Abstract: A reduced height disk drive includes a suspension-actuator assembly in which a head suspension (10) is attached to an actuator (9) on the same side of the head suspension as a transducer head (8) is attached to the head suspension for writing and reading information on and from a disk (7). A spin motor cable (17) is located on the outside of a housing (2) and connected to pins (14) extending from the housing through pins (18) extending from the housing and lines (16) contained in the housing. A printed circuit board (3) having a through hole (3e) in which a connector (13) is provided connects to pins (14) extending from the housing. A flexible printed circuit inside the housing has a connector (11k) for connecting to the pins (14) and (18) at one end and a fixing member for mechanically attaching to the pins at the other end. The flexible printed circuit is attached to the pins in a folded condition.

Abstract: A disk drive slider is designed to make contact, if any, in a region of the slider which does not have a substantial effect on the fly height. Preferably, the slider utilizes a tapered center rail having a narrow tail which is closest to the disk and a pair of outside rails which are wider at the leading edge. The center rail tapers from a narrow leading edge to a wider support region and then tapers to a narrow trailing edge. The trailing edge is closest to the disk and provides virtually no contribution to aerodynamic support of the slider. Since the trailing edge does not contribute to the support of the slider, any contact induced wear can be tolerated without affecting the fly height. Even further, the wear characteristic is self-limiting. That is, after the initial wear has taken place, the likelihood of further wear is reduced.

Abstract: A disk drive contains an integrally-formed one-piece hub, clamp and rotor housing, which is preferably injection-molded plastic. In the preferred embodiment, the hub includes a hollow cylindrical portion for surrounding a set of bearings mounted on a central shaft, and a flange portion extending from the middle of the cylinder and supporting a single disk. Compliant clamping fingers on the upper surface of the flange engage the disk through its central hole. The fingers are inclined slightly outward, and include a pawl at the end of each finger. During assembly, the disk is forced over the pawls of the fingers until they engage the disk. The fingers, being slightly elastic, will deform to permit the disk to slide over the pawls, and then return to lock the disk in place. The fingers automatically center the disk about the hub axis, without the need for centering tools. The hub also serves as a housing for the rotor of a spindle motor which rotates the disk.

Abstract: A magnetic data storage disk includes a surface with a coarsely textured head landing zone and a finely textured data storage area. The coarse texture is applied over the fine texture in the landing zone without forming a step in elevation at the boundary. A method for texturing the magnetic disk includes first applying a fine texture to both the data storage area and the landing zone, and then applying a coarse texture to the landing zone only. Texturing apparatus includes peripheral disk clamps permitting axial compliant movement when the opposed disk surfaces are engaged by balanced, pneumatically biased abrading tools. A free abrasive slurry is introduced to pads carried by the tools.

Abstract: In a digital closed loop servo control system, state variables of a plant are input to an inverse system having an opposite characteristic to an internal model, and the output of the inverse system is input to the internal model. If the state variables of the plant cannot be directly observed, a state estimator is used. In that case, the inverse system receives input and output of the plant and provides output thereof to the state estimator. Input of the internal model may be inputted to the state estimator instead of inputting the input of the plant to the inverse system. In this manner, it is possible to provide a digital servo control system in which the number of bits required in calculation (dynamic range) does not depend on the amplitude of the target value.

Abstract: A disk file includes multiple disk surfaces, on which servo information is recorded, with an offset in azimuth from one disk surface to another. Each head comprises a magnetoresistive stripe for reading and an inductive write coil. The servo system reads servo information from each disk in turn, multiplexing the signals from each disk together to form a single position error signal (PES). The separation of the servo multiplexer, attached to the MR stripes, from the write multiplexer, attached to the inductive coils, avoids problems due to contamination of the servo signal by the write signal. A least squares fit is used to generate the PES from the series of servo samples from each disk surface.

Abstract: Disclosed is a disk drive having at least one disk for storing data. The disk drive includes at least one transducer for reading or writing data to or from the disk. The transducer is attached to an actuator which positions the transducer with respect to the disk. The actuator includes a controllable motor which is used to move the actuator and the transducer attached thereto. The disk drive also includes a ramp for off loading the transducer or for parking the transducer off of the surface of the disk. Also disclosed is apparatus and methods for measuring and controlling the movement of the actuator and attached transducer while the transducer is coming from a position off of the ramp and onto the surface of the disk.

Abstract: A computer system having a removable hard disk drive is disclosed. The interposer card is modified to receive a docking bay which receives a cartridge which contains a hard disk drive. The docking bay includes the male portion of a zero insertion force connector and a first circuit board to which connects to the interposer card of the computer. The first circuit board also includes circuit paths between the male portion of the zero insertion force connector and the end which connects to the interposer card of the computer. The first circuit card also includes circuitry which allows "hot plugging" of the hard disk drive to the bus of the computer and which also acts as a lockout to prevent writing to the removable hard disk drive until after the computer system has been rebooted. The docking bay also includes a spring mechanism for ejecting the cartridge. A finger lever holds the cartridge in place and can be lifted to eject the cartridge.

Abstract: A system for arbitration between competeting channels in, for example, a direct memory access (DMA) controller is described. The system arbitrates much more fairly than in the traditional `round robin` approach, especially when channel requests are not independent but instead are made and withdrawn simultaneously by groups of channels. A `turn-taken` latch is defined, and is consulted when a channel selection is made. This latch is set when a channel is serviced, and priority is given to requesting channel for which the latch is not set. When the latch is set for all of the requesting channels, an arbitrary winner is selected and the latch is reset for all except the winning channel.

Abstract: To provide a R/W circuit in which the output of an AGC is not shifted even if the output of a R/W amplifier irregularly varies during a transition time so that the detector output is not delayed. Means are provided for setting the output of a R/W amplifier 12 to a high impedance state for a predetermined time after the operation of a magnetic recording apparatus is switched from writing to reading, which comprise switches 20 and 22 connected to the outputs of the R/W amplifier 12 and an output control circuit 24 for controlling opening and closing of the switches. The output control circuit 24 opens the switches 20 and 22 for a predetermined time after switching to reading so that the irregular output of the amplifier 12 does not influence succeeding circuits.

Abstract: A method in which the wires from the heads on an actuator arm can be positioned and attached to the arm electronics automatically. A loadspring manufacturing assembly has a pair of wire carrying and positioning tails and a disposable portion. The disposable portion and the wire carrying and positioning tails each have pegs for controlling the position of the wire and for allowing twisting of the wire pairs for purposes of noise suppression. The wires are positioned about the pegs and twisted. The wires are then bonded to the loadspring assembly. A portion of the wire carrying tail has a window or opening therein. The wires are fanned out and spaced apart as they pass across the window. The wire carrying portion also has a living hinge. A portion of the wire carrying tail which includes a latching window which latches a peg is moved about the hinge and positioned at about a right angle to the loadspring. The disposable portion and the unused tail are removed.

Abstract: A laminar flow fan is adapted to fit into a the internal cavity of a fan housing (70). The fan comprises a stack of parallel disk elements (12, 14, 16, 18, 20, 22) mounted for rotation on a motor (40) with the diameters of the disk elements varying within the stack to more fully utilize the available internal space of the housing. Apparatus which uses such a fan as part of its forced air cooling system is also described.

Abstract: A method and apparatus for the efficient generation of high quality images in a computer system is provided. A user requests that one or more images be generated. Representation of each requested image and any existing images are added to an image table. Representations of a group of intermediate images are then added to the image table. Each intermediate image corresponds to a change of an image state between an existing image and a requested image. For example, if a requested image is smaller than an existing image, the scaling of the existing image is a change of image state and will result in the addition of the representation of an intermediate image to the image table. Note that the intermediate image itself is not actually computed or generated at this time. After the representation of each intermediate image has been added to the image table, image paths are built from any existing image to any requested image.

Abstract: A restriction checker generator is disclosed for generating a restriction checker capable of checking horizontal microcode instructions against restrictions which the microcode instructions must satisfy in order to be valid. The generator comprises means for transforming information representing each restriction into at least one logical test for the instruction, each logical test comprising a number of sub-tests for the values of fields of the instruction such that failure of any one of the sub-tests by an instruction indicates that the restriction is satisfied by the instruction. The sub-tests can be set-membership tests or arithmetic tests.

Abstract: Disclosed is a rotating memory device or disk drive which includes a rotating media having tracks thereon and an actuator arm which includes a head for writing representations of data to the track on the rotating memory. The head also reads representations of data from the track of the rotating memory. The head is attached to the actuator arm. The actuator arm is used to move the head to a selected position over the rotating memory such as over the track in the rotating memory. Also disclosed is an apparatus that corrects for errors of low frequency. The device includes circuitry for producing a position error signal for integrating the position error signal to produce a control signal that is used to correct for any errors in the position of the head. The device also includes circuitry for detecting cross track head speed per sector which produces a signal used to control the integration of the position error signal.

Abstract: The invention provides a circuit and method for performing test procedures on a data storage and recovery system for a magnetic storage unit. Error sample values from a read operator in a data storage and recovery system are applied to a first and a second process path to generate output signals. A source of level samples of a logical data level is also provided. The first process path generates an output signal comprising a square of each error value sample. The second process path compares the error value samples and a compare level and generates an output signal comprising a result of each comparison. The output signal of the first process path, the second process path, or the level samples is selected and is associated with a data type. In response to a coincidence of a data type associated with a selected signal with a desired data type, the selected signal is gated and then accumulated. The window during which the selected signal is accumulated may vary.

Abstract: A secondary data storage system for a host computer system includes a disk drive system having a device controller, at least a first magnetic disk and a read/write magnetic transducer positionable with respect to a recording surface of each magnetic disk. A write operation exposes data on adjacent tracks to potential damage if an off track condition occurs to the transducer during a write. A method for controlling write operations through the device controller provides backup of data in tracks adjacent to a target track for the write operation prior to the write operation occurring. The method detects occurrence of events resulting in an off track condition of the magnetic transducer relative to a target track. Occurrence of such an event triggers a determination of damage to the contents of tracks adjacent to the target track and restoration of those tracks. Write operations to the target track are blocked until shock events discontinue.

Abstract: A lubricant reservoir system for a magnetic disk near contact data storage device, which rotates in unison with the disk assembly to replace lubricant depleted from the disk surface over the life of the device, includes reservoir chambers in disk spacers with lubricant metering provided by restricted passages or textured surfaces extending radially outward from the reservoir chamber while replacement air passages extend radially inward to replace dispensed lubricant. The metered lubricant is delivered to the disk surface at a location where the surface confronting the disk is made compliant with the disk surface and the adjoining surface is beveled to form an angle of more than 90 degrees with the disk surface thereby preventing migration of lubricant away from the disk. Nonwettable surfaces may be used in metering passages, air passages, and on some beveled surfaces to further control lubricant metering.

Abstract: In a storage device, such as a magnetic rigid disk drive, data is stored at varying linear densities in the user data storage portions to increase the effective storage capacity of the device as a function of the differences in soft error rate tolerance associated with the various types of data being stored and the ability of non-alphanumeric data to be enhanced by reconstruction or smoothing rather than by an error correction code. A data type signal included with incoming data dictates the recording frequency and a control signal associated with the recorded data block is read when data is addressed to appropriately adjust the clock frequency for reading such addressed stored data.

Abstract: The hub includes a cup attached to the hub or rotating portion of the disk drive. The cup has a top. Both the cup and top have openings therein which accommodate the fixed shaft. The cup is filled with ferrofluid. The portion of the shaft passing through the cup and top is magnetized so magnetic seals are formed at the openings. Electrical charge is transmitted to the shaft via the cup and the ferrofluid. A similar arrangement is shown for a disk drive having a rotating shaft in which the cup is incorporated into the hub and a magnetized pin attached to the housing is inserted into the cup.