Abstract: Error detecting and correcting operations for a plurality of input bits comprised of input data bits and associated check bits are implemented using two IC chips in order to overcome chip output limitations. In addition, redundancies derived from the use of two IC chips are employed to provide automatic self-checking of the detecting operation of each chip. The use of two identical IC chips for this purpose is made possible by employing a specially chosen inversely symmetrical Hamming code and by wiring the input data bits and the input check bits in an inverse manner with respect to the input terminals of the two IC chips. As a result, even though each IC chip performs the same error detecting and correcting operations, it does so inversely with respect to the input data bits and the input check bits so that each IC chip is able to provide one-half of the required output bits.

Abstract: A method employing two identical IC chips for providing error detecting and correcting operations on a plurality of input bits comprised of input data bits and input check bits, wherein a single one of the IC chips has an insufficient number of available outputs to provide all of the required outputs. The method includes applying the input data bits and the input check bits to the input terminals of each IC chip in an inverse manner relative to one another, and then performing the error detecting and correcting operations on each chip in accordance with an inversely symmetrical Hamming code. As a result, even though the same detecting and correcting operations are performed on each IC chip, they are performed in an inverse manner with respect to the input data and input check bits so that each IC chip is able to provide one-half of the required output bits.

Abstract: Error detecting and correcting operations for a plurality of input bits comprised of input data bits and associated check bits are implemented using two IC chips in order to overcome chip output limitations. The use of two identical IC chips for this purpose is made possible by employing a specially chosen inversely symmetrical Hamming code and by wiring the input data bits and the input check bits in an inverse manner with respect to the input terminals of the two IC chips. As a result, even though each IC chip performs the same error detecting and correcting operations, it does so inversely with respect to the input data bits and the input check bits so that each IC chip is able to provide one-half of the required output bits.

Abstract: Disclosed are air seals adapted to be so engaged in a receiving card rack slot as to thrust out against the opposed slot bases and thus establish "base-engaging" retention forces, this effected in some embodiments by forming a base-engaging flexure strip along each tongue of the seal to that, despite dimensional and other variations, each flexure strip will be thrust-away somewhat from its slot-forming channel, when the seal is firmly seated in a slot.

Abstract: Disclosed are reciprocating carriages carried on roll bearings engaged on guide rails, where some of the bearings are made flexible to be compliantly engaged against a rail surface.

Abstract: A method employing two identical IC chips for providing error detecting and correcting operations on a plurality of input bits comprised of input data bits and input check bits, wherein a single one of the IC chips has an insufficient number of available outputs to provide all of the required outputs. The method includes applying the input data bits and the input check bits to the input terminals of each IC chip in an inverse manner relative to one another, and then performing the error detecting and correcting operations on each chip in accordance with an inversely symmetrical Hamming code. In addition, by taking advantage of redundancies in the performance of error detecting operations, the method also provides for automatic self-checking of chip operations.

Abstract: A relatively large plurality of relatively small, independently operating disk subsystems are coupled to a read/write interface containing error circuitry and data organizer circuitry. The data organizer circuitry organizes read/write data for read/write communication with the disk subsystems via the error circuitry such that the overall system appears as a large, high capacity disk system having an unusually high fault tolerance and a very high bandpass.

Abstract: A program scanner for a processor having multiple internal streams of instruction and data flow scans a sequence of incoming codes, and employs a plurality of rams to detect various types of syllables in that code. The contents of these rams are signals indicating the various types of codes possible with the output of the rams then being multiplexed to provide an output indicating which syllables can be grouped together for transmission to various units of the processor.

Abstract: A magnetic coating composition is disclosed of the type having magnetic particles dispersed in a resin binder. The improvement comprises the use of a solvent system including a dibasic ester wherein the solvent system has an initial Hansen three-dimensional solubility parameter range of approximately 10.5 to 11.0 and a Hansen three-dimensional solubility parameter range of approximately 9.3 to 10.0 after approximately 99% of the solvent has been evaporated from the binder.

Abstract: Improved transducing techniques and arrangements; the embodiments particularly adapted for co-action with disk drive apparatus for handling flexible disk packs, and including a partitioning shield, flexure-bar mounted transducer head under the shield, along with disk-cleaner/stabilizer means--especially where these are arrayed in the form of a double-opposed transducer assembly adapted to be so manipulated into the pack as to double-partition the pack away from a selected disk on which opposed dual-transducing operations may be carried out.Such arrangements eliminate the need for separate pressure-pads, incorporating them on opposed-heads adapted to transduce on both sides of a record mounted on the ends of respective pivotable flexure-bars. Such cleaner/stabilizers can be opposed, engaged an intermediate record, squeezingly.

Abstract: Described is a technique and associated fixture for lapping magnetic recording heads in a group such that each head is mounted on a "free floating" part in the fixture, being biased for lapping only by the weight of this part and being individually removable during lapping mode; and also characterized by capability for pivoting the fixture to change the lap-angle of all such heads in common to a new constant prescribed angle, the parts also being selectibly kept non-rotatable in the fixture.

Abstract: Improved spacer means for flexible magnetic disk pack storage systems are illustrated in the embodiments, each preferably comprising a set of fingers arrayed on each disk.

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: 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: Apparatus for precisely edge aligning and offsetting or jogging stacks of sheet items wherein two oppositely disposed alternately actuated continuously rotating paddle members each produce driving forces at right angles to one another effective to force each item first in one direction and then in another direction at right angles thereto such that the sheet items operational with respect to any paddle are caused to be stacked in offset alternating piles against confronting opposite walls of a stacker frame member.

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 multi-purpose register formed of various cells of a customized integrated circuit gate array chip having input gate cells, multiplexor cells, flip-flop cells and output gate cells. The flip-flop cells may be segmented into registers of different widths or may be employed as individual flip-flop cells depending upon the mode in which the register array is to be employed.

Abstract: A system which enables a protected program to run only a selected plurality of computers includes a respective unique key Ki for each computer of the plurality, the key being triple encrypted in the form E.sub.FK [E.sub.Ki [E.sub.FK [Ki]]]. A respective module is coupled to each computer of the plurality. A checker program in each computer responds to a request to use the protected program by performing a single decryption procedure E.sub.FK.sup.-1 on the triple encrypted key and sends the result to the module as a message. The module performs a single decryption procedure E.sub.Ki.sup.-1 on the message and sends that result back to the computer. The checker program receives the module's result and performs another single decryption procedure E.sub.FK.sup.-1 on it to obtain key Ki. Then the checker program uses key Ki to decrypt an identifier, and proceeds with the execution of the protected program only if it is identified by the decrypted identifier.

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.