Abstract: A processor forms part of a computer network wherein the processor, designated as the User Interface Processor, operates to initialize and maintain and communicate to remote diagnostic terminals for purposes of confirming integrity of the system and also for finding the location of any faults or problems in the system. The User Interface Processor involves a microprocessor unit working in conjunction with a serial communications controller, random access memory and read only memory memories, a communications input/output (I/O) system, a multiple set of timer units and a priority interrupt controller. The User Interface Processor provides interfaces to a power control card unit, an I/O subsystem (of data link processors), and a remote terminal for diagnostic intercommunication.

Abstract: A method of recovering from an error condition during operation of a program that is modifying a data base without corrupting the data base, wherein the program includes calls to record the progress of the operation in a table in memory. On the occurrence of an error condition, the tables for all programs in operation are transferred to a disk. During error recovery, the tables are returned to memory where the information stored in the respective tables is used by each active program to restore operation of the particular program to a point where the operation can be completed without corrupting the data base. Each program is designed to interrogate its own recovery table following the occurrence of an error condition to restore operation at a point where the integrity of the data base is assured.

Abstract: A maintenance processor forms part of a computer network wherein the processor (also designated as the User Interface Processor) operates to initialize and maintain and communicate to remote diagnostic terminals for purposes of confirming integrity of the system and also for displaying data for locating any faults or problems in the network. The maintenance subsystem initiates start-up and self-test routines in a sequenced order for establishing the integrity of the units in the network. The subsystem includes means for testing two types of subsystems, that is, one having I/O controllers with self-test capability and another subsystem having I/O controllers without self-test capability. The UIP provides means for complete control of the network. It can interface the network to a remote service center where all operations such as power-up and initialization can be also effectuated.

Abstract: An improved linear actuator for reciprocating a read/write head mechanism relative to magnetic disk storage system is disclosed, including a second, supplemental solenoid coil and associated magnet means in addition to the usual arrangement, and by way of improving linearity and efficiency.

Abstract: On-line timing signal fault detection is provided by taking advantage of differential signal distribution commonly employed in digital data processing systems. An acceptance window indicative of permissible phase shift variations between the differential signals is established using a plurality of flip-flops having clock and data inputs to which delayed, undelayed, inverted and uninverted versions of the differential signals are applied in a predetermined manner. Also included is the capability of providing fault detection even when one of the differential signals is lost.

Abstract: A segmented heat sink device is provided for application to integrated circuit packages for heat dissipation purposes. The segmented heat sink device involves four duplicate sectors, each of which has a patterned set of radial fin elements through which cooling air flow may run. The reduction of the base length of each segment provides for reduction in expansion/contraction stress due to the heating and cooling cycles involved.

Abstract: Disclosed is a method and apparatus whereby each time a tape is wound upon a prescribed reel, the winding pattern may be assumed to leave the array of tape edges in a unique "edge profile" represented by the position of each winding edge as viewed from one side of the reel along a radial direction--this "profile" being interpreted as a "winding signature"; the signature may be detected photo-electrically and recorded in a convenient encoded fashion for possible use in uniquely identifying and documenting each unspooling/rewind sequence to thereby monitor tape use.

Abstract: Arbitration apparatus provides first-come-first-served access for a plurality of requestors to a commonly shared unit, such as a memory. Each requestor is provided with a counter which is advanced each cycle from an initial count until its respective requestor is granted access. During each cycle, fast programmable array combinational selection logic operates in response to the counter outputs to select the requestor which has been waiting the longest. Tie-breaking combinational logic is additionally provided for resolving ties. The speed of operation of the combinational selection logic and the combinational tie-breaking logic is chosen so that requestors can be granted access at a rate of one per cycle.

Abstract: A flexible thin film plastic access unit for placement under a pin grid array installed on a printed circuit board. The access unit provides extending exterior flaps having probe-accessible contact pads which connect electrically to each one of the underside pins of the pin grid array and permit identification of each pin that is probed.

Abstract: A power network control system has a plurality of digital modules interconnected. A master logic unit in the network communicates with a specialized protocol to slave logic units in each module. The slave logic unit can instruct a power control circuit to turn-off or turn-on various power supply modules in addition to adjusting a power module in steps of plus or minus fixed percentage amounts.

Abstract: An optical storage system employing a laser beam which is directed and focused onto an optical disk for reading and/or writing data in a track of the disk. Positioning control is achieved by providing for track following and track seeking using a plurality of interactive servo-loops. Proper focusing is maintained using focusing control circuitry which produces a focus error signal that is applied to a focus motor. This focusing control circuitry is able to return the objective lens assembly to its in-focus position so long as the objective lens assembly remains within a predetermined capture range. In the event that the objective lens assembly is outside of this capture range, a waveform generator is enabled which produces a correction signal that causes the focus motor to move the objective lens assembly back within the capture range with a velocity and for a time period sufficient to permit the focusing control circuitry to regain control and return the objective lens assembly to its in-focus position.

Abstract: Improved disk pack media for data storage is illustrated as comprising a pack of flexible magnetic recording disks which may be partitioned "end-wise".In one embodiment the disks are perforated for partitioning and also stacked in a different respective rotational orientation to facilitate end-wise partitioning. The disks are hole-encoded and either cut in different hole patterns, or else cut in a common hole pattern and stacked to dispose each in a unique rotational "misregistration" relative to all others--the result being to generate sets of "partition bores" permitting associated automatic apparatus to selectively partition the pack and expose any desired disk-side for operation thereon.In another embodiment the disks are stacked between apertured spacers about a hollow spindle, the spacers and disks being partition-apertured and stacked to generate a set of partition bores.

Abstract: An optical storage system employing a laser beam which is directed and focused onto an optical disk for reading and/or writing data in a track of the disk. Proper focusing is maintained using focusing control circuitry which produces a focus error signal that is applied to a focus motor. This focusing control circuitry is able to return the objective lens assembly to its in-focus position so long as the objective lens assembly remains within a predetermined capture range. In the event that the objective lens assembly is outside of this capture range, a waveform generator is enabled which produces a correction signal that causes the focus motor to move the objective lens assembly back within the capture range with a velocity and for a time period sufficient to permit the focusing control circuitry to regain control and return the objective lens assembly to its in-focus position.

Abstract: A programmable unit for attachment to a work-station whereby power to the work-station will be shut off after a pre-set time-period, unless work-station activity occurs before the outset of the time-period, when the pre-set time-period will initiate again.

Abstract: Each digital module in a network is provided with a local power switching control subsystem wherein the local module uses a local power switching control logic card which controls main power and subordinate power units in a predetermined sequence. Power up/down conditions or incremental/decremental voltage conditions can be effected by a local operator or by an instruction from a remote master logic unit. The power subsystem can sense failure conditions and communicate this information to the remote master unit or to a local operator.

Abstract: Described is a novel "bevel tool" and associated technique for holding prescribed magnetic head workpieces and placing them in prescribed constant angular relation with a rotary lapping means; this tool preferably including a workpiece-receiving pocket adapted to be spread apart and to resiliently grip the work, with one or more guide-faces surrounding this pocket and adapted to indicate a prescribed orientation of the work against a prescribed "lapping plane".

Abstract: Magnetic recording media having a coating containing harsh pigment like CrO.sub.2 particles and adapted for frequent contact with a head, with good durability, abrasivity, etc., accommodated by using a lubricant system including a fluoro-silicone oil and a compatible fatty-acid-ester like butoxy ethyl stearate.

Abstract: Low performance ferromagnetic oxides are taught to be convertible into high performance ferromagnetic oxides with vastly improved coercivity by suspending ferromagnetic oxide particles in aqueous media, forming a layer of the first metal on the surfaces of the particles, forming a layer of second metal on the surfaces of the first metal and lastly, forming a layer of third metal on the surfaces of the second metal. The first and third metals can be the same in preferably transition metals such as cobalt. The second metal must be different than the first and third metals such as, for example, iron.

Abstract: A system for controlling communication in a network of digital modules where each digital module has a maintenance processor which connects the digital module through a network bus to every other digital module's maintenance processor. Each transmitting module can lock up the network bus temporarily for data transmission operations to a specifically addressed receiver module. This system basically permits free communication access of any digital module to any other digital module.

Abstract: Multi-phase subroutine control apparatus for use in a data processing system which provides for the concurrent execution of a plurality of tasks in a multiprogramming and multiprocessing environment. Subroutine control operations are staged so as to share common hardware in a manner which in effect provides a plurality of phased concurrently operating subroutine control circuits wherein each circuit provides control for a different one of a plurality of concurrently executing tasks. The common subroutine hardware includes a multi-level stack for each task and a fast access return address register which permits a return address to be rapidly made available when required during execution of a task.