Abstract: A method for assembling and operating a fixed media hard disk drive using a disk or a stack of disks on which servo information is pre-written off the drive spindle. The disks are subsequently mounted on the drive spindle and a set of rotationally concentric “virtual tracks” for seeking and following in terms of said pre-written servo tracks are defined. The use of the concentric virtual tracks assures minimal actuator motion during drive operation and increases acceptable offtrack tolerances. The off-spindle, pre-writing of the servo information increases the efficiency of the assembly operation and reduces the clean room burden.

Abstract: The software system architecture supports a rotating media in the storage and retrieval of data, where the rotating media stores in data tracks of multiple sectors, through the use of a microcontroller for the execution of a control program that schedules plural control tasks temporally distributed for respective execution during the rotational period of a predetermined track and sector. The scheduling of the plural control tasks is synchronized with respect to data retrieved from the predetermined sector. The plural control tasks include a rotational control task for determining an adjustment to the spin speed of the rotating media, a track following task for determining an adjustment to the alignment of the read/write head with respect to the predetermined track and a sector timing task for determining the position of the read/write head with respect to the predetermined track.

Abstract: A hard disk drive system operates from a limited power source to provide for the storage of data on the surface of a rotating hard disk media. An embedded controller incorporates a data channel for transferring data with respect to a hard disk media. The controller includes first and second subsections and a power-down circuit for providing separately switchable power from the power source to the first and section subsections. The controller further includes a processor for controlling the power-down circuit. The processor nominally provides a low duty cycle control signal to the power-down circuit for switching the provision of power to the first subsection of the controller.

Abstract: A controller in a hard disk drive system for controlling the transfer of data and control signals between a plurality of host processors and the disk drive system. The disk drive system including storage media, at least one transducer for recording data on and retrieving data from the storage media and an actuator for moving the transducers with respect to the storage media. The controller includes a programmed first microprocessor operating under control of a first operating system stored in a first memory unit associated with the first microprocessor for controlling the recording of data on and the retrieval of data from the storage media, the controlling of the actuator to locate the transducer at and to maintain the transducer at a specified location with respect to the storage media.

Abstract: A hard disk drive system operates from a limited power source to provide for the storage of data on the surface of a rotating hard disk media. An embedded controller incorporates a data channel for transferring data with respect to a hard disk media. The controller includes first and second subsections and a power-down circuit for providing separately switchable power from the power source to the first and section subsections. The controller further includes a processor for controlling the power-down circuit. The processor nominally provides a low duty cycle control signal to the power-down circuit for switching the provision of power to the first subsection of the controller.

Abstract: An apparatus for a disk drive having at least one disk mounted in a housing having a controlled environment defined by the housing. Such a disk drive generally includes, within the controlled environment, one or more transducers for reading information from and writing information to the disk, and at least one actuator for selectively positioning the transducers with respect to the disks. Each actuator includes at least one magnet for providing a magnetic field and an actuator coil, mounted on the actuator, arranged so that a current in said coil creates a force to pivot the actuator. The apparatus comprises a magnet shield encasing each such magnet for preventing matter, generated during the decomposition of said magnet over a period of time, from interfering with the operation of the disk drive.

Abstract: A multi-layer data integrity system for use in a disk drive controller for ensuring the data integrity as data is transferred through the controller and written and fetched from the disk media. The disk drive controller is partitioned into an interface controller and a low level controller where the interface controller controls the transfer of data to and from the host processor and the low level controller controls the recording and reading from the disk media. The interface controller employs a first error encoding and detecting means for encoding the data as originally received from the host processor. The low level controller employs an error encoding and detecting means for encoding both the received data and the encoding data which was appended to the data received by the interface controller. The low level controller's error encoding and detecting means corrects errors detected in recovered data.

Abstract: A hard disk drive system operates from a limited power source to provide for the storage of data on the surface of a rotating hard disk media. An embedded controller incorporates a data channel for transferring data with respect to a hard disk media. The controller includes first and second subsections and a power-down circuit for providing separately switchable power from the power source to the first and section subsections. The controller further includes a processor for controlling the power-down circuit. The processor nominally provides a low duty cycle control signal to the power-down circuit for switching the provision of power to the first subsection of the controller.

Abstract: A quadrature based embedded servo control system is provided to realize a high track density, high-performance hard disk drive system. Each data sector includes a gray code field spanning the entire width of the data track and a quad-servo burst pattern having first, second, third, and fourth servo burst fields distributed along the length of a portion of the data sector. The center point of the first, second, third, and fourth servo bursts are sequentially offset from the adjacent burst by a radial distance equivalent to one-half of the data track width. The quad-servo burst pattern is used with a track-following algorithm based on the quadrature value of (A+B)-(C+D) to obtain a substantially increased servo lock range.

Abstract: A multiple actuator disk drive utilizes multiple heads, associated with respective ones of multiple actuators, to read data from and write data to all tracks on the surface of a disk. The positioning of each head by the respective actuator is controlled by embedded servo-information recorded in the data tracks. The data tracks have a density of greater than 2000 tracks per inch. Utilizing two actuators provides access times which are reduced with respect to the access times provided by disk drives having a single actuator and an increased data transfer rate.

Abstract: A high level controller for maintaining communication with a host processor via a host processor interface for establishing communication paths between the host processor interface, an internal processor and a plurality of storage means. A first means receives indicia from the internal processor where the indicia specifies one of the communication paths and generates control signals for forming the specific communication path requested. A second means receives the control signals from the first means and forms the requested communication path. A third means is connected to the first and second means for controlling the communication of the system with the host processor interface in accordance with control signals generated by the first means. In this manner various data paths for communication between the host interface, internal processor and a plurality of storage means may be adaptably specified and formed to make optimum use of the system.

Abstract: A disk drive architecture controls the transfer of data between a host processor interface and a recording media that includes one or more disk surfaces for storing data. A low-level data controller controls the transfer of data between the disk surfaces and a data buffer. An interface controller controls the transfer of data between the host interface and the data buffer. An arbiter and buffer controller, responsive to data transfer requests from the low-level and interface controllers, arbitrates data storage and retrieval accesses of the data buffer. The low-level and interface controllers operate substantially independent of one another in performing their respective control operations. Consequently, data is transferred bi-directionally through the data buffer at the optimum timing for both controllers.

Abstract: A multiple actuator disk drive utilizes multiple heads, associated with respective ones of multiple actuators, to read data from and write data to all tracks on the surface of a disk. The positioning of each head by the respective actuators is controlled by embedded servo-information recorded in the data tracks. The data tracks have a density of greater than 2000 tracks per inch. Utilizing two actuators provides access times which are reduced with respect to the access times provided by disk drives having a single actuator and an increased data transfer rate.

Abstract: The read/write channel is programmatically adaptable to the media used for storing data in response to data signals and the read/write head used to transfer the data signals to and from the media. Adaptability is provided by progammable signal processing elements in the read/write channel. The programmable elements include a read threshold element for determining whether data signals transferred from the media exceed a data discrimination level determined by a first programmable value, and a data window element for determining whether data signals transferred from the media occur within a data signal window whose timing, relative to a data clock signal, is determined by the second programmable value. Additional programmable elements include an amplifier element that is programmed to provide a corresponding level of write current and a precompensation block for providing data signal precompensation.

Abstract: The disk drive system includes an actuator, responsive to an adjustment value, for adjusting the position of a data head with respect to data tracks located on the surface of a disk, and a controller coupled to the data head and to the actuator. The controller receives servo information read from the surface of the disk by the data head. In turn, the controller determines an adjustment value to be applied to the actuator. The adjustment value is calculated dependent on a predetermined variable gain factor. Where the controller determines the position of the heat is oscillating about the center line of a predetermined data track at a frequenc above a predetermined frequency, the controller reduces the gain factor applied in determining the adjustment value.

Abstract: A disk drive control architecture provides for the storage and retrieval of data with respect to a rotating media and for the transfer of data with respect to a host in response to host commands. The control architecture provides for the execution of a plurality of background processes for controlling the spin speed of the rotating media, controlling the positioning of the sensor and controlling the reading and writing of data with respect to the rotating media. The control architecture further provides for foreground processes for controlling the background processes. The foreground processes include an interface task, for coordinating the background processes in the execution of host commands and a monitor task integral to the interface task such that the monitor task is capable of implementing diagnostic commands capable of accessing all of the resources of the control architecture.

Abstract: The control system manages the storage and retrieval of data with respect to a rotating media, wherein an actuator is utilized in the selection of data for storage and retrieval. The control system includes a low level media control circuit that permits the selection of the rotational position of the rotating media and an actuator control circuit that permits the selection of the position of the actuator with respect to the rotating media. A system controller is utilized to direct the operation of the low level media and actuator control circuits whereby the system controller specifies and adjusts, in real time, the incremental selection of the rotational position of the rotating media and the position of the actuator with respect to the rotating media.

Abstract: Control and synchronization of a polyphase, brushless DC motor (used for a hard-disk system) during initial start-up of the motor, is effected by monitoring rotor position using a high-frequency commutation: A short current pulse is applied to each power phase of the motor, and motor current conducted in response thereto, is measured to determine therefrom positional information of the rotor. From such positional information the identity of the appropriate motor phase to which is applied a torque-producing current is determined. Cycles of high-frequency commutation and application of torque-producing are performed, until the rotational speed of the rotor has attained a predetermined RPM.

Abstract: An n-phase DC motor is controlled by converting a motor speed command signal generated from a programmed CPU to a motor drive signal and using this motor drive signal to apply DC power to a selected phase of the motor, the amount of applied DC power being a function of the value of the motor speed command signal. Signals representing the position and/or speed of the motor are supplied to the CPU from which the CPU detects speed errors. The speed command signal then is modified to speed up or slow down the motor so as to reduce the detected errors.