Abstract: A head actuator assembly of a disk device has a suspension which supports a head, an arm which supports the suspension and is rotatably supported by a bearing portion, signal wires which extend on the suspension and the arm and are connected electrically to the head, and a board unit. In manufacture, the signal wires are mounted on the suspension and the arm, and a connecting end portion of the board unit is connected to the signal wires mounted on the suspension and the arm. Thereafter, the head is mounted on the suspension and connected electrically to the signal wires.

Abstract: A head actuator assembly of a disk device has a suspension which supports a head, an arm which supports the suspension and is rotatably supported by a bearing portion, signal wires which extend on the suspension and the arm and are connected electrically to the head, and a board unit. In manufacture, the signal wires are mounted on the suspension and the arm, and a connecting end portion of the board unit is connected to the signal wires mounted on the suspension and the arm. Thereafter, the head is mounted on the suspension and connected electrically to the signal wires.

Abstract: According to one embodiment, a recording medium, a drive motor which supports and rotates the recording medium, heads, and a head actuator are arranged in a case of a disk apparatus. The drive motor includes a rotor rotatably supported by a fluid bearing and a stator arranged at an outer periphery of the rotor in a circumferential direction and having a plurality of magnetic poles confronting with magnetic poles of the rotor. The stator includes a removed portion which is located on a moving path of the heads and in which magnetic poles are removed in a range corresponding to 25% or less of the entire angle of 360° of the stator in the circumferential direction, a plurality of stator magnetic poles arranged at intervals in the circumferential direction except the removed portion, and a magnet attraction plate arranged in the removed portion and opposed to the rotor.

Abstract: According to one embodiment, a magnetic disc device includes a disk medium to magnetically record data and a nonvolatile memory storing a program for manufacture thereon and capable of rewriting data. After completing running of the program for manufacture, a microprocessor uses the data recording area on the nonvolatile memory as a data recording area of the magnetic disk device together with the data recording area of the disk medium.

Abstract: A head actuator assembly of a disk device has a suspension which supports a head, an arm which supports the suspension and is rotatably supported by a bearing portion, signal wires which extend on the suspension and the arm and are connected electrically to the head, and a board unit. In manufacture, the signal wires are mounted on the suspension and the arm, and a connecting end portion of the board unit is connected to the signal wires mounted on the suspension and the arm. Thereafter, the head is mounted on the suspension and connected electrically to the signal wires.

Abstract: A disk drive including a magnetic disk having a plurality of concentric tracks formed thereon and a plurality of blocks each having data recorded on the track and a block address, a buffer memory, divided into plural segments, for storing data retrieved from the disk in each of the buffer memory segments, and buffer memory controller for controlling the buffer memory. The buffer memory controller includes a directory storage memory for storing buffer memory address information in directory segments corresponding to the buffer memory segments, a replacement control information storage memory for storing in each directory segment information relating to a history of use of data for each buffer memory segment.

Abstract: A magnetic disk apparatus designed to obtain data on the position of heads and the rate of movement thereof by extracting the peak values of servo signals corresponding to the positions of a plurality of cylinders set to rotatable disks as analog data on the basis of predetermined timing signals and converting the peak values thus extracted into digital data.

Abstract: A write compensator for a magnetic disk apparatus includes a flip-flop for latching write compensation information using not a recording data format conversion reference clock but converted recording data. The flip-flop latches the write compensation information until the next recording data is input. The recording data is write-compensated on the basis of the latched write compensation information.

Abstract: A speed control apparatus includes a speed signal-holding circuit. Even if a discrete portion occurs in the position signal, i.e., if an abnormal signal component is included in the speed signal derived from position signal differentiation, the speed signal held by the holding circuit is output to prevent erroneous operation caused by the abnormal signal. In a magnetic disk apparatus incorporating the speed control apparatus, the magnetic head is driven before a seek instruction is completely input, and the position signal phases are switched at proper timings, thereby reliably performing both speed and positioning control operations of the magnetic head, at high speed.

Abstract: A microprocessor is provided for calculating, based on the target track address set in the target address register, the target velocity in the seek operation of the magnetic head up to the target track. When the target velocity of the magnetic head is comparatively large, the microprocessor increases the revision interval of the target velocity, based on a prestored program, such that it is larger than the normal revision interval. The microprocessor varies the target velocity revision interval by a pulse signal output from a circuit which divides the track pulse by 1/2, for example.

Abstract: A controlling apparatus for achieving velocity control in the course of a seeking operation of the magnetic head includes an intended address register for storing intended track addresses. A microprocessor calculates the intended moving distance of the head on the basis of an intended track address applied from the intended address register and track pulses applied from a track detector circuit every time the head crosses a track on the magnetic disk. On the other hand, previously stored in a memory are plural kinds of velocity tables consisting of plural kinds of intended velocity data which correspond to the intended moving distance of the head. The microprocessor reads and sets from the memory appropriate intended velocity data which corresponds to the intended and calculated moving distance of the head. The head is moved by a carriage and performs its seeking operation at an appropriate velocity on the basis of the intended velocity data set by the microprocessor.

Abstract: A disk control circuit for a magnetic disk apparatus including a magnetic disk for storing data, a carriage for supporting a first magnetic head for reading data and a second magnetic head for reading servo data while undergoing radial movement with respect to the disc, a motor for driving the carriage, a motor driving circuit for driving the motor, a converter circuit for converting servo data to a position signal, to a speed signal, and to a track pulse, a processor for generating target speed information and track offset information, a servo control register for storing the track speed information and the track offset information, a digital to analog convertor for converting the track information to an analog signal, signal selector means for selectively generating motor control signals based on predetermined combinations of the speed signal, the position signal and the analog signal produced by the digital to analog converter, and a motor drive controller for generating and applying motor drive control si

Abstract: A rotation control device for a magnetic disk drive apparatus, which provides electrical regenerative braking of the apparatus prior to and continuously with actuation of an electro-mechanical braking system, once power is cut off to the apparatus. The use of electrical regenerative braking minimizes wear on the mechanical braking components and reduces maintenance on the apparatus. The use of electro-mechanical braking at low speeds assures reliable continuous braking when the electrical regenerative braking becomes relatively ineffective at low speeds.