Abstract: A method of storing data on a surface of a storage disk, the data being capable of verifying an identity of the surface, includes determining first check data from first alignment correction data associated with a first storage surface. The method also includes determining second check data from second alignment correction data associated with a second storage surface such that the second check data is different from the first check data if the first and second alignment correction data are identical. The method further includes writing the first and second check data to the first and second storage surfaces in association with the first and second alignment correction data, respectively.

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 method and apparatus for identifying a track (42) of a rotating disk (12) of a mass data storage device (10) uses EPR4 data detection techniques. The values of the encoded track identification indicia are selected so that they have a distance between any two track identification codewords that is larger than the minimum distance of the codeset from which they were selected. The identification indicia (110-113) are read from the disk (12) using a read head (18), and processed using EPR4 data equalization techniques in an EPR4 Viterbi detector (92). The Viterbi detector (92) may have a trellis in which data paths of minimum distance of the codeset from which the track identification indicia (110-113) were selected do not exist. The Viterbi detector (92) may be used also to detect data pulses (64) by switching its mode of operation from a track identification mode to a data detection mode.

Abstract: A transducer position sensing system in a disc drive to take frequent data measurements from micro-servo sectors on the disc and to interpret the information to predict recording failures. The disc drive is formatted with many small or micro-servo sectors containing, among other things, a servo address mark, encoded disc location information, and radial track position information. The sensing system frequently retrieves this information through the transducer, compares the measurements to expected values, and given unexpected measurements predicts errors. The time elapsed between the passing of servo address marks can be used to predict adjacent sector overwrites. The radial track position information can be used to predict off-track write errors. The radial track position signal amplitude can be used to predict the transducer moving too far from the disc, resulting in skip write errors.

Abstract: A magnetic disk recording and reproducing apparatus comprising a unit for inserting an error correcting code related to control information into said control information on data; a recording control unit for recording in a plurality of sectors formed by dividing the recording area of a magnetic disk, each sector having an ID area for recording said control information and a data area, provided adjacent to and behind said ID area, for recording said data; and a error correcting unit for correcting said control information of said ID area by said error correcting code before data is read from said data area corresponding to said ID area or data is recorded in said data area corresponding to said ID area.

Abstract: A magnetic disk tester has a head clamp (35, 218) to position a magnetic head (15, 289). The head clamp has a micromotion stage (55, 273) provided with a stage (59, 205) which is horizontally moved by a piezo-element (77). The magnetic head is attached to the piezo-stage (55, 273).

Abstract: A disc drive includes a base and a disc rotatably attached to the base. The disc drive also includes an actuator assembly rotatably attached to said base and a device for moving the actuator assembly. The disc drive includes servo circuitry and a controller for controlling movement of the actuator and head switches during track seek operations. The disc drive determines the average seek time for each head and also measures the amount of time for a head switch from the transducer head having the shortest average seek time to all the other transducing heads in the disc drive. When a seek is performed, the controller in the disc drive determines if the shortest average seek time plus the seek time from the transducing head to the transducing head on the surface containing the target track and sector is less than the average seek time of the head on the surface having the target track and sector.

Abstract: A method, apparatus, and article of manufacture for controlling a disk drive with multiple VCMs is disclosed. The apparatus comprises a first disk storage surface and a second disk storage surface. The first disk storage surface has a plurality of first data segments and a plurality of first servo track segments interspersed therebetween, and is readable and writeable by a first head controllable according to a first servo track signal read from at least one of the first servo track segments. The second disk storage surface has a plurality of second data segments and a plurality of second servo track segments interspersed therebetween, and is readable and writeable a second head separately controllable from the first head according to a second servo track signal read from at least one of the plurality of second servo track segments.

Abstract: The present invention provides a digital filter which is capable of preventing filter outputs from being discontinuous when a filter characteristic is changed. Initially, a servo assistant (SA) computes parameters for computing servo data, and based on the computed parameters, the SA judges an operating mode. If the mode has been changed, the SA will advance in processing. Next, the parameters of a filter are changed in correspondence with the judged operating mode, and the initial values of the interior variables of the filter are set to appropriate values.

Abstract: A method for constructing and linearizing a position error signal (PES) derived from primary and quadrature servo burst pairs in an embedded servo disk drive. The construction method mathematically provides predetermined transition values at the commutation positions connecting adjacent PES segments so that the overall, indicated position signal is numerically continuous from segment to segment. The linearization method compensates for nonlinearity in the PES segments, and thereby in the indicated position signal, without affecting the predetermined transition values at all, or by modifying the predetermined transition values while maintaining continuity.

Abstract: Steps for isolating and correcting total written-in repeatable run-out error written into servo sectors of a disc drive include, determining a total repeatable run-out error value for each servo sector, isolating a repeatable error value component of the total written-in repeatable run-out error value for each servo sector, removing the repeatable error value component from total written-in repeatable run-out error value to provide a non-repeatable error value component of the total written-in repeatable run-out error value for each servo sector, providing both the repeatable and non-repeatable error value components to a processor for generation of compensation signals, and applying the compensation signals into a servo control circuit of control loop of the disc drive using compensation circuits to compensate for each component of the total written-in repeatable run-out error.

Abstract: A disc drive including rotatable disc surface adjacent a positionable read/write head having a write element offset from a read element in one direction across the rotatable disc surface from an outer diameter of the disc surface to an inner diameter of the disc surface for writing head position control fields by steps for controlling writing of second head position control fields on a second portion of the disc surface while reading head position control fields written on a first portion of the disc surface, using the read element, to augment position-control of the write element being controlled by a position information writing apparatus, while writing the second head position control field to the second portion of the disc surface.

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: In a large-capacity FD comprising a disk-shaped recording medium on which a plurality of tracks are arranged with concentric circles, each track is divided into a predetermined number of sectors having a length equal to one another. Each sector consists of a serve field and a data field. The servo field in each sector includes a sector number field in which a sector number and alternation contents of the magnetic disk medium are written and a track number field in which a track number is written. The sectors on each track may be assigned with serial sector numbers in a circumferential direction in order with skipping over any defective sector. The plurality of tracks may be separated in a radial direction into a plurality of zones each including at least one alternate track.

Abstract: A method and system for determining data sector splits across servo bursts in a disc drive having a data disc with an embedded servo configuration. The disc drive includes a data transducer selectively positionable over the data disc for transferring data to and from the data disc, and the data disc includes a plurality of zones of predefined tracks. The method includes locating one or more frame table parameters based on a new zone position, creating a plurality of new frame table entries, while the disc drive is in operation, based on the frame table parameters, and moving the data transducer from a past zone position to the new zone position. The disc drive includes parameter memory and frame table memory. The parameter memory contains a plurality of zone records, with the zone records containing a plurality of zone table parameters. The frame table memory is utilized to store a frame table.

Abstract: A method of detecting a position on a disk is applied to a disk which is time-divisionally recorded with a data region and a servo region based on a signal read from the disk, where the servo region is recorded with a servo pattern having a length of consecutive “0”s longer than a length of consecutive “0”s existing in the data region, and the servo pattern has three or more zones with consecutive “0”s. The method includes the steps of (a) digitizing the signal read from the disk and slicing at a predetermined level so as to convert the signal into “0” or “1”, and (b) detecting the servo pattern when two zones with consecutive “0”s are detected from information converted by the step (a).

Abstract: An actuator driving method and an actuator driving device for PWM-driving an actuator of a storage disk device are disclosed. This method and device prevent a servo signal from being overlapped with switching noises. The storage disk device includes a head for reading information from a storage disk, a PWM driver for generating a drive current having a pulse width corresponding to a current indication value, a linear driver for generating a drive current of which a magnitude corresponds to the current indication value, an actuator, driven by the drive current, for moving the head, and a control circuit for generating the current indication value for positioning the head from the servo information read by the head from the storage disk. The driving method includes a step of PWM-driving the actuator by the PWM driver, and a step of effecting a switchover from the PWM drive to a linear drive by the linear driver during a period for which the control circuit reads the servo information.

Abstract: An apparatus and method for correcting static track spacing errors in a data storage device having a plurality of concentric servo tracks. The data storage device includes a disc having a plurality of concentric servo tracks, an actuator assembly including a head adjacent the disc, and a controller operable for controlling the position of the head relative to the disc and operable to determine a correction factor indicative of a static track spacing error between servo tracks. The correction factor is used during operation of the data storage device to generate a corrected position signal for use by the data storage device in positioning the head with respect to the disc.

Abstract: A method and apparatus for controlling the position of a computer hard disk drive transducer head are provided. According to the invention, an initial value compensation scheme is applied to a signal derived from available states of the transducer head when the control mode of the disk drive switches from a track seek mode to a settling mode. In particular, at least portions of a the compensation signal are provided to both a coarse actuator and a microactuator associated with the transducer head. According to one embodiment of the present invention, high frequency components of the compensation signal are generally provided to the microactuator, while low frequency components of the compensation signal are generally provided to the coarse actuator. The method and apparatus of the present invention provide a computer hard disk drive having improved performance due to reduced settling times and improved audible characteristics.

Abstract: The present invention is a method of correcting radial position error signal (PES) values by utilizing predetermined error correction values located at predetermined locations in advance of their associated servo fields. Calculated correction values are written to zero-acceleration path (ZAP) fields on the disc during the manufacture process. ZAP fields are positioned before the servo fields whose PES they are designed to correct. The ZAP field is comprised of two or more correction data elements to correct subsequent PES values. As the read/write head flies along a track, it reads a ZAP field, and stores the PES correction data in local random access memory (RAM). Subsequently, the corresponding servo field is read and the stored PES correction data is used to correct the PES. Two types of ZAP fields are written on the disc—one type for read operations, another type for write operations.

Abstract: The present invention relates to a head positioning method and device for positioning a head to read information from disk media at prescribed positions using a rotary actuator, in which ch eccentricity errors of the rotary actuator are corrected. In a disk device having disk media (2), a head (3), a rotary actuator (5), and a control circuit (8), memory (11) is provided to store eccentricity correction information for each of the regions of a disk divided in the radial direction; eccentricity correction information corresponding to the head position is read, and eccentricity correction signals are created. Optimal eccentricity correction corresponding to the position of the head on the disk is made possible, and rapid seeking is enabled.

Abstract: The present invention relates to a head positioning method, its and a disk device for positioning the head to read a disk medium at a predetermined position, which demodulates accurate demodulation positions even when the head is moving. In a disk device comprising a disk medium (6), a head (4), an actuator (3) and a control circuit (19), the demodulation result is determined from the position signal of the head and speed is corrected by a correction value which depends on the moving speed of the head. Since the speed is corrected, accurate positions can be demodulated even when the head is moving.

Abstract: A disk for a disk drive system includes a disk having a track format region including a spoke field region. The spoke field region has a single binary bit to identify angular position of a track with respect to disk head of the disk drive system.

Abstract: A method and apparatus for detecting changes in clearance between a read/write transducer and a data storage medium involves acquiring a readback signal from the data storage medium using the transducer, the readback signal comprising one or more isolated pulses, and detecting a change in spacing defined between the transducer and the data storage medium using a slope of an edge of one or more of the isolated pulses.

Abstract: A method of detecting a position on a disk is applied to a disk which is time-divisionally recorded with a data region and a servo region based on a signal read from the disk, where the servo region is recorded with a servo pattern having a length of consecutive “0”s longer than a length of consecutive “0”s existing in the data region, and the servo pattern has three or more zones with consecutive “0”s. The method includes the steps of (a) digitizing the signal read from the disk and slicing at a predetermined level so as to convert the signal into “0” or “1”, and (b) detecting the servo pattern when two zones with consecutive “0”s are detected from information converted by the step (a).

Abstract: In the sector number counting method of the HDD using a disk as the recording medium having a plurality of servo sectors which are divided into several servo sectors groups, so that the first sector number information of each of the divided sectors groups is recorded on an index region, the inventive method for counting the sector number according to the present invention comprises the steps of checking whether the index bit recorded on the index region is detected every time when a servo interrupt occurs, and counting and saving the sector number according to a count value of an index timer on the basis of the first sector number of the servo sectors group corresponding to the index bit after the index timer is started when the index bit is detected.

Abstract: The present invention relates to an information storage apparatus for storing information in a recording medium and to a data transfer method. A particular object of the present invention is to provide an information storage apparatus and a data transfer method, which realize a high-speed transfer of control parameters without deteriorating performance of a control operation. The present invention includes an automatic transfer processing part 102 which transfers control parameters stored in a memory 15 by DMA transfer to an RDC 9, a servo information demodulation circuit 10, a head IC 8, and a DSP 17. The memory 15 is connected to an MCU 101 which controls a read/write operation of a magnetic disk unit 100.

Abstract: A disk drive system having a disk used to store information is disclosed. In one embodiment, the disk includes a servo track having a servo track pitch and a data track having a data track pitch. The servo track pitch and the data track pitch are unequal to one another. A method of reading data from a disk is also disclosed. The method includes the steps of: (1) providing a plurality of servo tracks, each having a track number; (2) providing a plurality of data tracks each having a data track number, wherein the number of servo tracks within a particular region of a disk are related to the number of data tracks within the particular region by a ratio defined as a TPI scale factor; (3) obtaining instructions from a host to read from a particular data track number; and (4) determining which servo track number should be used to access the particular data 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

Abstract: A disk type recording and reproducing apparatus includes a disk type recording medium having a plurality of tracks and having stored on each of the plurality of tracks a position signal indicating positions on the tracks; a drive section for rotating the disk type recording medium; a dual head separately incorporating a reading head for reading from the disk type recording medium and a writing head for writing into the disk type recording medium; a head drive section for moving the dual head; means for controlling the head drive section by a controlled variable in compliance with a position signal read from the disk type recording medium using an object track and the reading head; and memory means for storing quantity information used to correct the controlled variable of the means for controlling the head drive section.

Abstract: A method of determining the subtrack within zone P on a recording medium is provided. The recording medium has a plurality of zones 1 through Q. Each zone has a plurality of subtracks 0 through M. Each subtrack has a plurality of sectors 0 through N. Each sector has a position identifier field. Each position identifier field has a plurality of information units for recording a position identifier. The position identifier for Jth sector of subtrack I is identified as S(I,J). A preferred method comprises obtaining the local subtrack value as S(I,0), a space-efficient way to store and extract subtrack location information.

Abstract: A technique for formatting a magnetic disk for a removable magnetic cartridge includes the steps of providing the magnetic disk having a top surface and a bottom surface, writing a first servo track onto the top surface, the first servo track having a portion including a first gray code, a first position burst, and a second position burst, writing a second servo track onto the top surface adjacent to the first servo track, the second servo track having a portion including a second gray code, the second position burst, and a third position burst, and writing a third servo track onto the top surface adjacent to the second servo track, the third servo track having a portion including the second gray code, the third position burst and a fourth position burst, wherein a first data track comprises the first servo track, the second servo track and the third servo track.

Abstract: A direct access storage device that (DASD) includes a sector servo control system that controls disk write operations by receiving a servo pattern readback signal in a sector, determining track centering for that sector, and generating a write inhibit signal before any write operations are initiated for that sector. The servo control system is able to make write inhibit decisions without software processing delays, enabling the system to produce a write inhibit signal quickly after an off-track excursion, and to terminate a write inhibit decision quickly after it is no longer needed.

Abstract: An unlatch control technique for enabling a hard disk drive to perform well a following sequence with a stable speed of a head being maintained after a head is unlatched by adjusting an unlatching deceleration current includes the steps of: detecting servo information written in a sector on a predetermined track of a disk when controlling the unlatching operation of the head; calculating the speed of the head which is unlatched by using the servo information; and adjusting the unlatching current depending on the head speed. Since the unlatching current can be adjusted through the feedback process of the head speed in the control of the unlatching operation, a more stable unlatching operation is accomplished.

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 synchronous digital demodulator and method for demodulating a read signal including a user data waveform and a servo waveform which are generated by a read head as the read head passes over a user data area and a servo area, respectively, on a medium in a storage device. The user data waveform is converted to a series of digital user data values at a user data sample rate. The series of digital user data values are then applied to a user data detector circuit. The servo waveform is converted to a series of digital servo values at a servo sample rate, which is independent from the user data sample rate. The series of digital servo values are demodulated synchronously with the servo waveform to produce a position error value indicative of a position error of the read head relative to a location on the medium.

Abstract: A signal processing device having a feature of analog-to-digital converting a burst signal has a feature of selecting a data bus to notify a disk control device of a conversion result via an NRZ data bus. The disk control device stores the result of the analog-to-digital conversion of the servo positional signal. The positional signal of a head of the disk device is digitalizes in a R/W channel. Sampling for digital conversion is performed in only a window which is defined only in the vicinity of peaks of the positional signal. The values of peaks which are obtained by sampling are averaged by an averaging circuit. This enables the influence of noise occurred outside of the window to be eliminated. Although the noise in the window is sampled, its adverse influence is suppressed by the averaging processing.

Abstract: A data storage apparatus includes a servo controller (160) coupled to an actuator (190). The servo controller (160) provides control command signals to the actuator (190) to move a head from an initial position to a final position at a discrete time interval. A method of moving at least one head of a disk drive is also provided. The method includes the step of moving the head from an initial track to a final track without utilizing a separate track acquisition operation to position the head over the final track.