk is preferably determined by contacting the load/unload ramp with the transducer assembly, disengaging the transducer assembly from the ramp, and writing servo information indicative of the data zone starting location at a disk location proximate the ramp and transducer assembly contact point. Servo information indicative of the data zone is written at inner diameter disk location with respect to the optimum data zone starting location. The optimized data zone architecture may have a predetermined or variable data storage capacity.

Abstract: The position information of the magnetic head is generated also from the data area to improve the positioning accuracy. The magnetic disk drive has a function of oscillating the magnetic head in the radial direction in the data area at a specific frequency and a function of detecting a read signal during the execution of the oscillation function and detects position information of the magnetic head from the detected read signal. The magnetic head position control can be performed in the data area. The magnetic head position signal not dependent on the frequency of a sampling signal generated from the servo information area can be generated. This in turn improves the data recording density and allows a highly precise position control of the magnetic head, thus improving the reliability of the magnetic disk drive.

Abstract: A method and system for reducing positioning noise in a data storage system are provided. An access device is positioned over a data storage medium using a stream of bursts stored on the medium. The bursts are sensed at a frequency determined by the rate at which the medium is moved relative to a sensing device. Output positioning values are provided to position the access device at a frequency higher than the frequency at which the positioning bursts are sensed, and/or at random times. The random times may be calculated as random advances or delays from time points occurring at a fixed frequency.

Abstract: A head actuator includes a head slider for carrying a head for recording information to or reproducing information from a recording medium; and a head supporting member for supporting the head slider. The head supporting member includes a substrate and a driving element provided on at least one surface of the substrate for generating an expanding and contracting force in a longitudinal direction in accordance with an external signal, wherein the external signal is applied to the driving element so as to expand or contract the head supporting member in the longitudinal direction and to position the head in a radial direction of the recording medium. The head supporting member includes a first area on which the head slider is provided, a second area on which the driving element is provided, and a third area for connecting the first area and the second area. The driving element has a geometrically central face.

Abstract: An improved system and method for implementing a rotary memory device, including a host system and a disk-shaped memory medium storing position information, or a servo address mark (SAM). If a head fails to read a valid SAM, a dummy SAM is generated to prevent an arm with a read/write head from entering a neutral state. If the normal state cannot be restored within a fixed number of intervals, the system goes into the emergency brake control mode. In this emergency brake control mode, the direction of the head is determined, and the VCM current is applied in such a way drive the arm in the opposite direction. Damage to the magnetic medium and subsequent data loss problems are reduced because the velocity of the head is reduced to a safe level.

Abstract: A method and apparatus for reading and writing data from and to a data storage disc in a data storage device. The data storage disc includes a first disc surface and second disc surface for storing data. The data storage device includes an actuator assembly configured to selectively position a first transducer over the first disc surface and a second transducer over the second disc surface, wherein the first transducer is substantially identical to the second transducer. Furthermore, each transducer includes a read element and a write element, wherein the read element is offset from the write element by at least the width of one servo track.

Abstract: A disc-shaped recording medium for magnetically recording information signals, in which logical block addresses are associated with the recording tracks on the disc in such a sequence in which the logical block addresses proceed in a recordable information area towards the outer rim side, with a first recording track at a mid portion between the innermost recording track and the outermost recording track on the lower disc surface as a logical starting point, until reaching a second recording track, the logical block addresses then proceeding from a third recording track at a mid portion between the innermost recording track and the outermost recording track on the upper disc surface towards the inner rim side as far as a fourth recording track, the logical block addresses then proceeding towards the outer rim side from the next recording track of the second recording track on the lower disc surface lying towards the outer rim side, as far as the outermost recording track on the lower disc surface, the logical