Abstract: A magnetic read control apparatus magnetically reads information stored in a magnetic stripe of a medium by varying a relative carrying velocity between a velocity at which the magnetic head is carried in a predetermined direction and a velocity at which the medium is carried when a read error occurs in the information stored in the magnetic stripe of the medium.

Abstract: The invention includes operating a merged read/write head in a disk drive by determining both the maximum read bias current and maximum write current, based upon the measured read resistance of the read mechanism and the write current in use with the write mechanism. Both the read mechanism and write mechanism are near each other in the merged read/write head.

Abstract: A circuit controls the gain of an amplifier that amplifies an information signal. The circuit includes a buffer for storing first and second samples of the amplified information signal, and a gain-determination circuit coupled to the buffer. The gain-determination circuit generates a gain adjustment based on the sum of the first and second samples, the gain adjustment causing the amplifier to change the amplitude of the amplified information signal to or toward a predetermined amplitude. Such a circuit can provide an initial, coarse gain adjustment to a read-signal amplifier in a disk-drive read channel. Compared to prior read channels, this initial adjustment promotes faster settling of the amplifier gain at the beginning of a data sector. This faster settling allows the data sector to have a shorter preamble, and thus allows the disk to have a higher data-storage density.

Abstract: A procedure for reading data stored on a data storage disc in a disc drive is disclosed. The procedure involves reading data from one or more sectors on the data storage disc after an error occurred while initially reading the sector(s) pursuant to a read command issued by a host computer. During the initial read, the procedure logs information pertaining to the sector(s) on the disc where an error occurred. The logged information is then used during the procedure to retrieve data from the sector(s) in a single revolution of the disc. The procedure uses a skip mask, a vector buffer management list and a data throttling mechanism to administer a transfer of data from a disc to a host computer via a data buffer.

Abstract: The master information recording apparatus 100 includes a master information carrier, a master information carrier facing member, and a magnetic field applying member. A ferromagnetic thin film pattern formed on the surface of the master information carrier includes not less than two kinds of different patterns each having a different pattern angle showing an angle with respect to the direction of the relative movement between a magnetic head and a rotating magnetic recording medium. The magnetic field applying unit applies a magnetic field along the direction, which is perpendicular to the direction shown by an angle that is smaller than the pattern angle of the maximum pattern and larger than the minimum pattern angle of the pattern among the not less than two kinds of patterns.

Abstract: A data recording system for providing tamper proof recording has a housing; means to receive power to the system; an input port; at least one recording device; at least one storage device; a single cover with a locking means; a handling means to receive the storage devices following recording, stamp protective bags with indicia, seal the storage devices in the bags, and dispense the bags containing the storage devices through an output receptacle; an open button to unlock the cover only when no storage devices are in the system; input code keys and display for stamping indicia on the bags; a start key to lock the cover and activate recording; an off/eject key to stop the recording process and transfer the storage devices to the handling means.

Abstract: An apparatus and associated method for detecting head collision with disc media, or other matter, during a write operation is disclosed. The method and apparatus generally monitor the resistance of an MR element on the head in order to detect a temperature increases indicative of a head collision. The resistance can be compared to a pre-selected threshold to generate an output indicative of head collision.

Abstract: An unsafe detection circuit for detecting a kickback signal including an input circuit for inputting a kickback signal, a circuit for detecting the presence or absence of said kickback signal, and a fault detection circuit to respond to said presence or absence of said kickback signal to provide an indication of a fault.

Abstract: A magnetic write control apparatus transports a medium having a magnetic stripe, until the magnetic stripe reaches a magnetic write position. The apparatus moves a magnetic head and the medium relative to each other, thereby to perform magnetic writing on the magnetic stripe. The magnetic head magnetically writes prescribed data on the magnetic stripe, asynchronously with the relative motion of the magnetic head and the medium.

Abstract: A method and apparatus for handling end of data processing in a data storage device. The method includes receiving a plurality of user data bits at a write channel. The method further includes appending primary padding bits to user data bits if the plurality of user data bits is less than a multiple of an input block length of an encoder in the write channel and encoding the plurality of user data bits and any primary padding bits into a plurality of encoded data bytes. Additionally, the method includes appending an end of data marker to an end of the plurality of encoded data bytes, wherein the end of data marker has a length of no more than one byte, and writing the plurality of encoded data bytes and the end of data marker to the data store.

Abstract: A magnetic transfer apparatus capable of enhancing the quality of a transfer signal by improving close contact property between master and slave media in magnetic transfer carried out to magnetically transfer an information signal such as a servo signal from the master medium to the slave medium. In the magnetic transfer specifically carried out by applying a transfer magnetic field in a close contact state of the master medium bearing information and the slave medium, the master and slave media are closely contacted with each other in a state where the backside of the master medium is adsorbed and held on the flat adsorbing surface of an adsorbing member to heighten the flatness of the master medium. In the case of one-surface transfer, preferably, an elastic body is closely contacted with the surface opposite to the master medium on the slave medium.

Abstract: In a magnetic recording playback device, since minimum redundant bytes required for satisfying a target error rate are added, the addition of more redundant bytes than are necessary is reduced, whereby overwrite of the drive due to the redundant bytes is reduced. The size of redundant bytes to be added in a formatter block is varied according to the defect condition or electric characteristic of a medium on which data are to be written, or the electric characteristics of a write head for writing the data and an MR head for reproducing the written data.

Abstract: A guardband portion is written on a disc surface in a disc drive. A predetermined data pattern is written on at least one data track adjacent to the guardband portion. A predetermined guardband pattern is written at a plurality of different guardband frequencies in the guardband portion. For each guardband frequency, at least one performance criterion is measured for the data track. A desired guardband pattern is written on the guardband portion of the disc surface at a guardband frequency chosen based on the measured performance criterion.

Abstract: An apparatus, method and computer program product for a hard disk drive defect detection system. In one embodiment, a method of detecting defects on the surface of a disk having a plurality of tracks is recited. The method comprises reading, one or more times, the servo bits for a plurality of sectors and determining a burst measure for at least one sector, where the burst measure is a function of the burst signals for the sector. This method further comprises determining a reference value, where the reference value is a function of the burst signals of the plurality of sectors, and comparing the burst measure of at least one sector to the reference value to identify a potential defect. In one embodiment, a sector is mapped as defective where its burst measure differs from the reference value by at least 5 percent.

Abstract: A system, method and computer program product provide an annealing process for setting a magnetization condition of a read head. An amount of heat for stabilizing magnetization condition of a read head is calculated. A width and amplitude of a voltage pulse that generates the calculated amount of heat in the read head are calculated. A voltage pulse of the calculated width and amplitude is applied to the read head for generating Joule heating in the read head. The width of the voltage pulse is less than one second.

Abstract: A magnetic transcription device for transcribing information signals of a master information carrier in a magnetic recording medium by applying a magnetic field generated by magnetic field generating means to a contact body obtained by contacting the master information carrier having a base on which ferromagnetic bodies corresponding to the information signals are formed with a magnetic recording medium having a ferromagnetic layer, wherein the magnetic recording medium includes driving means for adjusting a distance between the magnetic field generating means and the contact body while rotating the magnetic field generating means relative to the contact body.

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 the base and a device for moving the actuator assembly. The actuator assembly includes an arm carrying a transducer head in a transducing relationship with respect to the disc. The disc drive further includes a servo circuitry and a controller for controlling movement of the actuator assembly during a track follow and a track seek. Piezoelectric transducers are attached to the actuator assembly for non-intrusive measurement of stiction and friction forces developed between the transducer head and the disc during a disc drive spin-up.

Abstract: A scanner (3-85, 8-85, 9-85) for use in a helical scan magnetic transducing apparatus has a periphery upon which plural read tranducing elements (3-82) and plural write transducing elements (3-80) are mounted non-symmetrically. The plural write transducing elements are physically situated on the periphery of the scanner in M number of local groups (3-81), wherein the plural read transducing elements are physically situated on the periphery of the scanner in N number of local moveable groups (3-831, 3-832), and wherein M<N. Each of the moveable groups has a separate actuator (89) for adjusting position of the group.

Abstract: It is generally believed that, the more pure the servo pattern timing reference, the better. A system writes a servo clock track on a disc in a disc drive. The clock track is written on the disc and the servo system is configured to reduce a splice error in a timing signal based on the clock track. The system is also configured to reduce phase-locked oscillator (PLO) jitter in the timing signal. In one embodiment, the splice error and PLO jitter are both measured using a single phase measurement circuit.

Abstract: A circuit includes a buffer for receiving and storing two samples of a signal, and a phase calculation circuit for calculating from the samples a phase difference between one of the samples and a predetermined point of the signal. Such a circuit can be used to decrease the alignment-acquisition time of a digital timing-recovery loop, and thus allows a shortening of the sector preambles and a corresponding increase in the data-storage density of a disk. In one application, the circuit determines an initial phase difference between a disk-drive read signal and a read-signal sample clock. The digital timing-recovery loop uses this phase difference to provide an initial coarse alignment between the read signal and the sample clock. By providing an initial coarse alignment, the recovery loop reduces the overall alignment-acquisition time.