Abstract: An information storage apparatus is disclosed for reading and/or writing information on a rigid disk, which includes a non-Newtonian liquid bearing interface between a transducer and a storage medium, instead of a conventional air or Newtonian liquid bearing. The non-Newtonian liquid has a composition which exhibits plastic or pseudoplastic flow at high rates of shear. Preferably, the liquid is of the class of compounds whose viscosity shows a negative dependence on share rate. Thus, as the relative speed of the transducer and the storage medium increases, while their relative spacing decreases, the increasing shear rate to which the liquid bearing is subjected causes the viscosity of the liquid to reduce. Resultantly, very low flying heights can be achieved, which increases the potential storage density on the storage medium, while the reduced drag exerted on the transducer by the lowered viscosity greatly reduces the power required to rotate the medium.

Abstract: A system and method for backing-up, or storing, user-created files to a magnetic tape, or the like, and for subsequently retrieving, or restoring, selected files. Files that are backed-up utilizing one particular operating system software may be restored by a computer system utilizing a different operating system software to provide forward and backward compatibility. A directory file is created for each user file and is written to the tape. Information specific to the manner in which an operating system treats a file is stored in a first field area of the directory file and information non-specific, or common, to all operating systems is stored in a second field area of the directory file. The operating system of the computer system that backed up a file or set of files is identified on the tape and is compared, during file restoration, with the operating system of the restoring computer system to determine if the operating systems are the same or different.

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 device for accurately measuring flying heights of a read/write head in a disk drive down to zero microinches using interferometry, wherein the flying height of the head above the disk surface is calculated by directing white light to the under side of a rotating disk. An interference pattern is obtained by reflecting a first portion of the light off of the top surface of the disk and reflecting a second portion of the light off of the underside of the read/write head, and then recombining the first and second portions of light. The interference pattern is then input to a spectrophotometer, which creates an intensity profile from which the flying height of the read/write head above the disk may be calculated. A spacer layer is provided on the upper surface of the disk to increase the phase difference of the first and second portions of light, thereby allowing clear interpretation of the interference pattern at extremely low flying heights.

Abstract: In a disk drive storage system, an interface apparatus for controlling the transfer of sectors of data between a host processor and a buffer within the storage system in response to READ and WRITE command issued by the host processor. The apparatus comprises a Byte Count State Machine for controlling the transfer of a sector of data between the host processor and the buffer, an Update Task File State Machine for counting the sectors transferred by the Byte Count State Machine and generating the sector address of the next sector to be transferred by the Byte Count State Machine, a Read State Machine for controlling the processing of all READ commands and a Write State Machine for controlling the processing of all WRITE commands.

Abstract: The present invention provides a disk drive apparatus for use in computer systems where size and weight are of paramount concern. The disk drive apparatus includes a 2.5 inch disk that provides between 20-40 megabytes of storage within a footprint area of approximately 2.8 inches by approximately 4.0 inches. Further, the disk drive has a height of 0.630 inch or less. The height dimension is achieved, in part, by providing a low profile spin motor to rotate the disk. The low profile spin motor uses high energy magnets made of rare earth materials. The disk drive also employs a rotary actuator having a voice coil assembly of reduced height by using the housing as a flux return path for the magnetic fields produced by the voice coil motor. Also provided is a three-tiered housing that contains the disk which, when connected to a printed circuit board, produces the low profile disk drive apparatus.

Abstract: A flash solid state drive, having a flash solid state memory compatible with ATA/IDE Interface standards to be connected to a host for storing or retrieving sectors of data, where each sector contains 512 bytes of data, each sector is addressed by a cylinder, head and sector number CHS. The host provides, for a read or write operation, the number of sectors to be stored or retrieved, the CHS for each sector to be stored or retrieved and the data for the sectors to be stored. The solid state memory has stored therein a header for each CHS address that can be issued by the host, the header having indicia identifying the data block and indicating where the data for the data block is stored in the solid state memory.

Abstract: A transformer comprising a rotor and a stator. The rotor is positioned for rotation about a rotational axis and having a plurality of windings. At least one of said plurality of windings is positioned at a first radial distance from the rotational axis, and at least another of said plurality of windings is positioned at a second radial distance from the rotational axis. The stator has at least two windings, a first of said at least two stator windings being provided at said first radial distance, and at least a second of said windings being provided at said second radial distance from said rotational axis. Alternating ones of said plurality of rotor windings inductively couple to alternating ones of said at least two stator windings as said rotor rotates about said axis.

Abstract: A method of emulating a sequential data storage device on a random access device to permit the transfer of information in a sequential format between a host computer and a random access storage media. Commands for storing information in the sequential format from the host are transformed into commands to store data on the random access media. Commands for retrieving information in a sequential format are provided by the host to retrieve the stored information from the random access media. The commands for retrieving information are transformed into commands that retrieve the data on the random access media. Once the data is retrieved, it is then provided to the host.

Abstract: A magnetic parking device for a disk drive includes a magnet and a member for containing the magnetic field produced by the magnet. The magnetic field containing member has an air gap which is substantially parallel to the magnet flux lines of the magnetic field so that there is no fringing of the magnetic field outside of the gap. The device magnetically captures a magnetically permeable capture member provided on the actuator of a disk drive without contacting the capture member and only when the actuator enters the gap in the magnetic field containing member.

Abstract: A disk drive system for use with a host processor where the host processor employs either a look ahead command set or a tag queuing command set for communicating with the disk drive system.

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 plurality of queues where each queue is defined by a set of criteria, the queue system comprises a plurality of header registers where each header register defines a queue in the queue system and a plurality of task registers where each task register can be associated with each queue in the queue system. Each header register has a unique address and contains a previous field and a next field. Each task register has a unique address and contains a previous field and a next field. Each previous field and said next field stores the address of another register in a given queue such that each queue is formed in a double link structure. Control means is provided for dynamically assigning task registers to queues by controlling the addresses stored in the previous and next fields in each header and task registers such that each of said task registers is always assigned to a queue in the queue system.

Abstract: A serial data transmission system employing at least three transmission lines for transmitting the serial data. Each of the transmission lines can be designated as a data line 1 or as a data line 2. An encoder dynamically designates, for each binary data bit transmission period, one transmission line as data line 1 and one transmission line as data line 2 such that the transitions representing two data bits being transmitted in two successive transmission periods not occur on any one of the transmission lines. In each binary data bit transmission period, the encoder will cause a transition to occur on either data line 1 or data line 2 as a function of the value of the data bit to be transmitted during that transmission period.

Abstract: The method for assembling the drive includes: providing an assembly member; stacking a first actuator arm and a second actuator arm in an orientation where the axes of the arms are non-parallel; inserting a comb assembly between the first and second arms; rotating the arms about the assembly member to a position where the radials are in parallel; and securing the arms against rotation relative to each other. In another aspect, wherein each arm includes a read/write head having wires coupled thereto, the method further including the step of attaching a wire carrier to the arm prior to the stacking step.

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: This invention is directed to a method and a circuit for determining a relative phase shift between a data transition and a data separator window which are used to decode data read back from a mass storage device. The data separator windows provide a time interval in which a data transition must occur in order to be properly interpreted. This is accomplished by delaying the occurrence of the data transition, thereby shifting it toward the trailing edge of the data separator window, to determine if the delayed data transition occurs late within the data separator window. At the same time, the occurrence of the data separator window is delayed, thereby shifting the leading edge of the data separator window toward the data transition, to determine if the data transition occurs late within the data separator window.

Abstract: A generally rectangular outer housing is sized to fit within the full height five and one quarter inch form factor. A drawer is mounted for sliding motion within the housing along a longitudinal axis thereof from a retracted position in which the drawer is substantially fully contained within the housing to an extended position in which a forward portion of the drawer extends beyond a forward transverse end of the housing. A DAT tape drive is mounted within a rear portion of the drawer and has a forwardly opening cassette insertion slot. A cassette magazine is provided that has a plurality of vertically spaced receptacles for holding a plurality of DAT cassettes in a vertically stacked configuration. A magazine loader is mounted in the forward portion of the drawer for receiving and vertically reciprocating the cassette magazine and for selectively transferring cassettes between the magazine and the cassette insertion slot of the DAT tape drive.

Abstract: A multi-track servo-recording format includes servo zones defined longitudinally by stripes extending across the width of a storage member. Track centering signals are provided within each servo zone for locating the center of each data track on the storage member. Track-identifying indicia are provided at the beginning and end of the storage member and in each written track.

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.