Abstract: A circuit to detect pin layer reversal including an input circuit to receive an input signal having a first portion to indicate a pin layer reversal and having a second portion to indicate a servo sync mark, a first servo sync mark detector for detecting a positive servo sync mark from the input signal, a second servo sync mark detector for detecting a negative servo sync mark from the input signal, and a circuit responsive to the positive servo sync mark and the negative servo sync mark to generate a signal to indicate if the servo sync mark has been reversed and to generate a signal to indicate the pin layer reversal.

Abstract: A magnetic transfer wherein the exchange of master mediums is made easy to perform is provided, whereby the operational efficiency and transfer efficiency are improved, leading to an overall improvement in productivity in the manufacture of preformatted slave mediums. A master fixing base for determining and supporting the position of a master medium, which bears transfer data, and a conjoining apparatus for conjoining the master medium and the slave medium that is to receive the transfer therefrom are provided. The master medium is exchanged along with the master fixing base. It is preferable that a cleaning means be provided.

Abstract: A method of measuring fly height of a read/write head to form a fly height profile for use in measuring fly height of the read/write head relative to a disc of a disc drive. A fixed source write signal is applied to an inductive element of the read/write head, generating a magnetic flux field with a stray magnetic flux field portion. A magnetoresistive element of the read/write head couples with the magnetic flux field producing an initial field strength signal. As the disc rotates, the read/write head flies there above decreasing the density of the stray magnetic flux field portion thereby decreasing the amplitude of the field strength signal. The decreasing amplitude of the field strength signal is calibrated to a predetermined operating fly height profile to correlate fly height of the read/write head to the decreasing amplitude of the field strength field, which forms the fly height profile.

Abstract: A disk drive is disclosed comprising a plurality of disk surfaces and a plurality of respective heads actuated radially over the disk surfaces. Each disk surface comprises a plurality of tracks, each track comprising a plurality of data sectors and a plurality of embedded servo sectors, each embedded servo sector comprising a servo sync mark for synchronizing to the embedded servo sector. When the disk drive switches heads, a detection window for detecting the servo sync mark is opened early. An asynchronous gain control algorithm prevents a gain control system from diverging while reading an area of the disk surface preceding the servo sync mark, and a synchronous gain control algorithm maintains a proper gain of the read signal while reading the servo sync mark.

Abstract: A voltage-mode boosting write driver circuit (40) having a pair of voltage boosting PMOS transistor sets (44, 46) coupled to a high current H-switch (42). One set (44) of the boosting PMOS transistors correspondingly pulls output pin HY high, while the other transistor set (46) correspondingly pulls output pin HX high and the other output pin HY low thereby significantly improving the head voltage swing, and also achieving a faster slew rate. Moreover, resistors (R3, R4) of the H-switch are both matched to each other and impedance matched to a flex cable (T0) interconnection impedance, which interconnection is coupled to the thin film head, to thereby eliminate signal reflection such that the write current (Iw) settles quickly with minimum ringing to achieve a high data rate. Moreover, less power dissipation and smaller number of devices used are achieved by making use of existing transient currents of the pre-driver emitter follower stage.

Abstract: A magnetic recording system containing magnetic recording media with separate data and servo magnetic layers is disclosed. A servo magnetic layer resides usually below the data layer and has higher coercivity than that of the data layer. Interference between the data and servo signals is minimized by recording the servo patterns perpendicular or transverse direction with respect to the orientation of data bits. In addition, servo patterns are selected so that no interference with the data is generated by the servo pattern when the reader is in the middle of data tracks. Tracking error signals are approximately linear with track misregistration around the middle of data tracks. Finally, interference between the data and servo signals is further reduced by electronic processing. Continuous servo signals permit increased track densities with a single actuator and very high track densities with dual microactuator-actuator system.

Abstract: In the magnetic transferring method for magnetically transferring an information signal such as a servo signal from the master medium to the slave medium, when magnetic transfer is performed by bringing a master medium and a slave medium into close contact with each other, the master medium bearing an information signal and the slave medium having a lubricating layer formed on the surface of its recording plane during use, and applying a transfer magnetic field, the magnetic transfer is performed by bringing the slave medium before the formation of the lubricating layer and the master medium into close contact with each other. Thus, the separation of the slave medium from the master medium after the magnetic transfer is facilitated, and the adsorption of dust on the slave medium is prevented.

Abstract: An information storage device which stores information in recording areas generated by dividing a track is provided, wherein servo information is configured, the information storage device including: a recording area setting part which divides a storage medium into predetermined recording areas; an error detecting part which detects an error in the servo information. When the error detecting part detects an error in the servo information, recording areas spanning from a recording area including the servo information having the error to a recording area including next servo information are replaced by other recording areas, wherein the servo error information is managed and recording area setting is restarted.

Abstract: A variable gain amplifier to output a differential output signal includes an input circuit to input a differential input signal, a buffer circuit to buffer the differential output signal to a common mode voltage, a compensation circuit to compensate the differential output signal to prevent variation in the differential output signal, and a comparison circuit to compare the common mode voltage to a predetermined voltage and to adjust the common mode voltage to equal the predetermined voltage.

Abstract: Arm electronics (AE) suitable for use in a disk drive are disclosed. The AE has write circuitry configured to operate the AE in a write mode during which a write mode supply current is drawn, and read circuitry configured to operate the AE in a read mode during which a read mode supply current is drawn. The AE uses a decaying current pulse generator that generates a decaying current pulse at the beginning of each write-to-read mode transition. The decaying current pulse has an initial value that is equal to the difference between the write mode supply current and the read mode supply current. This controlled load forces the AE to draw a gradually decreasing supply current for each write-to-read mode transition such that supply voltage transients (otherwise present due to parasitics in cabling between the AE and power supply) are reduced. Thus, the undesirable effects of such transients in the read circuitry are reduced so that write-to-read mode recovery times can be shortened.

Abstract: Partial information such as the beginning data of each of chapters is read from a CD and written in a HDD 10 at a higher speed than that in a normal reproduction while the normal reproduction is carried out using a buffer memory 8. After the chapters relative to all CDs have been written in the HDD 10, reproduction is carried out in switching between the information remaining in the HDD 10 and the information included in the CD. This configuration makes it unnecessary to record the information beforehand, and permits an unreproduciable blank in reproduction to be filled with audio information during track search or CD change while the reproduction is carried out normally.

Abstract: Disclosed is a digital VFO device which comprises a plurality of VFO circuits 12 and 14; synchronous counters 12a and 14a installed in each VFO circuits 12 and 14; and an adjusting circuit 110 selecting one of the VFO circuits 12 and 14 based on signals 113 and 114 representing the peak shift state of an input data 11 output from each VFO circuits. Correcting instruction signals 16 and 17 are generated to correct the synchronous counter of the other VFO circuits by substituting the counter value of the synchronous counter of the VFO circuit selected by the adjusting circuit 110 for the synchronous counter of the other VFO circuits.

Abstract: A differential amplifier circuit for amplifying an input signal and for providing an output signal representative of the input signal includes first and second amplifier circuits, and first and second coupling circuits. The first and second amplifier circuits each include first and second transistors, a resistor, and a current generator. The first coupling circuit includes a transistor, a capacitor, and a current generator, and couples a first input signal node to the first transistor of the second amplifier circuit. The second coupling circuit includes a transistor, a capacitor, and a current generator, and couples a second input signal node to the first transistor of the first amplifier circuit.

Abstract: A master information carrier for magnetic transfer to an in-plane magnetic recording medium includes a base sheet having an irregularity pattern representing information to be transferred to an in-plane magnetic recording medium and a magnetic layer formed along the irregularity pattern. The thickness da1 of the magnetic layer on the upper surface of a protruding portion of the irregularity pattern and the thickness da2 of the magnetic layer on each of the side surfaces of the protruding portion satisfy the following condition, 0.05<da2/da1≦1.3.

Abstract: A signal from a storage medium is processed in a data channel to form digital data. An amplifier and a sampler convert the storage medium signal into a timed sample sequence. A first equalizer and adjuster operates to equalize the timed sample sequence and to adjust the gain of the amplifier and timing of the sampler in a preamble segment of the signal. A second equalizer and adjuster circuit to equalize the timed sample sequence for detection and to adjust the gain of the amplifier and the timing of the sampler operates in a user data segment of the signal. An FIR equalizing filter in the second equalizer and adjuster circuit is controlled by a set of parameters to accurately equalize a large range of waveforms in the user data segment of the signal and an FIR equalizing filter in the first equalizer and adjuster circuit is controlled by a smaller set of related set of parameters adapted to accommodate rapid adjustment during synchronization in the preamble segment of the signal.

Abstract: A method and an apparatus for reducing position error signal in a disk drive, which has an actuator and a magnetic medium, write the servo tracks with a servo track writer using a varying increment. The servo tracks are written after the servo track writer incrementally moves the actuator by a non-constant amount. The non-constant incrementing enables a servo track writing operation to write servo tracks that are at least as wide near the outer circumference as they are near the zero skew position or near the inner circumference.

Abstract: A disk drive comprising a programmable inverting voltage regulator (PIVR) for generating an inverted voltage supply applied to a preamp is disclosed. The PIVR is programmably configured relative to the disk drive's mode of operation, including a read mode and a write mode.

Abstract: A disk driver writer precompensation system modulates the write current waveform based on a pattern of data bits magnetically recorded on a medium in order to adjust the timing of magnetic transitions recorded on the medium.

Abstract: A circuit controls the gain of an amplifier that amplifies an information signal. The circuit includes a buffer that stores two samples of the amplified information signal, and includes a gain-determination circuit coupled to the buffer. The gain-determination circuit generates a gain adjustment that is based on the two samples and that causes the amplifier to shift 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 disc drive includes a base and a disc rotatably attached to the base. The disc has an inner diameter and an outer diameter and a plurality of tracks. Information is written on the plurality of tracks. The plurality of tracks are written at a variable track pitch. The tracks positioned near the outer diameter are wider in pitch than the tracks positioned near the inner diameter. The plurality of tracks further include a first group of tracks written at a first track pitch, and a second group of tracks written at a second track pitch. The track pitch of each of the first group and the second group of tracks is selected such that the percentage of track misregistration for each group will be substantially the same. This method provides a means to increase storage capacity for a predetermined track misregistration budget.