Abstract: In a coding method which does not restrict a run length of “1” while data is recorded/reproduced, there are such a drawback that when an error correction is carried out, a total number of error data to be corrected is increased, and also errors of not-detectable data are increased. While data is coded, a continuous number of “1” contained in a code word is limited, and then an error correction is carried out inside a coding/decoding process operation. Thus, a recording/reproducing apparatus having a small number of decoding errors is available.

Abstract: Demagnetizing magnetic media for recording data in a data storage device includes placing the magnetic media in a magnetic field at a first strength, and gradually reducing the magnetic field to a second strength to essentially eliminate net magnetization in the magnetic media.

Abstract: A recording target error rate is selected for one or more of data storage devices, and for each data storage device, a dither value is determined for each read/write head in the data storage device, wherein for each head, using a dither value for writing data, essentially provides the selected recording target error for all the heads.

Abstract: To enable alignment of a magnetic pattern of a pair of master disks and a magnetic recording medium, each of the master disks has at least a pair of alignment marks disposed outside the region of the magnetic pattern. The master disks can be optically transparent or semi-transparent. The master disks can be aligned while the alignment marks are externally observed.

Abstract: By bring a master carrier and a slave medium into close contact with uniform force when executing magnetic transfer by applying transfer magnetic field in the state that the master carrier and slave medium is in confronted close contact and received within a holder, inferiority of transfer such as omission of signals is prevented and quality of transfer signals is enhanced. The magnetic transfer apparatus executes magnetic transfer by applying transfer magnetic field by means of a magnetic field applying apparatus 5 after a master carrier 3, 4 bearing transfer information and a slave medium 2 to be transferred are brought into confronted close contact and received within a holder 10, wherein said holder 10 has a substantially circular shape and in particular, the circularity of holder is not less than 98%, wherein the flexural rigidity=Ed3/12 determined by Young's modulus E and thickness d of the holder is in the range of 0.

Abstract: By bring a master carrier and a slave medium into close contact with uniform force when executing magnetic transfer by applying transfer magnetic field in the state that the master carrier and slave medium is in confronted close contact and received within a holder, inferiority of transfer such as omission of signals is prevented and quality of transfer signals is enhanced. The magnetic transfer apparatus executes magnetic transfer by applying transfer magnetic field by means of a magnetic field applying apparatus 5 after a master carrier 3, 4 bearing transfer information and a slave medium 2 to be transferred are brought into confronted close contact and received within a holder 10, wherein said holder 10 has a substantially circular shape and in particular, the circularity of holder is not less than 98%, wherein the flexural rigidity=Ed3/12 determined by Young's modulus E and thickness d of the holder is in the range of 0.

Abstract: A disk erase apparatus for erasing information on one or more disks in a disk drive uses a high strength magnetic field to erase the disks while the disks are in the HDD assembly. The design of the head disk enclosure provides a reduced thickness in a localized region over the disks. This allows a narrower working magnetic gap of the HDD level disk erase apparatus. The localized region of the HDD may be a formed indentation on the top cover, elimination of flange, and reduced floor thickness of the HDD base.

Abstract: The invention is directed to patterned magnetic media for use in magnetic recording and data storage, and various encoding techniques that can be used to magnetically encode data on the patterned media. For example, a patterned magnetic recording medium can include a first set of surface variations and a second set of surface variations. The medium can be conditioned to magnetically expose the surface variations relative to areas between the respective surface variations. Detection of the surface variations in the first set can allow for synchronization of a magnetic drive to the medium. Following such synchronization, the magnetic drive can selectively apply magnetic fields to a second set of surface variations of the patterned magnetic medium to encode data on the patterned magnetic medium.

Abstract: A method and system for providing programmable self-testing of a data storage device comprises selecting one or more host programmable tests stored in memory in the data storage device by setting data in a first log in memory of the data storage device. Parameters for execution of the one or more host programmable tests are set by setting one or more values in a second log in memory of the data storage device. The one or more host programmable tests on the data storage device are then executed. Results of the one or more host programmable tests are stored in a third log in memory of the data storage device.

Abstract: A method and apparatus for generating an index location from a spin motor of a disk drive are disclosed. A disk drive includes a motor having a plurality of commutation states, wherein changes in commutation states are controlled by an FCOM signal having FCOM pulses. Ideally, when the motor is spinning at a constant speed, the time between FCOM pulses is constant. However, the inventor of the present invention has recognized that, in practice, the time between FCOM pulses, when measured more closely, is not constant due to mechanical tolerances in the motor. Accordingly, the inventor has determined that the non-constant times between FCOM pulses can be advantageously used to generate a spin motor index in a disk drive. Once obtained, the spin motor index may advantageously be used for a number of purposes.

Abstract: A disk drive has timing marks (TMs) on the disk, that are chosen to reduce the probability of misidentification of a TM in the presence of read errors. The disk drive searches for TMs within a fixed TM search window which extends past the TM on the disk. A TM preferably maximizes the post-shift sliding distance for m post-shifts of the TM pattern, where m corresponds to the TM search window boundary. In this manner, the probability of a misidentification of the TM due to a post-shift having a small distance from the TM pattern is reduced. The TM pattern also provides pre-shift error resistance.

Abstract: The present invention is a disc drive storage unit incorporating novel apparatus, data structure and method for uniquely identifying data written during each write command operation of the disc drive storage unit. The disc drive storage unit attaches unique write identification data (sequence data, time data, or both) to host computer data written during each sector write operation. The unique write identification data is attached through independent action of the disc drive storage unit. The unique write identification data is attached to the host computer data in such a way that the unique write identification data is transparent to the host computer. The data structure relates the host computer data to the unique write identification data. The method documents the manner in which unique identification data is attached to, and detached from, the host computer 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 slider having leading and trailing edges is configured to fly on an airbearing above a data storage disk rotating from the leading edge to the trailing edge. Read and write heads are mounted on the slider proximate the trailing edge. An auxiliary thermal sensor is mounted on the slider, but preferably nearer the leading edge. Forward placement of the sensor allows it to sense mechanical defects before they reach the heads, thereby permitting a write inhibit operation, for example. The sensor may also be used to detect airbearing modulation. Appropriate action may be taken when unacceptable airbearing modulation is detected, such as notifying the user and/or scrubbing the slider. The sensor is preferably wider than the heads. This allows, for example, an in-situ glide test to be performed faster using the sensor. An arm electronics module is preferably configured to permit concurrent operation of the sensor and heads.

Abstract: In a magnetic disk drive, a writing element and its surrounding area thermally expand due to the heat generated by a write head coil. The transient phenomenon of such thermal expansion may invoke the transient phenomenon of inadequate writing capacity, thereby causing a writing error at an early stage of a write operation. Control is provided which increases/decreases either or both the write current to be applied to a write head and the amount of its overshoot on an individual sector basis during a writing sequence.

Abstract: A recording/reproducing apparatus capable of switching over among a plurality of heads with high precision, wherein the apparatus is provided with: a recording/reproducing unit for recording/reproducing signals onto/from a recording medium with a plurality of heads; a generating unit for generating control data for controlling the recording/reproducing unit; and a transmitting unit for transmitting control data generated by the generating unit to the recording/reproducing unit, wherein priority is given in transmission to data for controlling the switching of the plurality of heads over other data.

Abstract: A correction mechanism for use in a data storage system that allows data to be read even if the recorded data has been phase shifted.

Abstract: A magnetic data embedding system (or disk servo writer) includes a stack with a master disk (3) and a plurality of magnetic disks (4) mounted on a shaft of a spindle motor (6), and a rotary positioner (11) which integrally holds one or more read-only heads (71 to 74) for reading the master disk and a plurality of groups of servo heads (101 to 104) and which simultaneously turns both of the kinds of heads. The groups of servo heads have access to the top and bottom sides of the magnetic disks. The servo heads are made carry out writing to the same (top or bottom) side of each of the disks in parallel, within assigned track ranges for the respective servo heads.

Abstract: A position information signal pattern is recorded into a recording medium. The position information signal pattern is configured by arranging graphics having a circular shape, a rectangular shape or the like surrounded by a certain closed curve as pattern elements on a plane, and arranging the pattern elements in circumferential and radial directions of a disc so that a phase and a head position establish a proportional relationship in two or more frequency components of a reproduced signal. Position signals of the two frequency components included in the reproduced signal from the position information signal pattern are obtained, and the two position signals are added up with a certain ratio so that a position signal without error is obtained.

Abstract: A perpendicular magnetic recording type of disk drive having function of removing a component of a shift in a base line of a reproducing signal is to be disclosed. The disk drive has a read channel including an extracting unit which extracts the component of the shift in the base line of the reproducing signal. The extracting unit includes low-pass filters, and parameters of a lower cut-off frequency of the low-pass filter are adjusted in read operation.