Abstract: A computer virtual memory system key-lock mechanism providing for a variety of key-lock tests and key changes depending on the type of instruction involved. This key-lock mechanism provides the opportunity for users to share use of programs and data in conjunction with the keys and locks assigned to individual users by the facility manager. The mechanism prevents unauthorized access to data and programs simultaneously present within the computer. The invention is mechanized by use of tables which record the keys and locks associated with each segment of data or code. Hardware tests each data or code segment access for compatibility between the keys and locks and causes the memory reference to be rejected if disagreement exists. The keys and locks are short digit sequences associated with the user and referenced segments.

Abstract: A computer cooling system has gaseous refrigerant compressed in a compressor and delivered to a first stage condenser. The first stage condenser includes a heat exchanger through which return coolant from the building heating system circulates to partially condense the gaseous refrigerant. The partially condensed refrigerant is directed to a second stage condenser wherein a portion of the refrigerant is diverted and flashed through an expansion valve into the second stage condenser to fully condense the nondiverted portion of the refrigerant before delivering it to the cooling coils of the computer. A pressure regulator valve controls the pressure and temperature of the diverted refrigerant in the second stage condenser to ensure that the nondiverted refrigerant is fully condensed. The used diverted refrigerant is discharged from the second stage condenser through the pressure regulator valve into an accumulator which also collects return coolant from the cooling coils of the computer.

Abstract: A network access device (NAD) is comprised of a data set for coupling to a data communication trunk, a trunk control unit (TCU) connected with the data set, a trunk control interface (TCI) connecting the TCU to an internal data bus, an internal memory, a microprocessor control and a device interface for connection to a computer or some computer peripheral device. The data set provides for two-way communication from the data trunk to the TCU. Various network access devices connected to the data trunk communicate with one another. Every normal communication between NADs includes a concurrent, predictable state change in both NADs. The response to a message from one NAD to another includes information concerning what occurred upon receipt of the message. Various latches, sequencers, microprocessor logic and registers provide for functions according to various input and output states of response.

Abstract: An electron beam lens and deflector array mounting and alignment means are provided. The array is a structure composed of several parallel plates which are held in parallel and axial alignment. The mounting means comprises four slots, one at the end of the four corners of an imaginary rectangle, formed in each facing plate surface. Four cylindrical spacer rods are sandwich between the plates, each seated in two facing slots.

Abstract: A high vacuum compatible X-Y positioning stage having an air bearing is provided. A pair of moveable carriages is mounted interior to an airtight chamber. Constraints allow movement of each carriage to only one horizontal direction, the directions of each carriage being orthogonal. Air inlet and outlet ports enter the chamber through apertures, and are mounted on the carriages and are moveable therewith. Airtight, flexible bellows form an airtight seal between the chamber and air ports at the apertures. Pressurized air communicated through the ports to the carriage is constrained to exit the carriage via small orifices about the exterior thereof to form an air bearing. The air is constrained to exit the airtight chamber through a passageway mounted in the carriage and leading to the outlet port. A stage is mounted on one pair of ports. The other pair is mounted in a fixed position. The stage is moveable in an X-Y plane vis-a-vis the fixed position on a compensated air bearing.

Abstract: Apparatus for optical measurement of the displacement and the obliquity of a test surface relative to an imaginary reference surface. An inwardly converging ring of light is projected onto a test surface. An optical system conveys an image of this ring to a photo diode array where its circumference is compared to an imaginary image of the ring projected onto an imaginary reference surface. This comparison yields the displacement of the test surface through 360.degree. of rotation, which is converted into the shape or contour of the test surface.

Abstract: A mechanism is disclosed for receiving a disk cartridge and guiding the cartridge to an operating position within a disk drive, and for subsequently ejecting the cartridge when its use is complete, all responsive to the opening and closing of the disk drive door. The mechanism for ejecting the cartridge also automatically opens a transducer head access door when the cartridge is inserted into the receiver, and automatically closes the door upon cartridge ejection. Improvements are also disclosed in the manner of mounting a lift collar designed to support the disk and hub within a cartridge, and for an improved method of adjusting the cartridge to operate alternatively in write protect and write enable modes.

Abstract: A filter cartridge for filtering fluid, such as air, within an enclosed housing, such as a disk drive, comprises a toroidal body having a pair of mating confronting halves fastened together. A pair of annular sheets of filter media are sandwiched between the halves and are separated by a ring member to engage each sheet of filter material against a respective one of the confronting halves. Fluid to be filtered flows radially through the cartridge to flow through at least two portions of the filter media. Optionally, a third sheet of filter material may be supported by the ring member to provide additional filtering.

Abstract: A digital control system is provided to regulate the speed of a brushless DC motor via pulse-width modulation. Digital counters are used to measure the difference between the time for a motor revolution and a reference time. This time difference is in turn used to control the time until the application of power during a fixed period. A motor speed decrease increases the difference in time between a motor revolution and the reference time. This decreases the power pulse delay time and results in an increased power-on time to bring the motor back up to nominal speed.

Abstract: An overlapped document detector for a document handling apparatus comprises an air knife in the primary document path to separate overlapped documents and forward them along separate ones of two secondary paths. Optical detectors focused on each secondary path, detects documents to detect an overlapped condition. A vacuum is created to maintain the documents in their respective secondary paths for detection purposes.

Abstract: A magnetic tester for hubs employed in disk-memory cartridges is provided to measure the mounting strength of hub armatures, the gross magnetic hub-retaining force, the hub-diaphragm preload strength, the net hub-retaining force, the variation of hub preload with diaphragm deflection, and the variation of hub-retaining force with magnetomotive force.

Abstract: A large-scale integrated circuit (LSI) chip has an individual voltage level sensing circuit connected with each input and output connecting pin so that isolation between the pins is maintained and so that the individual level sensor output can provide an indication of an abnormal voltage on the input/output pin. The outputs of all level sensors for all input and output pins is connected in common to the input of a comparator circuit. The comparator circuit has a fault detection threshold voltage input and provides a fault indication output signal whenever the voltage input from the level sensor circuits is outside of the detection threshold voltage range. A number of logic chips will have particular input/output pins connected together in a circuit in conventional applications. An open circuit anywhere in the interconnected network will cause some number of input/output pins dependent on the fault location to be pulled out of the detection threshold voltage range.

Abstract: A means for mounting an exchangable disk pack. The disk pack's hub includes an open ended stub with two retractable steel balls mounted adjacent the open end. The disk drive's spindle has a coaxial recess for receiving the stub. The recess has an interior annular groove adapted for registration with the balls. The stub is inserted into the recess when mounting the disk pack. When the hub and spindle are in abutment, the balls are positioned just anterior to the annular groove. The stub is mounted on a diaphragm mounted on the hub. Depression of the diaphragm moves the balls into registration with the annular groove. The balls then move from their retracted condition and into the groove under pressure from a push rod moveably mounted in the spindle recess. After the balls have been pushed aside, the push rod pops up between them and prevents their retraction from the annular groove. The lodging of the balls in the annular groove prevents the stub from being withdrawn from the recess.

Abstract: A method is presented for demultiplexing two or more streams of data multiplexed in a phase shifted arrangement. Demultiplexing is accomplished by multiplying the composite signal by an individual correlator signal for each data stream, each correlator signal being mutually orthogonal with the other correlator signals.

Abstract: The microinstructions controlling a pipeline processor are held in a control store that is partitioned into two microcode memory banks. The invention can support three modes of sequencing; single microinstruction, sequential multiple microinstructions, and multiple microinstructions with conditional branching. When a conditional branch is performed, the branch not taken path is assumed and if true, the microinstruction following the branch is executed with no delay. If the branch is taken, the guess is purged and following a one clock delay, the branched to microinstruction is executed. The invention supports these sequencing modes at the maximum pipeline rate, since the only logic between registers is the memory chips.

Abstract: A track centering servo pulse noise filter is provided. Prerecorded pulses on a disk track's even and odd half tracks are sensed by the disk's read head, preamplified, DC biased, peak detected, and stored on a FIFO basis into a noise filter comprising two sets of N analog sample and hold cells, one set for the even pulses and one set for the odd pulses. The output of each even-pulse sample and hold cell is input to a summing junction to form an average of the last N pulses. The same is done with the outputs of the odd-pulse sample and hold cells. The two summing junctions are then input to a differential amplifier to form a position error signal to the disk head track centering servo system for keeping the head centered on the track.

Abstract: Electron-beam stage X-Y positioning instrumentation is provided. The electron-beam stage has a number of metal blocks affixed to its bottom. Fixed orthogonal noncontact gage heads are used to sense the distance of the heads from the parallel faces of a proximate metal block. The position of the metal block vis-a-vis the position of the fixed referenced gage heads yields the X-Y coordinates of the stage. The stage is first coarsely positioned adjacent a preselected block.Thereafter the exact position of the stage is computed from the distances sensed by the gage heads. The electron beam electronics are automatically adjusted to the actual position of the stage thereby eliminating the relatively slow, fine positioning of the stage.

Abstract: An apparatus is disclosed for mounting a magnetic disc on a rotatable spindle. The apparatus includes a molded plastic disc-carrying hub having a circumferential collar, a central housing supporting a centering element, and a diaphragm joining the collar and housing, stiff in the radial direction but allowing axial movement of the centering element with respect to the collar. The collar includes three bosses to which a magnetizable armature plate is attached, with sufficient clearance between the plate and each boss to permit armature plate movement radially on the hub. The armature is attracted to a rotatable spindle by an annular permanent magnet mounted on the spindle. A cup formed in the spindle at its center receives the centering element and guides it to the center of the spindle, thereby centering the hub on the spindle independently of the armature as the armature is attracted to the spindle.

Abstract: A method and apparatus is provided for aligning and press-fitting connector terminals into a substrate. The terminals are initially supported together by a bandolier strip, and an alignment tool aligns the terminals with apertures in the substrate to which the terminals will be press-fitted. A pressing tool engages the shanks of the terminals to fold the bandolier away from the terminals and thereafter press the terminals into the apertures.

Abstract: This invention is an electronically steerable radar antenna which is on a cylinder section which is on the order of one wave length in circumference and in which the shape of the antenna elements on the cylinder section take the form of "O", "I" and "C" slots occupying about one-third the section circumference. Radar beams are steered by changing the phase and amplitude of the drive to the different elements of the antenna. The slots are formed as interruptions in an otherwise continuous, conductive ground plane and may be filled with dielectric if desired so that there is no surface discontinuity.