Abstract: Run length limited codes, such as (1,7) codes are recovered with a dual channel recovery system in which the high resolution channel normally supplies the output (recovered) signal. The low resolution channel includes a detector, such as a delay device and gate, to detect a predetermined absence of transitions in the low resolution signal (which is indicative of long strings of successive zeros) to inhibit the high resolution channel from supplying the output. The result is to effectively block the high resolution channel from providing a false output.

Abstract: Servo data, including three types of servo patterns distinguishable by phase, are stored in concentric servo tracks on a magnetic information storage disk. Each servo track includes a plurality of only one type of pattern, with consecutive tracks arranged in a repeating sequence of the three servo pattern types. For phase recognition, the pattern types further are arranged in a repeating sequence of angular sectors, each sector having a plurality of but one type of pattern. The servo patterns in a given storage track thus are always angularly offset from the servo patterns in the next adjacent tracks. This permits the use of servo patterns having a radial dimension greater than the separation between adjacent tracks, increasing servo signal reliability and transducer dynamic range.

Abstract: A double density plug and socket electrical connector employing the same form factor as existing 50 pin subminiature "D" connectors. Adapted for use on printed circuit boards the connector can compatibly interconnect 50 pin or 100 pin electrical connectors. The double fifty plug-socket connector can carry a multiple byte wide SCSI bus.

Abstract: A self-loading negative pressure air bearing slider is formed having side vents. The side vents allow for repeatable manufacturing of the basic slider in fewer steps while retaining the desirable features of high stiffness and substantially constant flying height found in negative pressure air bearing sliders.

Abstract: A thin film magnetic data transducer carried on the end of a conductive flyer has its magnetic pole electrically connected to the flyer to prevent electrostatic discharges between the flyer and the pole tip from eroding the pole tip. The winding of the transducer is also electrically connected to the flyer either through a high resistance, through a diode with high forward and reverse voltage drops, or through a fusible link, so as to bleed off static charges on the winding without their arcing through to the magnetic pole and damaging the insulation between the winding and the magnetic pole. These embodiments avoid any degrading of the data readback signal.

Abstract: A method and apparatus for increasing the amount of data capable of being stored in a magnetic storage device is disclosed. Basically, a magnetic characteristic of the disk to head interface is measured at several locations on the disk. The frequency for writing and reading the data is optimized in terms of the required resolution and the magnetic measurement. The read and write modes are then varied, based upon the optimized frequency, such that data is written on the disk at a frequency substantially equal to the optimized frequency and read from a disk having data recorded at the optimized frequency.

Abstract: A programmable logic array is constructed of independently controllable logic building blocks of two types and special output logic to perform desired logic functions. The first building block is a functional element which is capable of performing any logical function of its input data to create output data. The functional elements shown are based on three inputs with a single output. The second basic type of building block is a pass-through/hold device which may either pass its input directly through as an output, or which may latch and hold the input until clocked. A plurality of logic levels or ranks of elements of the first type and ranks of the second type are interconnected so that the output can be various functions of the inputs. The logic array described here has first and second logic levels consisting of functional elements followed by a third level of pass-through/hold devices. The fourth and fifth logic levels are functional elements and pass-through/hold devices.

Abstract: A double precision approximate quotient network determines the quotient of a 2n bit number and an n bit number where the n bit number has a value of 2.sup.n-1 -2, 2.sup.n-1 -1, 2.sup.-1, or 2.sup.n+1. Apparatus determines the 2's complement and 2 times the 2's complement of the n most significant bits of the 2n bit number. A select circuit is responsive to the value of the n bit number to select one of (a) the 2's complement of the n most significant bits of the 2n bit number, (b) 2 times the 2's complement of the n most significant bits of the 2n bit number, (c) zero, or (d) the n most significant bits of the 2n bit number. A shift register right shifts the 2n bit number one place. An adder adds the shifted 2n bit number to the number selected by the select circuit to determine the quotient. The apparatus is particularly useful in determining a double precision approximate quotient for use in double precision floating point divide and decimal divide operations.

Abstract: This invention teaches a method for producing small machined parts by laser including a description of how to avoid sensitive edges of the work piece being machined and how to control beam size for maintaining uniform cavity depth over a relatively long work piece and also how to generate non-uniform cavity depth profiles on the surface of one or more parts. The invention also teaches that such a process can be used to produce satisfactory negative pressure air bearing sliders which are used to support the transducing magnetic heads for high density magnetic storage disk drives.

Abstract: A method and apparatus for placing a ferrite core in the slot of a pad of a ferrite head. A circular magnet is mounted below a non magnetic table on a slider slidable along a line. The pad is clamped on the table with its slot exposed and aligned along the line and the center of the magnet. When the ferrite core is placed on the table near the magnet, it stands on edge, aligned along a radial line of flux from the magnet. As the magnet is slid towards the slot, the core follows the center of the magnet, aligned along the centerline of the slot following the radial line of flux. The core slides into the slot and is thereafter bonded to the pad.

Abstract: This invention provides for a method and apparatus for assembly of complex systems by human operators with the assistance of automatic machinery. The machinery employes a lighted probe to direct the operator to insert a part of the lighted location and the machinery tests for proper seating of the part. The machinery is integrated into a larger automated system which enhances its automatic part location indicating function by allowing and correcting for mislocation of real world coordinates from ideal coordinates. Also taught is a method for integration fo the assembly operation from the design stage through the production phase.

Abstract: Apparatus is shown for mixing and dispensing an epoxy adhesive. An epoxy resin and its associated curing agent are simultaneously loaded from separate cartridges into a length of flexible PVC tubing, part of which is contained between a rotor and a stator. Bearings, mounted rotatably about the rotor, engage and travel along the tubing as the rotor is revolved, each bearing compressing the tubing at its point of engagement. The tubing, repeatedly compressed and released by each bearing in succession, kneads the epoxy resin and curing agent into a homogeneous mixture. From the tubing, the epoxy mixture is deposited on a moving carrier tape and forms a continuous bead. Downstream, a control tape is spaced apart from the carrier tape and moves in the opposite direction. As the bead encounters the control tape, the control tape removes part of the bead material from the carrier tape and plastically forms the remaining mixture into a film of a uniform thickness substantially less than the bead diameter.

Abstract: An improved ring oscillator for VLSI chips is shown, formed at the chip periphery. It may have specific initiation gates and have additional parasitic capacitance added to the ring to enhance accuracy. The circuit elements used for the ring are the same as those used for more centralized circuits.

Abstract: A flexible head connector with a ground plane for connecting a daughter board to a mother board.

Abstract: Apparatus for assembling a pair of high strength magnets and the common pole piece into a unit for use in a disk drive includes a bed with a channel in which the magnets can slide or translate, and a stop centrally located in the channel to prevent execessive impact between the magnets as they slide under the force of mutual attraction toward each other. A recess in the bottom of the channel below the stop is adapted to receive the pole piece, and the attractive force between the pole piece and the magnets firmly attaches the magnets to the pole piece in the desired location after they have been properly positioned with respect to the pole piece by interaction of the stop and channel walls with the magnets.

Abstract: A method and article of manufacture allows great accuracy in machining the edge of a face on a prism to a predetermined position respective a feature carried on the face and formed by deposition of insulating material. The preferred application for this invention is in accurately machining the transducing surface of a disk memory transducer assembly so that the throat height of the thin-film head carried on an end face of the assembly has a precise value.

Abstract: Automatic manufacture of integrated circuit packages including a leadless chip carrier is facilitated by providing, in strip form, flexible tape circuitry having a dielectric layer and a conductive layer. Through selective etching, regularly spaced central openings are formed in the strip for subsequent placement of the leadless chip carriers. The arms are formed in the conductive layer and extend into the openings. Members are formed in the dielectric layer around each opening. A leadless chip carrier is placed in an opening and its pads are bonded to the arms. With the chip carrier thus secured to the strip, its position is controlled by the strip drive means which moves each chip carrier to assembly and testing stations. Electrical testing is accomplished with probes adapted to contact the arms. Temperature cycling and other mechanical tests also are conducted with the chip carrier attached to the tape.

Abstract: An electrical power connector for PC boards or bus bars having low insertion force and low voltage drop across the connector. The connector features a female receptacle having a double set of opposing rows of multipoint spring contacts mating with a two-tiered male plug. The spring contacts make electrical contact to the tiers of the male plug.

Abstract: A circuit for phase locking a clock signal to a series of data pulses includes a wide band signal generator, a power supply, a flip-flop, a loop filter and a voltage controlled oscillator ("VCO"). The circuit adds current or subtracts current from the loop filter which controls the voltage across the VCO. The voltage across the VCO determines the frequency of the clock signal which it outputs. During the PLO sync zone, the circuit adds or subtracts increased amounts of current from the loop filter during every other pulse to cause greater amounts of correction in the frequency of the clock signal during every other pulse. The wide band signal generator, which includes a component which decays over time, operates only during the PLO sync zone. The circuit uses a flip-flop triggered by each data pulse to either send the current from the wide band signal generator to ground or add it to the constant current level produced by the power supply.

Abstract: A connecting device is disclosed for electrically and mechanically linking multiple circuit boards arranged in two perpendicular stacks. The connecting device includes two identical connectors, each with a plurality of outwardly extended electrical socket contacts, and a pair of opposite, electrically insulative shoulders projected outwardly beyond the socket contacts. Electrical pin contacts are recessed into the shoulders. The pair of connectors can be engaged when in facing relation, with one of them rotated 90.degree. relative to the other. As the connectors are moved toward engagement, each shoulder of each connector enters into a nesting relation between the opposed shoulders of the other connector, pre-aligning the opposed pin and socket contacts. The shoulders have inclined edges at their outer faces, to assist in capturing their associated opposed shoulders and guide them, in a self-aligning manner, into the nesting relation. The connectors require a 90.degree.