Abstract: One circuit generates a constant positive potential, another circuit generates a constant negative potential. The positive potential and the negative potential are applied to a magneto-resistive head that reads data from and writes data to a magnetic disk. The positive potential is generated using a positive voltage source, an operational amplifier, and an NMOS transistor. The negative potential is generated using a negative voltage source, an operational amplifier, and a PMOS transistor.

Abstract: A method of erasing a disk by applying a direct current to a transducer while the transducer is moved in a selected manner relative to the rotating disk. The rotating disk in conjunction with the erasing transducer moving in a first direction in a substantially continuous and smooth manner yields a helical shaped erased path on the disk. Such helical erasure of the disk is faster than conventional erasure method that erases the disk by erasing in concentric circular paths. To erase in circular paths, the transducer needs to be positioned on that circular path, and positioning of the transducer involves a repositioning time that can be significant. The helical erasure method substantially eliminates the repositioning time since the path of the transducer is substantially continuous and smooth. The reduction in erasure time by use of helical erasure method is substantial when compared to the total erasure time.

Abstract: A write driver for use with a magnetic recording head includes a photoconductive switch that is positioned adjacent a magnetic recording head for switching current waveforms. Both light and a DC voltage are applied to the photoconductive switch to switch the applied current waveforms. The write driver further includes means for writing to a storage medium in response to current waveforms switched by the photoconductive switch. The write driver may also include a suspension that supports at least one photoconductive switch, DC conductors for supplying a DC voltage, means for supplying light, and recording head means for writing to a storage medium.

Abstract: The present invention decreases the number of repositions during read back by making use of multiple read elements associated with each data track. Each of a plurality of sets of read electronics receives the read signal from either one or the other of the two read elements associated with each data track and converts the received read signal into read data. For each data track, control logic selects one of the two read elements as a source for output data. In response to a determination that a read error has occurred, the control logic selects the other of the two read elements as the source for output data. For each data track, one read element is offset relative to the other read element in an offset direction normal to the tape direction.

Abstract: A method of tuning a bias parameter for a magnetoresistive head in a data storage system includes the step of identifying, from multiple possible bias parameter values, a smallest bias parameter value for the magnetoresistive head which both maintains a bit error rate above a predetermined threshold bit error rate, and which satisfies a second criteria. The method then includes the step of setting an operational bias parameter value for the magnetoresistive head to the identified smallest bias parameter value. Also disclosed are data storage systems, or controllers which are connectable to or included with data storage systems, configured to implement the methods.

Abstract: In a positioning control device for a two-stage actuator having a coarse-movement actuator and a fine-movement actuator, a notch filter having a cutoff frequency fn is provided to a coarse-movement control loop, and the fine-movement actuator is driven by a sine wave of the frequency fn. At the frequency fn, a head position signal becomes identical with an output signal of the fine-movement actuator, by which the gain of the fine-movement actuator can be estimated by an adaptive identification unit with high accuracy based on the control input to the fine-movement actuator and the head position signal.

Abstract: A magnetic recording apparatus provides improved resolution and S/N without adversely affecting thermal stability. An angle formed by the direction of easy magnetization of a recording layer and the direction normal to a magnetic recording medium is in the range between 5° and 55°, the easy magnetization direction is from a back surface of the recording layer toward a front surface thereof, and when a recording track direction is from the upstream of the direction of transportation of the medium toward the downstream thereof, an angle formed by the direction of a projection of the easy magnetization direction on the medium plane and the recording track direction is in the range between 0° and 70°.

Abstract: The occurrence frequency of read error occurring when the data on one disk is read by a read unit is compared with that when the data on another disk is read by the read unit and the evaluation result of relatively evaluating the disks is displayed on a display section as the ranking of the disks. Therefore, the user can easily and precisely determine the disk having a good affinity for the apparatus main unit.

Abstract: An encoding system and associated method protect against miscorrection due to parity sector correction in, for example, an on-drive RAID system. The system adds a parity cluster block, which itself is a complete, C3-protected cluster. Having the cluster level, C4 level correction, by parity sectors, checked and verified by C3 checks that have high reliability level, as well as the capability for checking consistency of a cluster block, even in the presence of “jami” errors, makes this possibility unlikely. A scrub algorithm avoids read-modify-write operations by deferring the completion of the C2 and C3-ckecks until the storage device is idle.

Abstract: An input signal is recorded in a recording tape ? by converting the input signal to a record signal through the modulation performed at the timing corresponding to the previously-specified number of tracks per division of signal by using input-signal converting means 1,2, 3, and 10 and then rotating a head cylinder 8 at a revolving speed lower than the revolving speed of the head cylinder 8 corresponding to the timing for modulation and corresponding to a recording rate adjusted by the recording-rate adjusting means 12 by using recording means 7, 8, 9, 10, and 11. Thereby, it is possible to make the configuration of a head cylinder same even for a system in which the number of tracks per division of signal differs due to the difference in compressibility.

Abstract: An information recording and reproducing apparatus having a high track density, a high recording density in each of the tracks, and a short seeking time. In a seeking operation, a control circuit performs a calculation required for the seeking operation and then sets, to (f=fs), a drive pulse frequency f for a tracking control to be supplied to a piezoelectric element based on the calculation result. A drive circuit outputs a drive pulse of the frequency f corresponding to the input drive pulse to an actuator, so that a recording and reproducing head is moved near a target track. In a following operation, the control circuit performs a calculation required for following operation and then sets, to (f=ft, wherein fs>ft), the drive pulse frequency f to be supplied to the piezoelectric element based on the calculation result.

Abstract: A dual mode write driver, such as in a tape or disk drive system, provides both a voltage mode of operation and a current mode of operation by combining the required topology in a write driver circuit. A logic control signal applied to an input to the dual mode write driver causes the circuit to configure for either mode. The write driver has a first PFET (P3) coupled to a first NFET (N1) at a first node connected through a resistor (R1) to a first side of a write head (L1) of the write driver, and a second PFET (P4) coupled to a second NFET (N2) at a second node connected through a resistor (R2) to a second side of the write head. A first voltage mode NFET device is turned on during the voltage mode to connect the sources of the first and second NFET devices to ground.

Abstract: A method and system for calibrating the write current of a current mode write driver having a first PFET coupled to a first NFET at a first node connected to a first side of a write head of the write driver, and a second PFET coupled to a second NFET at a second node connected to a second side of the write head. The write driver also defines an INODE where a source of the first NFET is coupled to a source of the second NFET, and the write driver is put in a state where all FET devices are in an off condition. A precision resistor R is connected from the NODE I/O pin of the write driver to a positive potential VDD I/O pin of the write driver, causing a current I1 to flow, where I1=V/R, and V is a voltage across the resistor.

Abstract: A magnetic transfer system includes magnetic recording medium stocker which holds a plurality of magnetic recording media, a magnetic transfer apparatus which magnetically transfers information represented by a magnetic layer on a master information carrier to the magnetic recording medium by applying a transfer magnetic field to the magnetic recording medium and the master information carrier with the magnetic recording medium and the master information carrier held in close contact with each other, and a conveyor which conveys the magnetic recording medium between the magnetic recording medium holding means and the magnetic transfer means. The magnetic recording medium holding stocker, the magnetic transfer apparatus and the conveyor are formed of material which contains substantially no chlorine, sulfur compound or nitric oxide at least at a part which is brought into contact with the magnetic recording medium.

Abstract: A modified disk drive that includes means for selectively and permanently disabling the write mode of the hard disk drive by the use of programmable read only memory (PROM) circuitry is provided. One method of use employs selectively blowing a PROM fuse in the arm electronics of the hard disk drive to prevent further writing to a respective disk surface in the hard disk drive. A second method of use employs selectively blowing a PROM fuse in processor-accessible memory, to prevent further writing to a section of logical block addresses (LBAs) corresponding to a respective set of data sectors in the hard disk drive.

Abstract: A digital information reproducing apparatus using rotary heads that reproduces digital information signals recorded on a magnetic tape using magneto resistive heads installed on a rotary drum. The apparatus includes, in the fixed side of the apparatus, a magnetic tape checking circuit that checks the type of the magnetic tape; and a control signal generation circuit that generates a control signal for controlling the gain of a reproduction amplifier circuit; and on the rotary drum, a decoder circuit that identifies the control signal transmitted from the control signal generation circuit. The control signal generation circuit generates the control signal based on a checking result given by the magnetic tape checking circuit, and the decoder circuit identifies the transmitted control signal to control the gain of the reproduction amplifier circuit.

Abstract: A method of operating a transducer includes heating a write element by passing a preheat electrical current through a conductive coil of the write element in a manner which produces a substantially zero magnetic flux. The method also includes writing data to a media after heating the write element by passing a write electrical current through the conductive coil in a manner in which produces a net magnetic flux.

Abstract: A magnetic head driving circuit includes a main driving circuit symmetrical with respect to a centered recording coil, and at least two pairs of adding circuits, each pair including a positive pulse adding circuit and a negative pulse superposed circuit symmetrical with respect to the centered coil. And, by reversing the direction of the magnetic head coil current, at least one of the adding circuits is made to operate and make it as a magnetic head driving circuit for adding a potential equal to or higher than the power supply, thereby to drive as a sub-driving circuit arranged symmetrically with respect to the centered coil, which promotes the reversal of the magnetic head coil current, and which drives stably with a central potential of the coil at about the disk potential.

Abstract: A master medium for magnetic transfer includes a substrate having a concave portion formed in its surface corresponding to a pattern of recorded information to be transferred; a first perpendicular ferromagnetic layer deposited in the concave portion; and a second perpendicular ferromagnetic layer layered on the substrate surface and the first perpendicular ferromagnetic layer surface. The substrate surface and the first perpendicular ferromagnetic layer surface are flattened to form a single flat surface. In the master medium for magnetic transfer, a magnetic field change in a direction parallel to the substrate surface at a magnetization boundary of the first perpendicular ferromagnetic layer is steep. Since the influence of the change of an external magnetic field is reduced, it is possible to perform accurate transfer from the master medium for magnetic transfer to a slave medium for magnetic recording.

Abstract: In a magnetic tape storage controlled by a server, three attributes, namely, “read/write,” “read only” and “protection” are provided for data to be written, and each magnetic tape is set to a mode in which multiple attributes can be handled or a mode in which only one attribute can be handled. By properly selecting an attribute and a mode, a backup state depending on the importance of data is achieved.