Abstract: A read circuit for providing multi-bit disk data to a disk controller in correspondence to analog data from a disk head, includes a low frequency clock generator whose phase is adjustable in response to a detection of the synchronization marker in the analog disk data. A high frequency clock is phase-locked to the output of the disk head, and synchronizes operation of an A/D converter and a bit detector which produces a verified single-bit based on the A/D output. A serial-to-parallel converter converts the single bit output from the bit detector to a parallel output, and the parallel output is latched to multi-bit disk data for use by the disk controller in accordance with a low frequency clock. The low frequency clock is generated by a clock generator from the high frequency clock with a phase that is adjustable in response to the synchronization mark detector.

Abstract: A magnetic transfer method for transferring a magnetic recording information on a master carrier for magnetic transfer to a slave medium by bringing the master carrier for magnetic transfer with a magnetic layer with magnetic recording information recorded thereon into close contact with the slave medium where the information is to be transferred, whereby initial DC magnetization is performed on the slave medium in advance in track direction, and using a magnetic material having a product (Ms·?) of saturation magnetization (Ms) and magnetic layer thickness (?) within the range of 0.025 T·?m (20 G·?m)–2.3 T·?m (1830 G·?m) inclusive as the master carrier for magnetic transfer, the slave medium after the initial DC magnetization is brought into close contact with the master carrier, and a magnetic field for transfer is applied in a direction opposite to the direction of the initial DC magnetization of the slave surface, and magnetic transfer is performed.

Abstract: The present invention is directed to a method and apparatus for reducing off-track writes in a data storage device. In one embodiment, a command is received to perform a write operation using a write head at a first location on a disk surface. A determination is made as to whether to perform or inhibit the write operation using an equation having a tunable acceleration coefficient. The equation is used to predict a position error signal (PES) value for a write head at a servo sector that immediately circumferentially follows the first location (i.e., there are no intervening servo sectors between the servo sector and the first location). If the predicted PES value is outside of (e.g., greater than or less than) a predetermined threshold, an off-track write is likely to occur and the write operation is inhibited.

Abstract: There are provided a magnetic head and a magnetic disk apparatus wherein an upper magnetic pole is so shaped that, at a position where skew angle is maximum, the maximum of its projected length in the radial direction of a magnetic disk is not more than the track pitch of the magnetic disk, whereby acceleration of thermal relaxation of information recorded on adjacent tracks is obviated even in an area where the skew angle is large.

Abstract: A disk drive includes an actuator assembly having a read/write head, a spindle motor, a disk mounted for rotation on the spindle motor, a wedge-to-wedge timer and a sector size selector. The disk includes a recording surface having a plurality of tracks and each track includes a plurality of servo wedges. The recording surface has at least one data sector between circumferentially adjacent servo wedges on each track. The wedge to wedge timer measures the time elapsed between at least two successive detections of circumferentially adjacent servo wedges and outputs a wedge-to-wedge correction signal that is dependent upon the measured elapsed time. The sector size selector outputs a sector size signal that changes according to the wedge-to-wedge correction signal. In turn, the sector size signal determines the size of the next data sector on the recording surface of the disk.

Abstract: A disk drive provides temperature compensation for write current. The write current not only provides an acceptable bit error rate for data written to and read from the disk, but also prevents write induced instability in the head. Furthermore, the write current prevents excessive pole tip protrusion. As a result, the write current ensures that data is reliably stored and retrieved at a given temperature.

Abstract: A method and system of switching heads in a hard disk drive written using an off-line STW method. In the method, first, deviations between a reference head and each of the heads are calculated. Next, a mapping table having the deviations between the reference head and each of the heads is generated and stored in a memory. Thereafter, when a head switching operation is requested, a current head is switched to a new head to access a track whose number is the same as the track assessed by the current head. A deviation of a track on which the head is positioned, recorded in the mapping table, is applied to the virtual track address of the track on which the head is positioned, thereby obtaining the physical track address of the track on which the head is positioned. The requested track is then accessed based on the obtained physical track address.

Abstract: A tape recording apparatus for recording data on a tape medium is provided with: a data writing unit for writing a data unit to the tape medium, and if an error is detected in the writing of the data unit, writing the same data unit to the tape medium again and recording a plurality of the data units sequentially; a write number counter for, in a data set including the plurality of data units, counting a write number which is a number of writing the data units; a write number information storage unit for storing write number information, in which information indicating the counted write number and a physical position in the tape medium are associated with each other, with respect to a plurality of the tape media to which the above described tape recording apparatus has written; and a failure determination unit for detecting a failure in the data writing unit based on the write number information.

Abstract: A servo circuit includes a servo channel and a processor. The servo channel recovers servo data from servo wedges that identify respective data sectors on a data-storage disk. On spin up of the disk, the processor detects a spin-up wedge associated with one of the servo wedges and then detects the servo wedge. Once the servo wedge is detected, a head-position circuit can read the location data from the servo wedge to determine an initial position of the read-write head. By detecting a both a spin-up wedge and a servo wedge to determine an initial head position on disk spin up, such a servo circuit often allows one to increase the disk's storage capacity by reducing the lengths of the spin-up wedges.

Abstract: A signal processing apparatus which is capable of reducing the occurrence of noise at editing points without the need to decode an encoded audio signal when editing the encoded audio signal. A recording/reproduction section reproduces an audio signal sequence including an audio signal encoded according to normalization information for controlling amplitude of the audio signal, and the normalization information. A normalization information converter changes the normalization information of the reproduced audio signal sequence.

Abstract: Asymmetry correction for an MR read head in a magnetic recording channel employs an exponential function to correct MR read head asymmetry. The asymmetry correction function has the form fASC (y)=y?q(eay+e?ay?2), wherein a is a parameter that can be adjusted for optimal channel performance, and q is an asymmetry correction coefficient.

Abstract: A method of evaluating the positioning accuracy of a magnetic head tester can accurately test magnetic heads and so can reliably provide non-defective goods. In a method of evaluating the positioning accuracy of a magnetic head tester that tests the performance of a magnetic head 14 by carrying out writing and reading operations on a magnetic medium 12 using the magnetic head 14. A plurality of GAPS profiles are acquired by repeatedly carrying out a GAPS test that measures a GAP offset amount for the same magnetic head 14 that has been attached to the magnetic head tester, a GAP offset fluctuation amount is calculated from the acquired plurality of GAPS profiles, and the calculation result is set as an index for evaluating the position reproducibility of the magnetic head.

Abstract: A rotatable storage media includes a first data segment stored in first tracks and a second data segment stored in second tracks. The first tracks include a first start track and a first end track, and the second tracks include a second start track and a second end track. The first data segment starts in the first start track at a start rotational phase, ends in the first end track at an end rotational phase, starts in adjacent first tracks at start rotational phases offset by an intra-segment rotational skew angle and ends in adjacent first tracks at end rotational phases offset by the intra-segment rotational skew angles. The second data segment starts in the second start track at the start rotational phase, ends in the second end track at the end rotational phase, starts in adjacent second tracks at start rotational phases offset by the intra-segment rotational skew angle and ends in adjacent second tracks at end rotational phases offset by the intra-segment rotational skew angle.

Abstract: An apparatus and a method to remove a resonance frequency of a system in which an unnecessary resonance frequency occurs in a head stack assembly (HSA) having a head for reading/writing data. The HSA is identified and filtered to prevent mechanical damage caused by resonance. The system is artificially excited to identify a potential resonance frequency of the system. The system is designed so that the identified resonance frequency is filtered. Thus, resonance frequency components outside of Nyquist frequency bandwidth of the system can also be identified. Also, the resonance frequency can very easily be identified in a time domain without a complicated calculation process such as an additional frequency transformation process. Coefficients of a programmable filter are updated using the identified resonance frequency to prevent mechanical damage caused by resonance and improve a servo tracking performance and reliability of data.

Abstract: A heat-assisted magnetic recorder for magnetically recording information onto a recording medium having a given recording coercive field includes an electron beam generator and a magnetic recording head. The electron beam generator directs an electron beam onto the recording medium in order to locally heat a portion of the recording medium such that the heated recording medium portion has a recording coercive field lower than the given recording coercive field. The magnetic recording head generates a magnetic recording field having an intensity greater than the recording coercive field of the heated recording medium portion in order to magnetically record information onto the heated recording medium portion. The electron beam generator includes a plurality of carbon nanotubes (CNTs) embedded in nanoholes of an anodic alumina template for generating the electron beam. A heat-assisted magnetic recording method is associated with the heat-assisted magnetic recorder.

Abstract: Magneto-resistive (MR) head pre-amplifiers for single polarity power supply applications are presented. An exemplary pre-amplifier includes a bias network coupled to first and second input terminals of the pre-amplifier, the input terminals for receiving signals corresponding to variations in magnetic fields from an MR head. At least one gain stage having first and second input terminals and first and second output terminals for amplifying the received signals is included. A pair of coupling capacitors, each capacitor being connected between a respective input terminal of the pre-amplifier and a corresponding respective input terminal of the at least one gain stage, are further included in the pre-amplifier design. Finally, the exemplary pre-amplifier includes a pair of feedback capacitors, each capacitor being connected between respective input and output terminals of the at least one gain stage. The pre-amplifier is powered by a single polarity power supply.

Abstract: In one example, a dual source tracking servo system includes a head assembly having a data transducer, a primary position detector for sensing the position of a magnetically stored data track, and a secondary position detector for sensing the position of a fixed reference associated with a magnetic storage medium. A controller is configured for adjusting the position of the head assembly in response to a weighted average of the sensed position of the magnetically stored data track and the fixed reference, wherein the position of the magnetically stored data track is weighted more than the position of the fixed reference. The primary position detector may include one or more dedicated servo read elements associated with the head assembly and the secondary position detector may include a magnetic or optical sensor. The fixed reference may include a tape edge or servo track.

Abstract: A system and method for processing track identifier errors to mitigate head instability in data storage devices is disclosed. The system and method includes computing a track id differential between an expected track id and a received track id, encoding the expected track id and the received track id, initiating a first action if the track id differential exceeds a pre-determined threshold and the encoded expected track id varies from the encoded received track id by a pre-configured number of bits, and initiating a second action if the track id differential does not exceed the pre-determined threshold or the encoded expected track id does not vary from the encoded received track id by a pre-configured number of bits.

Abstract: In a precompensation circuit for magnetic recording of data signals, a clock produces clock signals at a predetermined rate to clock the recording of the data signals. A clock delay generator generates clock delay data relative to the generated clock signals for successive data signals to be recorded. The clock delay data for each data signal is formed according to the states of a set of adjacent data signals. n>1 programmable clock delay units operate sequentially to control the recording times of the successive data signals. Each clock delay unit receives the clock delay data for one data signal in each sequence of n successive data signals and determines recording time of the one data signal according to the clock delay data for the one data signal in the sequence.

Abstract: A hard disk drive and magnetic medium including a servo area, a data area divided into a plurality of sector blocks and at least one micro-servo area disposed between two sector blocks. There may be a micro-servo area immediately preceding each of the plurality of sector blocks. The micro-servo areas include an address mark and a track parity check code that allow the detection of an external shock that causes the recording (write) head to skip to an adjacent track in the hard disk medium. The micro-servo area is smaller than the servo areas, and various numbers of different track parity check codes can be used for different resolution of shock detection. An acceleration sensor may also be provided to detect larger external shocks. By detecting various external shocks with improved accuracy, and aborting the recording operation of data if an external shock is detected, the corruption of data in adjacent tracks is substantially reduced to improve disk drive performance.