Abstract: An overflow prediction scheme is provided to operate in parallel with an integer multiply within a computer to predict overflow conditions of the resultant register. The operands to be multiplied are examined to determine the position of the most significant bit. The position values are summed to determine a minimum resultant size. If the minimum resultant size exceeds the size of the data field of the resultant register, an overflow flag is set. If the minimum resultant size is less than the size of the resultant register data field, the overflow flag is not set. When the minimum resultant size equals the size of the resultant register data field, the setting of the overflow flag will depend on the signs of the expected and actual resultant.

Abstract: An apparatus and method for a cleaning process control is disclosed. The apparatus includes a printed wire circuit board that is made on a Pyrex glass or other transparent substrate. Components are attached to the printed wire circuit board and then the circuit card assembly which is formed is cleaned using a selected cleaning process. The circuit card assembly can then be inspected to determine the effectiveness of a particular cleaning process by flipping over the transparent circuit card, peering through the substrate to inspect for corrosion and solder balls. The circuit card assembly can then be cleaned more extensively and used again to check a different cleaning process.

Abstract: Disclosed is a Runout Velocity and Acceleration tester which converts an analog acceleration signal to a digital signal. The individual bits of digital data are then transformed into an exponential function. The exponential function that results is then solved for the worst case acceleration on a surface.

Abstract: A data communications apparatus transfers data between two channels, the data formats of each being incompatible with the other. Index registers receive index addresses from each channel to access a pointer in a pointer RAM. The pointer addresses a data location in a data RAM to permit data to be stored or read from either channel at the data transfer rate and byte size for that channel. Registers are provided between each RAM and at least one of the channels to concatenate smaller byte words for transfer between the RAMs and the one channel. Counter apparatus drives the pointer RAM to access successive locations in the data RAM, as desired.

Abstract: Runout in a rigid magnetic disk is reduced by sandwiching a sized shim between the disk and disk support to form a substantially smooth sinusoidal circumferential profile to the disk. A method of determining shim size is also described, employing test disks for determining optimal shim size for each class of rigid disk.

Abstract: A phase lock loop includes a phase shift apparatus to provide a plurality (i.e., four) phase-shifted clock signals from the VCO. A phase selector is responsive to a triggering signal from a one-shot multivibrator to select the one phase-shifted clock signal next following termination of the trigger signal. The one-shot is responsive to a change between the read and write mode to initiate operation of the phase selector. As a result, the initial phase error between the input signal (read pulses or write clock) and the clock signal of the phase lock loop is no more than 1/8 window.

Abstract: A 1,7 decoder is repeatedly initialized during reading of the synchrofield of the record. The decoder includes an oscillator responsive to the record to produce a binary read signal having a frequency f. A first divider produces a source data clock signal having a frequency 2/3 f. A second divider produces a data partition clock signal having a frequency 1/3 f. A phase synchronizer is responsive to the data partition clock signal to synchronize the source data clock signal. An initializer is responsive to the read signal recovered from the preamble of the record to synchronize the data partition clock signal.

Abstract: A flexure for a rotary actuated load arm for use in a data storage system is disclosed. The flexure attaches a slider to the load arm. The slider carries a transducer over a track on a disk. The disclosed flexure has a high enough radial stiffness to prevent the slider from sliding and sticking in a position where the transducer cannot read or write data on the desired track.

Abstract: A head/arm lock mechanism includes a pawl mounted to the armature of a bistable solenoid, the armature being stable in either of two rotary positions. The armature and pawl are limited to move through an angle less than that defined by the stable positions of the armature, so that the armature is biased by the magnetic circuit of the solenoid to one or the other limit positions. When the head/arm is in position to be locked, the solenoid is energized to lock against a spacer on the head/arm and the magnetic circuit continues to hold the pawl in a lock-engaging position upon de-energization of the solenoid. When the head/arm is to be unlocked, the solenoid is again energized to unlock the pawl from the spacer and the magnetic circuit continues to hold the pawl in an unlock position upon de-energization of the solenoid.

Abstract: A 3/2 frequency divider employs two D-type flip-flops, an OR gate and an AND gate arranged to respond to an input signal at a frequency f to derive an output signal at a frequency 2/3 f. The frequency divider is employed in a code converter to encode or decode 1, 7, 2, 3 codes.

Abstract: This application teaches that more accurate measurements of clock skew can be had by providing a clock monitor pin directly connected to the clock bus internal to the VLSI chip.

Abstract: Sequential faults are not tested for adequately when using test input operands generated in the chip from a random number generator to test the logic circuits in a very large scale integrated (VLSI) chip. Accordingly this application teaches the efficient construction of a test operand generator, using an input register with properly randomized feedback to break up sequential patterns which would otherwise develop in the input register.

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: This patent teaches multiplexing MR head circuits to an off-chip capacitor in novel ways to eliminate excessive numbers of off-chip components. The bias current is switched off for each MR head when it is not in use and the bias current is supplied only to the MR head being employed at a given time. On the sensing side, the invention teaches connecting a single capacitor across a plurality of pairs of transistor emitters, each pair of transistors having their collectors (assuming NPN) connected to the sense lines of one of the MR heads. A number of example circuits are illustrated and described, including one employing PNP transistors.

Abstract: A compliant S-shaped lead for resiliently supporting an integrated circuit chip package in spaced relation generally parallel to a printed circuit board. The S-lead bends and twists to absorb forces which would otherwise be exerted on solder joints due to temperature cycling and vibration. The symmetrical S-lead self-centers on both the package and PC board to provide minimum stress. The leads are held by a support strip for connection to the chip carrier. Thereafter, the support strip is removed and the carrier positions the leads for connection to the circuit board.

Abstract: An encoding/decoding system for 1,7,2,3 codes employs an oscillator having a frequency f and dividers providing signals at frequencies equal to 1/3 f and 2/3 f. A code converter is responsive to the three signals to encode or decode data. A 3/2 frequency divider employs two D-type flip-flops, an OR gate and an AND gate arranged to respond to an input signal at a frequency f to derive an output signal at a frequency 2/3 f.

Abstract: An apparatus for testing the surface properties of a material is disclosed. The apparatus includes an indentor which is suspended above the surface of a sample and dropped onto the sample. Several testing methods are also disclosed. Surface toughness is measured by dropping the indentor from a variable height and inspecting the surface for failure. Thin film strength is tested by making several drops from various heights and inspecting the surface for flaking of the layer. In addition, damping capacity can be measured by comparing the kinetic energy of the resulting from the drop of the indentor to the strain energy measured by a probe on the opposing surface of the sample.

Abstract: A thin film magnetic recording head has a flux path in which during writing magnetic saturation occurs in the throat section of the leading pole rather than in the trailing pole. This keeps the stray magnetic fields generated in the area where the saturation occurs during writing from distorting the just-recorded data pattern in the medium, since the leading pole is spaced sufficiently far from the data pattern as it is created adjacent the trailing pole. Preferably, this is accomplished by making a cross section area of the flux path in the leading pole throat section physically smaller than the minimum cross section area in the remainder of the leading pole or in the trailing pole and is throat section.

Abstract: An apparatus and method for positioning a transducer over the center of a track is disclosed. An arm carries the transducer. Embedded in the arm is a heating element. The heating element is positioned so that the linear expansion or contraction of the arm resulting from the temperature rise or drop due to the amount of heat applied to the arm by the heating element will move the transducer across the track. In operation, a constant amount of heat is initially applied to the arm to center the transducer. During tracking, a circuit varies the amount of power applied to the heating element so that the transducer is kept over the center of the track.

Abstract: In an optical recording system, a media disk for writing information has a plurality of information tracks with preformatted clock location indications written on the tracks. Writing is accomplished by making a written indication at a predetermined location between preformatted clock locations where the predetermined location is representative of the particular data to be written. Proper location of the preformatted clock location indicia on adjacent tracks provides for proper track crossing information when track addressing occurs as well as proper address location on particular tracks.