Abstract: A method and apparatus to quickly and correctly re-initialize a tape drive mechanism after power loss employs a non-volatile memory to store functional state data during normal operation of the tape drive mechanism. After a power loss, the functional state data is read from the non-volatile memory so that the tape drive mechanism can be properly re-initialized based on the recovered functional state data.

Abstract: An apparatus for detecting an abnormality of a recorded signal of a recorder/player includes a plurality of recording/reproducing heads for recording/reproducing a signal onto/from a medium, and a determining portion for determining an abnormality of the recorded signal based on the signal reproduced by the recording/reproducing heads. While one recording/reproducing head records the signal of image and/or sound on the medium, the other recording/reproducing head reproduces the signal recorded by the recording/reproducing head. The determining portion determines the abnormality of the recorded signal by determining whether or not the signal reproduced from the medium is in a normal data format, or by determining whether or not an envelope of reproduced signals is greater than a predetermined level. Accordingly, when abnormality of recorded signal occurs due to a presence of foreign substances on the heads or from other problem sources, a user is immediately notified of such an abnormality.

Abstract: A thinfilm magnetic head for tape drives that enables onsite, real time temperature monitoring of the head-media interface. The head includes a media interface contacting a data bearing surface of the tape. A thinfilm, read-write element and a thinfilm sensor of a thermosensor are positioned on the head-media interface. The thermosensor generates a signal based on the temperature of the media interface. The media interface includes an active island and an optional inactive island positioned transverse to the tape travel path with the read-write element in the active island. The sensor may be placed on the inactive island or on the active island adjacent the read-write element. In one embodiment, a plurality of read-write elements and thermosensors are provided and sensors of the thermosensors are positioned on the inactive island and/or the active island among or between the read-write elements or adjacent an end element.

Abstract: A storage system capable of reducing the start-up time of disk drives is provided. If a power source monitor circuit itself is normal (S93), the power source monitor circuit reads a detection signal from a detection circuit, and checks power sources (S94). If the power sources are normal (S95), all disks are spun up (S96). When the spin-up of all disks is completed (S98), processing is completed. If either of two power sources fails (S95), the power source monitor circuit reports the fact to a host control logical part (S99). The power source monitor circuit clears its internal counter to zero (S100) and issues a drive command to HDDs (S101). When the spin-up of all disks is completed (S103), processing is completed. If there is a disk which has not yet been spun up, the power source monitor circuit sets the internal counter to n+1 (S104) and returns to Step S101.

Abstract: The present invention provides a method and apparatus for recovering data in a disk drive following a read error. At least a portion of the actuator arm tip is heated. Thermal expansion reduces the read-head-to-disk spacing, increasing the likelihood of success when a re-read of the data is attempted. In one approach, a heater is operatively coupled to the tip. In one aspect, a write head is provided with write current in order to heat the tip. Data which may be modified or overwritten when providing write current to the write head is preferably read and buffered prior to the write operation, for later re-writing to the disk.

Abstract: The present invention provides a tape drive apparatus enabled to directly and accurately detect dew condensation on a rotary head drum. Tape serving as a recording medium is drawn out of a cartridge. The drawn tape runs in such a way as to be wound on a tape takeup reel provided in a tape drive apparatus body. Signals are recorded on and reproduced from the tape by winding the drawn tape around the rotary head drum. This tape drive apparatus has a prethreading mechanism that brings the tape into slight contact with the rotary head drum before the tape is completely wound therearound. Dew condensation on the rotary head drum is detected by rotating the rotary head drum during a status in which the tape is brought by the prethreading mechanism into contact with the rotary head drum.

Abstract: Tape drive systems and methods for operating tape drive systems are provided. The system includes a head assembly having a head element for reading or writing data to a magnetic tape medium, and a pressure sensor coupled to the head element, the pressure sensor configured to generate a pressure signal representative of a pressure applied by the head element onto the pressure sensor. In some embodiments, an accelerometer is provided for sensing an acceleration of the head assembly and for generating a acceleration signal representative of an acceleration experienced by the head assembly. The method includes passing a tape medium between a take-up reel and a supply reel such that a tension in the tape medium causes the tape medium to apply a pressure onto a head element, and using a pressure sensor to detect a pressure applied by the head element onto the pressure sensor.

Abstract: A system, method and program are disclosed for automatically exchanging tape cartridges between a plurality of automated tape libraries arranged in close proximity. The automated cartridge exchange system translates a forward and reverse stroke in a first axis directed parallel to the sidewalls of two adjacent tape libraries to a radial movement directed to a second axis perpendicular to the first axis and into and out of the tape libraries (e.g., via a pass-through port in each library). Thus, the cartridge density of the overall library system is maximized by limiting the width of the main assembly of the automated cartridge exchange system and thereby minimizing the distance between the two adjacent libraries. Also, the automated cartridge exchange system can be blind-mated to the adjacent libraries and thus provide a hot-swappable (on-line), readily serviceable component that is not available from the existing approaches.

Abstract: A media-detection system and method for identifying a type of data cartridge. According to one embodiment, the media-detection system comprises at least one indicator arm displaceable by at least one surface feature of the data cartridge as the data cartridge is loaded in a cartridge-receiving device. The media-detection system also comprises at least one sensor detecting the displacement of the at least one indicator arm as the data cartridge is loaded, thereby indicating the type of data cartridge in the cartridge-receiving device.

Abstract: A spindle motor in a disk drive is driven by a driving circuit that, upon receipt of a signal or command, selectively spins up the spindle motor according to a first spin up profile or according to a second spin up profile that is defined to provide a longer spin up time in comparison with the spin up time defined by the first spin up profile. The second spin up profile spins up the spindle motor in a longer period of time and/or generates less acoustic noise as compared to the first spin up profile.

Abstract: A servo system for displacing a head relative to a disk of a hard disk drive. The servo system comprises a dual-stage actuator, a calibration signal generator, and a calibration factor generator. The calibration signal generator generates a calibration signal having a calibration portion. The calibration factor generator generates a calibration factor. The servo system operates in operating and calibration servo modes. In the operating mode, the system defines first and second servo loops. The calibration factor is used as one of the parameters of the second servo loop. In the calibration servo mode, the calibration signal forms the second control signal, and the calibration factor generator generates the calibration factor based on movement of the head before any substantial response of the third servo loop to the calibration portion.

Abstract: When the data recording is performed on a magnetic tape in various recording densities, information relating to the recording density (recording-density related information) is recorded in the data recorded on the magnetic tape. Accordingly, recording and reproduction can be properly managed by referring to the recording-density related information, even if data in various recording densities are recorded on the same magnetic tape. Further, when the recording density is altered, the drive apparatus side switches over the recording density in accordance with the quality of recording data. Thus, in the case where the data writing is not possible due to a recording error, the recording density is switched over to a lower recording density to record the data without an error, and therefore a higher flexibility is provided to a data format to be recorded on the magnetic tape.

Abstract: A method and apparatus for compensating for media shift due to spiral groove roller tape guide is disclosed. The lateral tape shift is measured. Then the control of the coarse actuator is adjusted for the lateral tape shift so that the movement of the coarse actuator follows the tape shift.

Abstract: A hard disk drive energy recovery circuit, a method of recovering energy from a motor of a hard disk drive and a hard disk drive. In one embodiment, the hard disk drive energy recovery circuit includes (1) a spindle resolver that generates transition signals as a spindle motor of the hard disk drive rotates among angular regions, (2) a spindle region state machine, coupled to the spindle resolver, that receives the transition signals and generates rectifier drive signals based thereon and (3) a synchronous rectifier, coupled to the spindle region state machine, that employs the rectifier drive signals to recover electrical energy from the motor.

Abstract: A method for adjusting a tape wrap angle is described comprising the steps of operating the tape system to generate or regenerate an electrical signal in the head from the tape, either increasing or reducing the tape wrap angle as appropriate until a signal from the tape head reappears or goes to zero, then increasing the wrap angle until the desired angle is achieved as measured by the signal from the head or by moving the tape support a fixed amount. A tape recording and/or reading system with adjustable wrap angles is described which can be used with the method of the invention. The system includes one or more rollers mounted on an adjustable shaft with an eccentric or axially offset portion supporting the roller. Preferably for a two or multibump head an adjustable shaft and roller according to the invention are located on the tape-in and tape-out side of the tape head.

Abstract: In a video tape recorder (VTR), the capstan draws the tape from which the video signal is reproduced in a forward direction. The following steps are used to control the capstan, applying a torque to the capstan in a backward direction for a first predetermined period of time. Applying a torque to the capstan in the forward direction for a second predetermined period of time and nullifying the motor current. This arrangement is particularly convenient for slow-motion and still-picture modes.

Abstract: A system and method of controlling tape tension during operation of a tape drive by making use of pre-existing timing based servo patterns formatted on the media. Changes in servo pattern timing are read at regular intervals and used to calculate changes in tension, with the torque of the tape reel motors being adjusted accordingly.

Abstract: In general, the invention is directed to techniques for reducing deformation of tape in data tape cartridges during storage to promote dimensional stability and increased tape longevity. The techniques involve controlling the winding tension applied to a tape during a final winding pass prior to unloading a data tape cartridge containing the tape from a drive. Excessive winding tensions can produce strain and compression on a tape pack, causing the tape to deform over time. Applications of reduced winding tension during the final pass provide reduced tape pack tension during periods in which the data tape cartridge is not used.

Abstract: A servo writer which writes a servo mend on a tape by the write head is characterized by being equipped with a pay-off side motor paying off the tape from tie payoff reel by rotating the pay-off reel; a winding side motor winding the tape on the winding reel by rotating the winding reel; a first capstan roller and second capstan roller which are provided at an upstream side and down stream side of the write head, respectively, and by rotating the capstan rollers, run the tape in a state pinched between respective pinch rollers and the capstan rollers; a first tension detector which is provided between the first capstan roller and second capstan roller and detects running tape tension; and a capstan roller controlling unit controlling a rotation speed of the first capstan roller and second capstan roller so that tension detected by the tension detector becomes constant.

Abstract: A method and apparatus are provided for implementing intelligent spin-up for a disk drive. When a command is received, checking for a disk drive start command is performed. Responsive to identifying the disk drive start command, a no-start flag is checked. Responsive to identifying the no-start flag being set, an error code is returned without starting the disk drive. The disk drive is started only when the no-start flag is not set. During operation of the disk drive, the disk drive is monitored to identify a drive fault condition. Responsive to identifying a disk drive fault, the identified disk drive fault is checked to identify a predefined inoperative drive or dead device fault. When a predefined dead device fault is identified, the no-start flag is set and an error code for the predefined dead device fault is stored. Also a no-load flag is set that is used when the disk drive is running to stop the disk drive and return an error code before the transducer heads are loaded.

Abstract: A thin-film write head employing pole pieces formed of an electroplated body-centered cubic (BCC) nickel-iron alloy with a saturation flux density (BS) of 1.9 to 2.3 T (19 to 23 kG) and an acceptable coercivity (HC) of about 80 to about 160 A/m (1-2 Oe). The iron content of the electroplated nickel-iron alloy is from 64% to 81% by weight. The two-layer pole fabrication process holds magnetic anisotropy and coercivity to useable values while improving saturation flux density and optimizing magnetostriction. This is accomplished by first electroplating a BCC nickel-iron layer onto an underlying seed layer and then annealing the two layers to reduce coercivity to less than about 160 amps/meter and raise magnetization to acceptable levels.

Abstract: To measure a lateral shift of running magnetic tape caused by a lateral movement of the magnetic tape which occurs while the magnetic tape is running, a fixed write head H1 of a measurement apparatus 10 magnetizes part of the running magnetic tape MT in a section of the apparatus 10 where the magnetic tape MT is free from restriction on lateral movement; a pair of guides 14, 14 in a tape guide unit of the apparatus 10 is located downstream of the fixed write head H1 to restrict the lateral movement of the magnetic tape MT; and a fixed read head H2 reads information recorded on the magnetic tape MT in the tape guide unit.

Abstract: Methods and devices for converting the kinetic energy of the rotating spindle motor of a disk drive of a rechargeable battery operated mobile host device into electrical energy during braking of the rotating spindle motor. The converted electrical energy is conditioned and used to charge the rechargeable battery of the mobile host device.

Abstract: A data storage device comprising a computer useable medium having computer readable program code disposed therein for writing information on a data storage medium using fast multiple file write operations. A data storage and retrieval system comprising one or more of Applicants' data storage devices. Computer program products embodied as program code stored in Applicants' storage device.

Abstract: A data storage magnetic tape uses a volume control region (VCR) that contains all of the control information for the tape. There is a large span of blank tape after the VCR region before the actual data storage region of the tape. When a tape drive spools the tape between the VCR and data storage region, the tape motion is continued past the VCR region, after the VCR region is updated, into the region of tape where there is no data of any kind. Just before reaching the data storage region, the motion of the tape is reversed and the tape is rewound into the cartridge. The portion of the tape that experiences the motion reversal is prone to be thrown such that it protrudes from the other layers of uniformly layered tape. Even if these thrown wraps are damaged, this portion of the tape has no stored data, which increases the overall reliability of the information stored on the tape.

Abstract: Calibration logic separately operates DC motors of a tape drive at a steady state estimated velocity (Omega C) for at least one full revolution without a tape; senses Hall sensor(s) to indicate a full revolution of each motor, measuring the time of the full revolution; determines the actual velocity (Omega A) of each motor employing the measured time; compares Omega C to Omega A to determine a calibration constant (K calib) for each motor; to calibrate the motor velocity of each motor, for determining the velocity for a mounted tape by averaging the tape velocity generated by each motor based on the calibrated motor velocity.

Abstract: A control system compensates for web tension variation caused by a first spool, (A) determines rotational frequency of the first spool; (B) determines variation in rotational velocity at the second spool which occurs at the (A) first spool frequency; (C) determines the rotational position at the first spool corresponding to the (B) variation in rotational velocity at the second spool; (D) calculates a drive motor profile for the first spool which tends to cancel the (B) variation in rotational velocity at the second spool; and (E) superimposes the (D) drive motor profile on a first spool drive motor at the (C) determined rotational position of the first spool.

Abstract: An apparatus and method for the controlled dynamic braking of a DC motor in a tape transport device are provided. A PWM state device includes a plurality of state transition paths, each path having an initial state, representative of a tape profile, including a predetermined range of tape velocities, relative amounts of tape on each reel and an initial tape tension, and at least one subsequent state. When a low power event is detected, one of the state transition paths is selected, based upon a current tape profile, and an associated PWM signal is transmitted to the motor. An energy storage device provides power to the PWM state device during the low power event. The PWM signals follow the selected transition path to modulate the current generated by the motion of the motor and thereby create a decelerating force while substantially maintaining the initial tape tension.

Abstract: Method and apparatus accomplishing an OPC (optimal power calibration) at a test area secured in data recording area of a writable optical recording medium and detecting an optimal writing power appropriate to the test area. The optimal writing power detecting method searches for a marginal area adjacent to a data section recorded on an optical recording medium, records test data on the marginal area discovered in the searching step while changing a writing power; and reproduces the test data recorded on the marginal area and determines an optimal writing power based upon the characteristics of the reproduction signal. The method and apparatus can reduce time required to move an optical pickup inward and outward to accomplish the OPC operation, from a recording request to practical data recording, while enhancing writing characteristics, since an optimal writing power is obtained from a test area close to the area for recording input data.

Abstract: A method and apparatus to quickly and correctly re-initialize a tape drive mechanism after power loss employs a non-volatile memory to store functional state data during normal operation of the tape drive mechanism. After a power loss, the functional state data is read from the non-volatile memory so that the tape drive mechanism can be properly re-initialized based on the recovered functional state data.

Abstract: A media-detection system and method for identifying a type of data cartridge. According to one embodiment, the media-detection system comprises at least one indicator arm displaceable by at least one surface feature of the data cartridge as the data cartridge is loaded in a cartridge-receiving device. The media-detection system also comprises at least one sensor detecting the displacement of the at least one indicator arm as the data cartridge is loaded, thereby indicating the type of data cartridge in the cartridge-receiving device.

Abstract: A playback error associated with overwriting on a narrow-width track is prevented from occurring in the overwritten portion. A signal generator (11) generates a signal of a predetermined data pattern that stabilizes the operation of a synchronizing pulse generator of a playback system (shown in a separate figure). A timing generator (4) switches over a switch (12) to the output of the signal generator (11), at least a period of time equivalent to writing of one track before the main signal is input. When a signal of the predetermined data pattern from the signal generator (11) has been output, the timing generator (4) switches over the switch (12) to the main signal. The playback system includes a circuit which discriminates between the predetermined data pattern and the main signal data from a playback signal generated by playing back a record on a magnetic tape (T).

Abstract: A data storage drive arranged as a plurality of logical accessors accesses data on a removable random access medium. Upon a write access for a data segment by a logical accessor, a control locks a context comprising at least one data segment of a partition to the logical accessor. The control concurrently allows read access to the data of the removable random access medium, except the locked context, and allows write access, except to the locked partition, by other logical accessors.

Abstract: Hard disk drive unit with buffer and cue data areas efficiently records files to magnetic tape. Recording and reproducing apparatus includes changer unit for selecting and carrying tape cassettes and accommodating magnetic tapes with predetermined recording areas, tape drive unit for loading tape cassettes and recording and reproducing magnetic tapes, hard disk drive unit having a buffer area for recording and reproducing data in the tape drive unit, and controller unit for managing recording areas of tape cassette magnetic tapes arranged in the changer unit as a continuously formed area. Storage level is set corresponding to remaining capacity of buffer area and remaining capacity of one BOF data area, or number of past access times to corresponding file in a file information table and final access time, etc. Based on storage level, control operations are performed. Frequently used file data can be selectively recorded to buffer or BOF data areas.

Abstract: According to one embodiment of the present invention, a method of counteracting gas ingestion in a hydrodynamic bearing of a spindle motor in a data storage device comprises waiting for activity of a host connected with the data storage device to become idle. When the activity of the host becomes idle, a determination is made whether to release gas from a fluid of the hydrodynamic bearing of the spindle motor. Responsive to determining to release gas from a fluid of the hydrodynamic bearing of the spindle motor a motor spin down routine for the spindle motor is performed.

Abstract: A method and apparatus to monitor the positioning of a tape leader pin in a tape threader block moveably disposed in a tape drive. The' apparatus includes a tape threader block assembly comprising a first circuit having a first coil, a second circuit having a second coil, where that second circuit has an impedance, where the first coil is disposed adjacent the second coil. The apparatus further includes a detection circuit which detects the impedance of the second circuit, where the second circuit has a first impedance when the first circuit is open, and where the second circuit has a second impedance when the second circuit is closed. In the event a tape leader pin is properly releaseably fixtured to Applicants' threader block, the first circuit is closed and the impedance of the second circuit changes. The detection circuit detects that impedance change and provides a signal to a controller indicating that the tape leader pin is properly seated in the threader block.

Abstract: A system and method of controlling tape tension during operation of a tape drive by making use of pre-existing timing based servo patterns formatted on the media. Changes in servo pattern timing are read at regular intervals and used to calculate changes in tension, with the torque of the tape reel motors being adjusted accordingly.

Abstract: A method for adjusting a tape wrap angle is described comprising the steps of operating the tape system to generate or regenerate an electrical signal in the head from the tape, either increasing or reducing the tape wrap angle as appropriate until a signal from the tape head reappears or goes to zero, then increasing the wrap angle until the desired angle is achieved as measured by the signal from the head or by moving the tape support a fixed amount. A tape recording and/or reading system with adjustable wrap angles is described which can be used with the method of the invention. The system includes one or more rollers mounted on an adjustable shaft with an eccentric or axially offset portion supporting the roller. Preferably for a two or multibump head an adjustable shaft and roller according to the invention are located on the tape-in and tape-out side of the tape head.

Abstract: A method and apparatus for performing position error signal conditioning of LTO media servo format written-in velocity variation is disclosed. According to the present invention only the signals demonstrating velocity deviations are filtered. A magnetic recording tape includes servo signal bursts of flux transitions recorded thereon. The servo bursts include a configuration of stripes of A spacings and B spacings and a servo head disposed proximate to the magnetic recording tape senses the flux transitions of the servo signal bursts. A servo controller, coupled to the servo head, receives the sensed signals from the servo head. The servo controller further includes a filter for filtering the B time interval servo signal components. Then a position error signal according to: PES=ref−A/(B filtered), wherein A represents unfiltered A time interval servo components and B filtered is filtered B time interval servo components.

Abstract: In an essentially flat contour linear tape recording head, a nominal tape wrap angle exists at which reading signals from the magnetic tape ceases and/or commences. This nominal tape wrap angle can be easily determined by monitoring a prerecorded signal, such as the servo track signal, while the tape wrap angle is adjusted. When the signal ceases (or starts, depending upon the direction of adjustment) an initial position of the tape movement control device relative to the tape wrap angle is identified. At this initial position it is known that the tape wrap angle is at its nominal value, such as approximately 0.1°. Thereafter, the tape movement control device can be knowingly adjusted with a calibrated indicator to accurately and quickly achieve a desired final tape wrap angles.

Abstract: A method of recovering data from a data sector through adaptive fly height to improve reliability of a disc drive is disclosed. Encountering a data error in a data sector initializes an error recovery routine that increases a fly height of the read/write head for asperity encounters, or decreases the fly height of the read/write head for low amplitude read signal encounters. In the case of asperity encounters, when the increased fly height fails data recovery, the read/write head is positioned off track, then lowered to burnish the asperity and the data sector is re-read.

Abstract: A method for calibrating a tape transport servo system for a tape drive is disclosed. The tape reel motors are excited when the tape drive is not being controlled by the tape transport servo system. Then, calibration data is collected for the motor torque, motor friction, DAC offsets, and pulse width modulator control signal timing.

Abstract: A tape movement constraint is provided for a tape drive system which moves a tape longitudinally along a tape path across a tape head, the tape having longitudinal tracks. The tape head has a track following servo system for moving the head laterally for following lateral movement of the tracks, where the tape is subject to lateral transient movement. A tape roller bearing closely adjacent the tape head is rotatable about a central axis parallel to the cylindrical peripheral surface, allowing the tape freedom of movement in the longitudinal direction. The tape roller bearing has a frictional cylindrical peripheral surface for contacting and engaging the surface of the tape and constraining movement of the tape in the lateral direction, thereby reducing the rate of the lateral transient movement of the tape to allow the track following servo system to follow the reduced rate lateral transient movement of the longitudinal tracks.

Abstract: The present invention provides a tape drive apparatus enabled to directly and accurately detect dew condensation on a rotary head drum. Tape serving as a recording medium is drawn out of a cartridge. The drawn tape runs in such a way as to be wound on a tape takeup reel provided in a tape drive apparatus body. Signals are recorded on and reproduced from the tape by winding the drawn tape around the rotary head drum. This tape drive apparatus has a prethreading mechanism that brings the tape into slight contact with the rotary head drum before the tape is completely wound therearound. Dew condensation on the rotary head drum is detected by rotating the rotary head drum during a status in which the tape is brought by the prethreading mechanism into contact with the rotary head drum.

Abstract: An apparatus for detecting an abnormality of a recorded signal of a recorder/player includes a plurality of recording/reproducing heads for recording/reproducing a signal onto/from a medium, and a determining portion for determining an abnormality of the recorded signal based on the signal reproduced by the recording/reproducing heads. While one recording/reproducing head records the signal of image and/or sound on the medium, the other recording/reproducing head reproduces the signal recorded by the recording/reproducing head. The determining portion determines the abnormality of the recorded signal by determining whether or not the signal reproduced from the medium is in a normal data format, or by determining whether or not an envelope of reproduced signals is greater than a predetermined level. Accordingly, when abnormality of recorded signal occurs due to a presence of foreign substances on the heads or from other problem sources, a user is immediately notified of such an abnormality.

Abstract: In a floppy disk drive having a main frame in which a floppy disk is inserted and a DD motor for rotatably driving the floppy disk inserted in the main frame, the floppy disk drive has a motor frame for mounting the DD motor thereon that is constituted by one piece integrated by the main frame. Preferably, the motor frame part may have a drawn-shape obtained by drawing the main frame. In addition, the floppy disk drive has an electronic processing arrangement for a frequency generation pattern. The electronic processing arrangement gives play to a function equivalent to the frequency generation pattern required to control the DD motor.

Abstract: Each of data bands of a magnetic tape includes a plurality of wraps as data tracks. In the read/write test, a predetermined test length is set to every wrap and test patterns are written to the test length portion, and the patterns are read so as to verify whether or not there is trouble to the drive or the tape. While it takes time to switch a magnetic head among the wraps on testing all the wraps, the time depends on order of switching. In the present invention, the order in which the magnetic head switches the wraps for reading or writing, that is, a wrap sequence, is selected to be different from the wrap sequence in an actual active state. The wrap sequence in the actual active state has been selected based on a factor such as writing performance of the tape, which has not been suited to the read/write test.

Abstract: A hard disk balancing apparatus for a hard disk drive including an eccentricity detection unit to detect an eccentricity amount and an eccentricity position of the hard disk with respect to a rotation axis of a spindle motor for rotating the hard disk as an origin, and a pushing unit to push a circumference of the hard disk in the eccentricity position and to move the hard disk on the rotation axis of the spindle motor according to the eccentricity amount. Here, the eccentricity detection unit includes a detection sensor to detect the rotation axis of the spindle motor, and is placed coaxially with the rotation axis of the spindle motor, and at least three distance sensors that are separated from the detection sensor to be at least farther than a radius of the hard disk and to measure a distance between one point on the outer circumference of the hard disk and themselves.

Abstract: A disk drive includes a disk from and to which information can be read and written; a disk driving motor for spinning the disk; a read/write head disposed in the vicinity of the disk; a head transfer mechanism for transferring the read/write head in the radial direction of the disk; and a controller for controlling the overall disk drive. The disk drive is connected to a host control unit through a Universal Serial Bus interface. When a step signal for driving the head transfer mechanism is output at a point at which the disk driving motor is activated, the controller immediately deactivates the disk driving motor and only actuates the head transfer mechanism to move step by step.

Abstract: A dual GMR or dual spin valve sensor has a self-pinned layer which has its magnetic moment pinned perpendicular to an air bearing surface by sense current fields from conductive layers in the dual spin valve sensor when a sense current is conducted therethrough. This scheme eliminates one of the antiferromagnetic pinning layers which is typically employed in a dual GMR or dual spin valve sensor. The self-pinned layer is thin so that its demagnetization field will not be greater than the sense current fields acting thereon. Because of the thinning of the self-pinned layer the spin valve effect of the spin valve sensor is degraded by scattering of conduction electrons at the boundary of the self-pinned layer.