Abstract: Provided are a tape drive, tape drive controller, and method for measuring amplitudes of written tracks to determine errors in read and write elements. The write element writes a data pattern and erase pattern to the tape medium to provide the data pattern and the erase pattern on sides of the data pattern. The read element is positioned to measure amplitudes at offsets in the data pattern. The offsets and the amplitudes at the offsets are processed to estimate a maximum amplitude read while the read element is estimated to be positioned entirely in the data pattern and estimate an offset at which the read element reads a fixed percentage of the maximum amplitude. A width of the read element is estimated based on the estimated offset. The estimated width of the read element is outputted to determine whether the estimated width of the read element is acceptable.

Abstract: The present disclosure provides a data write-in method and apparatus. The method includes: generating, by a first storage module, a dataset to be written into a second storage module, where first data in the dataset is sorted according to destination storage addresses of the first data; and sequentially sending, by the first storage module, the first data in the dataset to the second storage module. The embodiments of the present disclosure may increase the speed at which the first storage module writes data into the second storage module.

Abstract: According to one embodiment, a magnetic disk device includes a disk, a head including a first write head and a second write head configured to write data to the disk and a read head configured to read data from the disk, and a controller configured to write write data to a first area of the disk with the first write head and to overwrite the write data written with the first write head in the first area with the second write head.

Abstract: Exemplary methods, apparatuses, and systems include a memory controller receiving a first physical address corresponding to a logical address and data and initiating storage of the data at the first physical address. The memory controller sends a message indicating that the data has been successfully stored at the first physical address before determining if the data was successfully stored at the first physical address. Upon determining that the data failed to store at the first physical address, the memory controller retrieves the data from a volatile memory associated with the first physical address. The memory controller sends a request and receives a second physical address for the retrieved data. The memory controller initiates storage of the data at the second physical address.

Abstract: According to one embodiment, a magnetic disk device includes a disk that includes a plurality of tracks, each track including a plurality of sectors for storing data, a head that is for writing data to the plurality of sectors and reading data from the plurality of sectors, and a controller. The controller is configured to determine that a first sector of the plurality of sectors is not able to be read and is a defective sector, determine that a second sector of the plurality of sectors is disposed along a line that extends through the first sector and a defective sector included in a first list of defective sectors, register the second sector in the first list of defective sectors, and reallocate an address corresponding to the second sector to a first alternative sector included on the disk.

Abstract: A two-dimensional absolute encoder includes a scale having marks arranged thereon along first and second directions different from each other, a detector configured to perform first detection that detects rows of a first number of marks arranged in the first direction and second detection that detects rows of a second number of marks arranged in the second direction, and a processor configured to determine absolute positions of the scale in the first and second directions based on outputs from the detector. Each of the marks has one of different characteristic values each corresponding to a combination of a quantized first code for indicating a position in the first direction and a quantized second code for indicating a position in the second direction, the number of the different characteristic values being smaller than the number of the combinations.

Abstract: According to one embodiment, at demodulation of an A-phase burst pattern and a B-phase burst pattern arranged in a down-track direction so as to be different from each other in phase in a cross-track direction, the demodulated position of a magnetic head is calculated based on a sin component and a cos component in the A-phase burst pattern and a sin component and a cos component in the B-phase burst pattern.

Abstract: An adaptive guard band scheme is disclosed for a data storage device. In illustrated embodiments, the adaptive guard band scheme formats different guard band cylinders and track zeros for different heads depending upon a contact cylinder of the different heads. In an illustrative embodiment, the adaptive guard band scheme utilizes the contact cylinders for the heads and a no fly cylinder to determine track zero(s) and extended data zone(s) for select heads.

Abstract: 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.

Abstract: It is determined whether one or more heads of a data storage device (DSD) have been within a radial position of one or more disks of the DSD for more than a threshold period of time. When it is determined that the one or more heads have been within a radial position of the one or more disks for more than the threshold period of time, the one or more heads are radially moved by more than a predetermined distance to reduce a development of variations in a distribution of lubricant on a first surface of the one or more disks.

Abstract: The disclosure is related to systems and methods for adaptive seek latency in a rotating storage device. In one example, a servo control circuit can be configured to determine a seek latency and provide the seek latency to another controller or control circuit that is configured to implement the seek latency. Further, the servo control circuit can calculate the seek latency based on a measurement of a variable condition of a device and the servo controller can adjust the seek latency as the condition varies. In some examples, the variable condition may include power measurements, temperature measurements, a fault rate, other conditions, or any combination thereof. Also, different algorithms for calculating the seek latency may be implemented based on a selected goal of the system, such as power savings or reduced head vibration.

Abstract: A hybrid drive is disclosed comprising a head actuated over a disk, and a non-volatile semiconductor memory (NVSM) operable to cache data. When beginning to spin up the hybrid drive, a first spin-up profile is used while servicing access commands using the NVSM, including write commands and read commands. When a cache event occurs, spinning up the disk is finished using a second spin-up profile in order to spin-up the disk faster.

Abstract: A disk drive is disclosed comprising a head actuated over a disk including a plurality of contiguous servo tracks for defining a plurality of data tracks. A first write command comprising first write data is received, and a first density of first data tracks over a first plurality of the contiguous servo tracks is selected, wherein the first write data is written to the first data tracks. A second write command comprising second write data is received, and a second density of second data tracks over the first plurality of the contiguous servo tracks is selected, wherein the second density is different than the first density. The second write data is written to the second data tracks.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of physical zones including a first physical zone and a second physical zone, wherein the first physical zone comprises data tracks recorded at a first data rate and the second physical zone comprises data tracks recorded at a second data rate different than the first data rate. A write command is received including data and at least one logical block address (LBA). One of the first and second physical zones is selected based on a power parameter affecting a power consumption of the disk drive, and the data is written to a data sector in the selected physical zone. A physical block address (PBA) is assigned to the data sector, and an LBA to PBA map is updated for the written data.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of data tracks, wherein the head comprises a write element and a read element. An asperity in a target data track is detected, and a range of data tracks proximate the target data track is mapped out, wherein the range of data tracks spans at least twice a radial offset between the read element and the write element at the radial location of the target data track.

Abstract: A disk drive. The disk drive includes a head, a motion mechanism, and a controller. The head is configured to access a disk configured to store data. The motion mechanism is configured to move the head. The controller is configured to determine a seek direction when an error occurred; and, the controller is configured to repeat a seek as a repeat seek to a target radial position from a direction opposite to the seek direction in an error-recovery process for the error which occurred in the seek in which the head moved to the target radial position.

Abstract: A hard-disk drive. The hard-disk drive includes a magnetic-recording disk in which tracks adjacent to each other are magnetically separated, a spindle motor which drives the magnetic-recording disk, a magnetic-recording head equipped with write element and read element, an actuator for positioning the magnetic-recording head on a predetermined track on the magnetic-recording disk, and a control unit. The control unit is configured to store information about an over-write-only track that is provided for a plurality of tracks including n consecutive tracks in at least a partial radial area of the magnetic-recording disk and an offset amount. In a radial area of the magnetic disk where the over-write-only track is located, the control unit is configured to record with an offset by an offset amount from a center of a track toward the over-write-only track with respect to n?1 tracks of the plurality of n tracks, excluding the over-write-only track.

Abstract: A method of self servo-writing servo information to a plurality of disk surfaces in a disk drive that includes writing servo information to a plurality of disk surfaces in a first direction, writing servo information to a plurality of disk surfaces in a second direction, and determining an amount of overlap to be written on a reference surface with the reference head that will produce an overlap of servo information on each of the surfaces in the disk drive to which servo information is to be written. The method also includes switching to different tables when seeking across the overlap or border areas.

Abstract: A hard disk drive system that includes one or more rotating data storage platters, a drive controller and multiple actuator assemblies and corresponding respective read/write heads. The actuator assemblies are separately moveable for performing separate data seeks. The controller is configured to interleave the seek and read/write operations of the multiple actuator assemblies and read/write heads with one another.

Abstract: Embodiments of the present invention help to increase the capacity and the reliability of a disk drive device to improve the manufacturing yield thereof. An embodiment of the present invention sets a data track pitch for each head slider (recording surface) in accordance with head characteristics. This method for specifying the data track pitch is based on the distance between erase band ends (EBEs) of the both adjacent data tracks. The erase band of a data track is a band defined as the area where the already written data are erased in writing the data track. The distance between the erase band ends of the both adjacent data tracks corresponds to the width SW of the area which is not erased by the adjacent data tracks. Specifying the data track pitch based on this leads to increase in the data capacity of each recording surface and secure prevention of occurrence of a squeeze error.

Abstract: A storage device receives and holds a storage medium that is subjected to first servo writing processing for writing servo information, a Gray code of which is offset, from an inner cylinder or an outer cylinder to a predetermined cylinder and, after the first servo writing processing, subjected to second servo writing processing for writing servo information from an opposite direction to the predetermined cylinder and in which Gray codes are written to be offset not to overlap in the first or second servo writing processing and the pieces of servo information having different mark patterns are written in the first servo writing processing and the second servo writing processing. The storage device acquires cylinder information and mark patterns from the servo information written in the held storage medium and controls a position of a head based on the acquired cylinder information and mark patterns.

Abstract: Methods and structure for switching heads on a multiple recording surface disk drive that uses bi-directional radial writing toward a zipper zone at a middle diameter. When switching from a first head to a second head, features and aspects hereof assure that the second head will not be positioned in the zipper zone of the corresponding second surface and hence will not lose track following servo synchronization and control. In one aspect, added buffer or guard tracks having valid servo information but no data are added on either side of the zipper zone to assure that under the worst-case misalignment of surfaces the second head will not be positioned in its corresponding zipper zone when switching from the first head.

Abstract: Provided is an apparatus for adjusting static attitude of a thin film magnetic head attached to a flexure of a head arm assembly. The apparatus has an adjusting unit for bending the flexure, a laser emitter unit for irradiating a laser beam to a bent area of the flexure a measuring unit for measuring a static attitude angle of the thin film magnetic head, and a computer system including a CPU and a memory unit in which adjustment conditions corresponding to static attitude angles of the thin film magnetic head are previously ranked and memorized. The CPU is configured to retrieve from the memory unit a particular adjustment condition corresponding to a measured angle supplied from the measuring unit and supply the retrieved adjustment condition to the adjusting unit, enabling the adjusting unit to bend the flexure based on the retrieved adjustment condition supplied from the computer system.

Abstract: One embodiment of a tape drive apparatus has a non-volatile memory for storing an identifier. Data that is written by the tape drive apparatus to a loaded tape media is tagged using the identifier. This facilitates to identify the tape drive apparatus that has written the data onto the tape media such as for the purpose of failure analysis. Other devices and methods are included.

Abstract: Methods and structures for writing thermal lead-in sequences to provide head stability in a dynamically mapped storage device. In a dynamically mapped storage device in which all user supplied logical blocks are dynamically mapped by the storage device controller to physical disk blocks, features and aspects hereof provide writing thermal lead-in sequences to allow the write head to stabilize. As the write head begins writing a sequence of data to the recordable media, the write head may not have a desired thermal stability. Thus, there may be thermal flux with some of the data, affecting the reliability of the data. Mapping features and aspects hereof allow the write head to write a thermal lead-in sequence of data that does not destroy valuable data, allowing the write head to begin writing before stabilizing. Writing the thermal lead-in sequence will cause the write head to warm up and become stable, and thus be ready to write valid data.

Abstract: A bidirectional disc sweep routine accelerates the transducer in a storage device from a first predefined radius toward the inner radius to a second predefined radius, and accelerates the transducer from a third predefined radius toward the outer radius to a fourth predefined radius.

Abstract: To reduce power consumption of an information storage device, a control circuit for the information storage device stops the supply of a formatter clock or an ECC unit clock simultaneously with a seek operation. When a clock stop time has elapsed by the time obtained by subtracting at least a time required for restarting the formatter or the ECC unit from a seek time, the control circuit restarts the supply of the formatter clock or the ECC unit clock.

Abstract: Methods of controlling seeking of a transducer that is adjacent to a rotatable disk in a disk drive include determining an expected seek time associated with moving the transducer from an initial track to a target track on the disk. An expected rotational latency time is determined which is associated with rotating the disk to move an addressed data block on the target track adjacent to the transducer after the transducer would be expected to arrive at the target track. A scaled velocity limit is determined which is based on the expected seek time and the expected rotational latency time. While seeking the transducer from the initial track to the target track, the radial velocity of the transducer relative to the disk is regulated in response to the scaled velocity limit. Related apparatus for controlling seeking of a transducer are also described.

Abstract: There is provided with command execution method, including; detecting a use situation of a non-volatile memory; selecting, when the use situation is low, the command which enables the disk head to be located at a start position of writing or reading most rapidly from among the write commands and the read commands assuming that the disk head performs the fast seek for the write command and the slow seek for the read command; selecting, when the use situation of the non-volatile memory is high, the command which enables the disk head to be located at the start position of writing or reading most rapidly from among the write commands and the read commands assuming that the disk head performs the slow seek.

Abstract: A disk drive is disclosed which receives a plurality of access commands from a host, where each access command identifies a target track. The access commands are stored in a command queue, and for each command in the command queue, a seek length is computed corresponding to a number of tracks between a current track the head is over and the target track of the access command. A seek time is computed in response to the seek length using a seek profile comprising a first plurality of seek length segments and a variance group comprising a second plurality of seek length segments. Each seek length segment corresponds to a range of seek lengths, and the first plurality of seek length segments is different than the second plurality of seek length segments.

Abstract: A magnetic recording disk drive has disks with identical pre-patterned servo patterns on their front and back surfaces and a servo control system for positioning the read/write heads using the servo signals from the identical servo patterns. The servo sectors on the two disk surfaces form identical patterns of angularly spaced arcuate-shaped lines that extend generally radially across the data tracks. The arcuate-shaped lines on one surface, the front surface, generally replicate the path of the recording head as it is moved across the data tracks by a rotary actuator, so that there is a constant sampling rate of the servo sectors on the front surface regardless of radial position of the head. However, the arcuate-shaped lines on the other surface, the back surface, do not replicate the path of the recording head so the servo sampling rate is not constant but varies with radial position of the head.

Abstract: Embodiments of the invention prevent a magnetic head from coming into contact with a protrusion on a magnetic disk. In one embodiment, a head gimbal assembly includes a piezoelectric actuator for changing the flying height of a head/slider assembly. The address of a protrusion on a magnetic disk is preregistered in a nonvolatile memory. When a seek operation or following operation is to be performed, the head/slider assembly flies at a reference flying height. Before the protrusion passes below the head/slider assembly, an operating voltage is applied to the piezoelectric actuator to increase the flying height. After the protrusion passes below the head/slider assembly, the head/slider assembly flies at the reference flying height with operating voltage application stopped.

Abstract: A method and apparatus to perform write reordering. The method includes extracting a seek time table containing seek times corresponding to a desired seek speed among different seek times to a surface of a disk, and reordering an order to write a data in a plurality of writing positions on the surface of the disk by use of the seek time table extracted. A performance of a hard disk drive optimizes the write reordering under a current condition.

Abstract: The present invention relates to a hard disk drive performing a seek control method using a multi-sinusoidal wave acceleration profile, where the seek control method is capable of coping with a variation in a voice coil motor driving current due to variances in a peripheral environment. The seek control method of the present invention includes: calculating a seek time scaling (STC) related to variations in a voice coil motor (VCM) driving current due to variation in a peripheral environment; calculating an acceleration distance ratio (ALR) of an acceleration distance to a maximum seek distance without a coast mode according to the STC; calculating position profiles in an acceleration mode, the coast mode and a deceleration mode, respectively, using both the STC and the ALR; and performing a seek operation by generating the VCM driving current according to the position profiles and applying the VCM driving current to a VCM.

Abstract: When an idle seek operation of a magnetic disk drive is executed under a velocity control utilizing a back electromotive force of a VCM actuator, the accuracy of the velocity control is deteriorated due to temperature variation of the VCM. To eliminate this disadvantage, a calibration of the velocity control is executed by using control information, such as a track number read from the magnetic disk medium. After the velocity control has been executed for an appointed period, by detecting the back electromotive force from the VCM actuator, an MR sense current and a power of a read write LSI are turned on for a time, positioning information on the magnetic disk medium is read out, parameters to be used for the velocity control are calibrated, and thus a stability of the control can be obtained.

Abstract: A method of reducing read/write head wear and disc wear through controlling fly height of the read/write head to improve reliability of a disc drive is disclosed. Absent data transfer operations, a fly height adjusted sweep cycle routine executes a sweep cycle sub-routine that positions the read/write head at an inner most data track, lowers the fly height of the read/write head and performs a seek to the outer most data track to sweep debris from a recording surface and then raises the fly height above an operating fly height for the read/write head, oscillates the read/write head to dislodge debris accumulated on the read/write head and holds the read/write head at the raised fly height while awaiting a new data transfer operation.

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 motion pattern of an actuator supporting a head is monitored during/after a disc spin-up. The monitor's signal is configured to generate a digital indication of where the head was just before the spin-up. The digital indication is optionally a single-bit indicator that is used directly as a decision of whether to continue a start-up operation.

Abstract: The present invention provides a measurement apparatus for obtaining a suitable position on a suspension where a more miniature magnetic head slider is to be mounted to the suspension, the apparatus including a front camera having a photographing optical axis within a plane parallel to a plane of extension of a suspension and directed to the suspension, and a side camera having a photographing optical axis within the parallel plane and which is different from that of the front camera. Coordinates of a top portion of a convex surface of a dimple formed in the suspension are obtained with these cameras. The resultant coordinates and coordinates of the deepest portion of a recess surface of the dimple are correlated with each other, whereby in actual mounting of the magnetic head slider, the deepest portion of the recess surface of the dimple which is readily recognized is measured.

Abstract: An access performance adjusting method is adapted to a storage apparatus having a storage to prestore a skew quantity that is used to shift a data write starting position of each track of a recording medium depending on a head moving time required to move a head from one track to another track during a sequential access in which a plurality of tracks of the recording medium are accessed sequentially. The method includes measuring an apparatus performance with respect to a combination of the head and the recording medium, calculating a skew adjusting quantity with respect to the combination based on a reference apparatus performance and the measured apparatus performance, and adjusting the skew quantity read from the storage by the skew adjusting quantity and storing the adjusted skew quantity in the storage as an updated value of the skew quantity.

Abstract: A disk drive is disclosed comprising a disk having a plurality of servo sectors defining a plurality of servo tracks, wherein each servo sector comprises a track address identifying a corresponding servo track. A head is actuated over the disk, and a ramp is positioned near an outer diameter of the disk, wherein an edge of the ramp extends over a plurality of the servo tracks. The head is loaded from the ramp onto the disk, and a track address in at least one of the servo sectors is detected and stored. The process is repeated a number of times, and then a starting track proximate an outer diameter of the disk is identified in response to the detected and stored track addresses.

Abstract: Method and apparatus for control object manipulation from an initial position to a final position. A jerk control profile describes a near time-optimal jerk trajectory for the control object and includes a sequence of first, second and third sinusoidal pulses of respectively alternating polarity and common absolute magnitude. The area of the second pulse is nominally equal to the combined area of the first and third pulses, and the pulses are preferably symmetric about the respective maximum pulse values. Associated control profiles (control voltage, current, velocity, displacement, etc.) are derived from the jerk control profile. For longer seeks, constant, non-zero jerk segments are inserted into the profile between the pulses, during which control voltage is maintained near saturation. The control object preferably comprises a transducer in a data storage device and the jerk control profile is stored in a memory location of the device.

Abstract: A method and apparatus for controlling a track seek servo of a disk drive. The method of controlling the track seek servo of the disk drive having a transducer and a disk with a plurality of tracks, includes moving a transducer to a space over a target track of the plurality of tracks according to a track seek controlling process in which an asymmetrical sine wave acceleration trajectory a(t) is used in a track seek mode.

Abstract: The burst pattern shape in a discrete medium is set to a shape (truncated quadrangular pyramid shape) having substantially trapezoidal shapes in a track width direction and in a track circumferential direction, respectively, and a predetermined relationship is satisfied among W1, W2, Tp, and Wr where W1 represents an upper side corresponding to the surface of a convex magnetic recording layer and W2 a lower side corresponding to the lower surface of the convex magnetic recording layer in the trapezoidal shape in the track width direction, Tp represents a data track pitch of a data information recording portion, and Wr represents a read width of a magnetic head. Therefore, the burst pattern shape makes it possible to largely reduce a production load in processing and still to obtain an accurate position error signal.

Abstract: Track pitch for writing tracks on a disk is determined based on an available stroke across the disk. The available stroke is identified by searching across the disk for where information can be written and read. The track pitch is determined for writing tracks on the disk based on the available stroke across the disk. Tracks are written on the disk based on the determined track pitch.

Abstract: A method and apparatus for overwriting data in a disk drive is provided. In one embodiment, a disk drive includes a disk surface and a write head associated therewith. The disk surface has servo information and user data written thereon. The user data is written by the write head. User data is overwritten by sweeping the write head from a first radius on the disk surface to a second radius on the disk surface, while the write head is actively writing.

Abstract: A method of representing a serpentine track accessing format includes obtaining a plurality of head and physical track number pairs in the serpentine track accessing format. Then, each of the head and physical track number pairs are mapped to a unique virtual track number. In some embodiments, the unique the virtual track numbers are in a non-continuous monotonic order. In some embodiments, the unique virtual track numbers are assigned based upon a modulo M which is a function of a maximum number of tracks per physical zone. Translation engines which perform the mapping, as well as data storage systems which include the translation engines, are also disclosed.

Abstract: In a disk device having a ramp-load mechanism, stable retry operation is performed even upon occurrence of seek errors. A disk device is provided with a ramp to which the head is retracted from the disk, at the time of seek error retry, prior to beginning seek retry, checks whether the head has climbed onto the ramp. And if the head has not climbed onto the ramp, normal seek retry is performed, but if the head has climbed onto the ramp, unloading is first performed before seek retry. Consequently crashes due to climbing onto the ramp due to a seek error in a ramp-load device can be prevented, and improvement of device reliability can be expected.

Abstract: A disk drive is disclosed comprising a disk, a head, and a voice coil motor (VCM) for actuating the head over the disk. The disk drive executes a rotational position optimization (RPO) algorithm to select a next command to execute relative to an estimated seek time computed for each command in a command queue. A seek time parameter is estimated and a seek time delta computed in response to the estimated seek time parameter. The seek time delta is added to a nominal estimated seek time to generate a modified estimated seek time for each command in the command queue, thereby optimizing the RPO algorithm.

Abstract: In an apparatus for recording and reproducing a burst-like digital information signal, a method capable of predicting the time of occurrence of a header indicating the head of the first data of a digital information signal during its reproduction from a recording medium. The digital signal includes a plurality of data blocks each including a header indicative of the head of the block, and each header includes the address of the block. During recording of the digital signal on the recording medium, a plurality of headers which are substantially the same as the headers of the data blocks and including addresses having given relations with the addresses of the data blocks are inserted in a clock regenerating signal recorded before the digital signal for regenerating the clocks for the signal. The headers are inserted at a period equal to the length of each data block so as to be synchronized with the headers of the data blocks.