Abstract: A flexible magnetic disk drive is disclosed which operates under the control of a host system. A CMOS inverter is employed as a power saving switch, holding a file protect sensor energized only when the standard "drive select" signal from the host commands operation of the disk drive. Another CMOS inverter is provided for two disk capacity a sensors which provide signals indicative of the data storage capacity of the loaded disk cartridge. The disk capacity sensors are energized only when the drive select signal commands operation of the disk drive and when the standard "motor on" signal dictates rotation of a disk drive motor.

Abstract: A data transfer system of the type including a disk drive for selective use with flexible magnetic disk cartridges of first and second storage capacities (e.g. 1 MB and 4 MB), the first storage capacity being less than the second storage capacity, a host computer, and a controller for controlling the operation of the disk drive under the direction of the host computer. The controller is factory preprogrammed to discriminate between unformatted disk cartridges of the two different storage capacities as either of the two types of disk cartridges is loaded in the disk drive. The program is such that, in response to the first of a series of formatting commands at the first storage capacity from the host computer, the controller causes the disk drive to write track format for the second storage capacity on a preassigned track (e.g. inmost track) on the disk and then immediately to read the track format.

Abstract: An assembling position-adjusting mechanism of a magnetic disk apparatus able to adjust the azimuth, radial alignment, and index of a magnetic head by adjusting a position thereof during the assembling process of a spindle motor. A positioning head movable in a direction perpendicular to a top surface of a table is provided. A plurality of positioning pins are provided on the bottom of the positioning head. Moving mechanisms are provided in the positioning head so that the bottom surface of the positioning head is movable and rotatable parallel to the top surface of the table. Each positioning pin of the positioning head is inserted into a respective positioning hole of a motor assembly so as to move the motor assembly with a movement of the positioning head so that the spindle motor of the motor assembly is at an appropriate position relative to the magnetic head of the main body of the magnetic disk apparatus.

Abstract: A magnetic disk drive is disclosed which has a tunnel erase head assembly comprising a read/write head for writing and reading data on a magnetic disk, and a pair of tunnel erase heads for trimming a pair of opposite marginal edges of the record track being formed by the read/write head, with the consequent formation of spaces intervening between the record tracks. The spaces created on the same disk by different disk drives may be of one polarity of magnetization or the other, with the possibility of noise production due to an abrupt change in the polarity of magnetization as the read/write head scans any of the spaces as a result of mistracking. For the reduction of such noise the coil of the tunnel erase heads is connected to an erase current source via a circuit whereby the erase current is made to have a staircase or ramp rise and fall.

Abstract: A floppy disk drive is disclosed which is for use with a host system capable of connecting its own power supply to the disk drive when its operation is needed, and disconnecting the power supply from the disk drive when its operation is not needed. The disk drive includes a stepper motor for moving a data transducer from track to track on a rotating magnetic disk, and a track counter for ascertaining the radial position of the transducer on the disk by counting the stepping pulses fed from the host system to a stepper motor control circuit. In order to maintain the count of the track counter despite power suspension, the track counter is connected to a supply terminal of the disk drive via a reverse blocking diode, and a capacitor is connected between the diode and ground. The track counter is therefore fed from the capacitor when the disk drive is disconnected from the power supply of the host system.

Abstract: A head carriage apparatus includes a head carriage including a head being placed onto a disk for recording and reproducing information on the disk and having an extension and a connecting portion formed on the extension integrally with the head carriage, a lead-screw shaft having a lead screw in which a thread ridge and a thread groove are formed, the connecting portion being fitted in the thread groove of the lead screw, a drive part for driving and rotating the lead-screw shaft so that the head carriage is moved in a radial direction of the disk parallel to an axial direction of the lead-screw shaft, a guide shaft for guiding movement of the head carriage in a direction parallel to the radial direction of the disk, the head carriage being supported by the guide shaft at two supporting positions being located apart from each other in axial direction of the guide shaft, and a resilient part for pressing the lead-screw shaft in a direction facing the head carriage, the resilient part being fixed at one end ont

Abstract: A floppy disk drive controller has a control part which performs a plurality of kinds of controls by means of outputting control information appropriate to each kind of control, and a memory part in which information which selects a predetermined kind of control from among the plurality of kinds of controls is pre-stored, the control part outputting the control information corresponding to the predetermined kind of control which is selected based on the information from the memory part.

Abstract: A disk drive connected to a host computer compatible with a plurality of computer hardware types can automatically transmit one desired control signal to the host computer, the desired control signal corresponding to a computer hardware type which is being used for the host computer. The disk drive may use a signal transmitted from the host computer which represents a storage capacity of a disk used for the disk drive.

Abstract: A flexible magnetic disk drive is disclosed which has a stepper motor coupled to a data transducer via a steel belt motion translating mechanism for moving the transducer from track to track on the rotating disk in response to stepping pulses and a stepping direction signal from an external host system. In order to save power, the stepper motor is held deenergized while the disk drive motor is out of rotation, with the consequent possibility that the transducer may be displaced from the required track position on the disk while the stepper motor is held deenergized. Therefore, in order to always memorize the latest of the successive destination tracks commanded by the host system, a forward/backward counter is provided which counts the external stepping pulses in either direction depending upon the binary state of the external stepping direction signal.

Abstract: In order to drive the stepper motor of a floppy disk drive with practically constant current in the face of fluctuations in supply voltage fed from a host system, a power control pulse generator circuit is provided which produces a series of power control pulses having a duty ratio dependent upon fluctuating supply voltage. The power control pulses are used for interrupting the excitation of the stepper motor windings during track seek operation. The power control pulses are generated by first repeatedly counting clock pulses from the host system to a predetermined number to provide periodically varying digital data, then translating the digital data into a triangular wave having an amplitude dependent upon the supply voltage, and then comparing the triangular wave with a reference voltage.

Abstract: An optical recording/reproducing apparatus records an information signal on a rotary optical disk by irradiating an optical beam having an optical power such that an energy sufficient to cause recording of the information signal is incident to a unit area of the optical disk in a unit time while revolting to optical disk at a first predetermined speed, and plays back the information signal from the optical disk by irradiating the optical beam while revolving the optical disk with a second predetermined speed such that the energy incident to a unit area of the optical beam in a unit time at the time of playback does not cause recording on the optical disk.

Abstract: A tracking servo apparatus for performing a control so that a light beam is irradiated onto a predetermined track of an information recording surface of a disc shaped recording medium comprising an optical system for focusing the light beam on the information recording surface of the disc shaped recording medium, a holder for holding the optical system, tracking error detection circuit for detecting a tracking error of the light beam irradiated on the information recording surface with respect to the predetermined track by receiving a reflected light of the irradiated light beam that has been reflected from the information recording surface, and outputs an error signal in accordance with the tracking error, and a piezoelectric device which is connected to the holding means, and is deformed when supplied with an amplified voltage of the error signal so as to deflect the holder and thus moves the optical system so that the light beam is irradiated on to the predetermined track of the information recording surfa

Abstract: A magnetic disc apparatus comprises a single write/read magnetic head for carrying out write/read with respect to either one of a low-density magnetic disc and a high-density magnetic disc, and a cosine equalizer supplied with a read signal from the write/read magnetic head. The write/read magnetic head has a core gap length which is between 0.60 and 1.20 times a minimum field conversion length for high-density write by a write/read signal.

Abstract: An optical head apparatus applicable to an optical disc apparatus comprises, a case body having an open surface and a window through which an opto-electronic component can be positioned and housing optical components inside it, a lid being attachable and detachable with respect to the open surface of the case body, and a flexible printed circuit board having a base portion which is adhered to the lid and on which electronic components are mounted and a protruding portion protruding from the base portion and having an opto-electronic component fixed to the distal end portion of it, the opto-electronic component being electrically connected with an electronic circuit which is formed by the electronic components, the distal end portion of the protruding portion of the flexible printed circuit board being fixed to the case body so that the opto-electronic component is position to the window.

Abstract: A recording head of a magneto-optical disk apparatus for recording and/or erasing an information signal on and from a magneto-optical disk mounted on the apparatus comprises optical pickup device disposed at a first side of the magneto-optical disk for producing an optical beam such that the optical beam is focused on the first side of the magneto-optical disk, pickup feeding mechanism provided on a frame of the magneto-optical disk apparatus for moving the optical pickup device along a path extending in a radial direction of the disk, a stepping motor disposed at a second side of the magneto-optical disk, the stepping motor having a housing containing a rotor magnet and a stator winding surrounding the rotor magnet, the rotor magnet including a plurality of elongated magnetic parts magnetized to either one of the N-pole and S-pole and arranged with alternate polarity about a rotary axis of the stepping motor such that each of the elongated magnetic parts extends parallel to the rotary axis, the rotor magnet

Abstract: An optical recording and reproducing apparatus includes a controlling circuit for controlling a light intensity of a laser beam emitted by a laser diode. The controlling circuit sets the light intensity in a verifying mode at a level lower than those in data read and write modes. The verifying mode is a mode for verifying whether or not the recording or reproducing apparatus can operate correctly. The apparatus also comprises a verifying circuit for comparing the reproduced information signal obtained in the verifying mode with a reference information signal which corresponds to the information signal written into the optical disc.

Abstract: An optical assembly of an optical recording/reproducing apparatus for focusing an optical beam produced by a light source on a recording medium and for directing the optical beam reflected back from the recording medium to detectors comprises a first optical system including a first objective lens for focusing an optical beam on a first recording surface at a first side of a recording medium, a second optical system including a second objective lens for focusing the optical beam on a second recording surface at a second side of the recording medium, and an optical path switching means switched between a first and second states for selectively establishing an optical path connecting an optical processing unit including the light source and detectors to either one of the first and second optical subsystems.

Abstract: A magneto-optical recording system comprises a first optical system carried by a first focusing actuator disposed at a first side of a magneto-optical recording medium and second optical system carried by a second focusing actuator disposed at a second side of the magneto-optical recording medium. When recording an information signal on the first side of the magneto-optical recording medium by means of an optical beam focused by the first optical system, the second focusing actuator is supplied with a biasing current and produces a magnetic field for recording. When recording an information signal on the second side of the magneto-optical recording medium, the first focusing actuator is supplied with a biasing current and produces a second magnetic field for recording.

Abstract: A magnetic or optical disk apparatus featuring a circuit for generating a dual implication MOTOR STATUS signal in response to a MOTOR SPEED signal representative of the speed of rotation of a disk drive motor and to a MOTOR ON signal dictating the rotation and nonrotation of the disk drive motor. The MOTOR STATUS signal indicates: (1) the rotation of the disk drive motor at a desired normal speed, enabling data transfer between the disk and a head; and (2) the slowing down of the motor to a predetermined speed close to zero. The two implications of the MOTOR STATUS signal can be distinguished from each other by reference to the MOTOR ON signal. The first implication may be used to enable reading or writing of data on the disk, and the second implication for disk ejection and for opening a power switch or switches, among other purposes.

Abstract: A flexible magnetic disk drive has an index sensor which, during the rotation of the magnetic disk, generates a series of index pulses representative of the angular position of the magnetic disk. The index pulses are delivered to a host system only when a drive select signal supplied therefrom to the disk drive is in a prescribed state dictating the execution of reading or writing by that disk drive. Since the host system responds to the leading edges of the incoming index pulses for formatting the magnetic disk, any index pulse should be suppressed if the drive select signal assumes the prescribed state during the duration of that index pulse; otherwise, the leading edge of the index pulse would erroneously represents the angular position of the magnetic disk.