Patents Represented by Attorney, Agent or Law Firm Barry N. Young
  • Patent number: 5263127
    Abstract: The present invention includes an approach to improving run-time performance of rule-based systems. A series of testing element nodes making up a testing element is adapted to a match discrimination network utilized in an expert system to permit scanning of incoming data prior to traversing large segments of the nodes in the match discrimination network. By placing a series of testing element nodes into a traditional match discrimination network, interaction among data objects and nodes of the match discrimination network are minimized.
    Type: Grant
    Filed: June 28, 1991
    Date of Patent: November 16, 1993
    Assignee: Digital Equipment Corporation
    Inventors: William Barabash, Steven A. Kirk, William S. Yerazunis, Kenneth A. Gilbert
  • Patent number: 5261002
    Abstract: A technique for issuing and revoking user certificates of authenticity in a public key cryptography system, wherein certificates do not need expiration dates, and the inconvenience and overhead associated with routine certificate renewals are minimized or avoided entirely. A Certification Authority issues certificates as required, and issues a blacklist having a start date, an expiration date, and an entry for every invalid certificate issued after the start date. Users assume that every certificate issued prior to the blacklist start date is invalid, and that invalid certificates issued after the start date will be included in the current blacklist. A new blacklist is issued prior to expiration of the current one, and the blacklist start date is changed only when the blacklist becomes unmanageably long.
    Type: Grant
    Filed: March 13, 1992
    Date of Patent: November 9, 1993
    Assignee: Digital Equipment Corporation
    Inventors: Radia J. Perlman, Charles W. Kaufman
  • Patent number: 5261113
    Abstract: In a data processing system in which a processing unit can execute both scalar and vector instructions, the use of a single operand register file to store both the scalar operation operands and the vector operation operands is described. An instruction is included in the instruction repertoire in which a field is decremented (until a zero field is reached) to provide the next sequential operand address and to indicate that the prior operation is to be repeated on the next sequential operand.
    Type: Grant
    Filed: September 11, 1990
    Date of Patent: November 9, 1993
    Assignee: Digital Equipment Corporation
    Inventor: Norman P. Jouppi
  • Patent number: 5257264
    Abstract: A purging station selected for removal of no-owner frames in a token ring network, and a corresponding method for its operation. The purging station initiates a purge cycle only if the network is not "idle" and, optionally, only if the network is not "near fully loaded," these terms being defined in relation to a token cycle. Therefore, no unnecessary purge marker frames are transmitted onto the network when it is idle or near fully loaded. Once purging is initiated, the purging station transmits at least one purge marker frame onto the ring network, and strips data received from the ring until a purge termination flag is set, upon detection of a received purge marker frame, a received token, or detection of a ring re-initialization procedure.
    Type: Grant
    Filed: July 29, 1991
    Date of Patent: October 26, 1993
    Assignee: Digital Equipment Corporation
    Inventors: Henry S. Yang, Kadangode K. Ramakrishnan
  • Patent number: 5249090
    Abstract: A device for fixing a disk pack to the drivable shaft of a disk store such that it can be removed comprises a spring lock washer which is mounted in a slot at the upper end of the shaft. A cup spring pre-tensioned against the disk pack is supported with its inner, inclined supporting surface against the spring lock washer, which is itself supported by the upper inclined side wall of the slot.
    Type: Grant
    Filed: December 12, 1991
    Date of Patent: September 28, 1993
    Inventor: Wolfgang Fehse
  • Patent number: 5246294
    Abstract: A self-lubricating hydrodynamic spindle bearing for support of a spindle of a magnetic disk drive assembly includes a crankcase design which provides large reservoirs for oil storage with an air cover in communication with the ambient environment through an air vents provided by clearance seals formed between respective central passages of housing-sealing endcaps and the shaft. The crankcase reservoir volume is defined within the bearing so that natural body force effects cause the lubricant to be fed into the hydrodynamic bearing. A leak-preventing capillary trap of minimal continuous axial length may be provided at the clearance seal for passive capture of wandering lubricant when the bearing is at rest. Full evacuation of lubricant trapped at the clearance seal is achieved toward the interior of the housing by centrifugal pumping, e.g.
    Type: Grant
    Filed: December 14, 1992
    Date of Patent: September 21, 1993
    Assignee: Digital Equipment Corporation
    Inventor: Coda H. T. Pan
  • Patent number: 5243495
    Abstract: A removable self-contained rigid disk drive has a head and disk assembly (HDA) and controller enclosed by a top and bottom cover. The industry standard form factor drive is externally dimensioned to be removably installable in a disk bay of the same form factor. HDA components are mounted on one side a composite plastic-steel base, and the controller is attached to the other side. The controller is proved with an industry standard electrical interface for connecting the drive with a host computer system with a complementary electrical interface. The covers of the drive are made of metal to reduce electromagnetic interference when the drive is in operation.
    Type: Grant
    Filed: March 20, 1992
    Date of Patent: September 7, 1993
    Assignee: Digital Equipment Corporation
    Inventors: John D. Read, Charles E. Vaillant, Gordon J. Norquay
  • Patent number: 5243308
    Abstract: An electromagnetic noise filter has a plurality of U-shaped wires passing through a ferrite core. Some of the wires are singly fitted in throughholes, whereas other wires are commonly fitted in throughholes. The wires can be interconnected to provide for impedance to both differential-mode and common-mode noise.
    Type: Grant
    Filed: April 3, 1992
    Date of Patent: September 7, 1993
    Assignee: Digital Equipment Corporation
    Inventors: Boris I. Shusterman, Robert Curtis
  • Patent number: 5242761
    Abstract: A magnetic recording medium and method of manufacture therefor uses a vertically magnetized film (4) backed by a nonmagnetic substrate (1) made of e.g., glass; a Permalloy.RTM. layer is interposed between the magnetized film and the substrate. An additional layer (3) of a soft amorphous magnetic material, e.g. Co-Zr-Nb or Co-Zr of a suitable thickness (e.g. 50 nm) is interposed between the vertically magnetized medium and the Permalloy.RTM. layer for improving crystalline orientation of the vertically magnetized film and the Permalloy.RTM. layer. The additional layer (3) may be deposited by high frequency sputtering while applying a magnetic field othogonal to the substrate.
    Type: Grant
    Filed: July 3, 1990
    Date of Patent: September 7, 1993
    Assignee: Digital Equipment Corporation Japan
    Inventor: Yoichi Uchiyama
  • Patent number: 5241621
    Abstract: A knowledge processing system and a method for operating same for interacting with a user of the system. The system includes a user interface for prompting the user to enter information and for receiving entered information from the user. The user interface is coupled during use to a knowledge model processor (10) that includes a Dialogue Control Interpreter (16) that provides structured messages to a user so as to elicit responses from the user concerning Imperatives of the user, Situations of the user, Knowledge known to the user, and Executive Agents known to the user. This information is stored in a User Awarenesses database (18). The Dialogue Control Interpreter operates in accordance with predetermined dialoguing Imperatives (20) to elicit, record, and access user responses in sequences that guide and motivate the user to follow predetermined sequences of thought, based on the recorded User Awarenesses database of Imperatives, Situations, Knowledge, and Executive Agents.
    Type: Grant
    Filed: June 26, 1991
    Date of Patent: August 31, 1993
    Assignee: Digital Equipment Corporation
    Inventor: Ronald G. Smart
  • Patent number: 5241639
    Abstract: Disclosed is a method for operating a cache memory. In response to a write transaction, data is written to a location in a foreground memory that is part of the cache. A modified bit is set in the foreground memory indicating that the data must be written back to main memory. A registration bit is checked in the foreground memory location to determine whether the address is registered. The location of the foreground memory is written to a registration memory in the cache if the registration bit is not set. The registration bit is set in the foreground memory, in conjunction with writing the address of the memory location to the registration memory, to indicate that the address has been registered. In response to a subsequent transaction, the foreground memory location can be selected to store new required data. The modified bit is checked to determine whether the data stored in the foreground memory location must be written back to main memory before the location can be used to store the new data.
    Type: Grant
    Filed: January 19, 1989
    Date of Patent: August 31, 1993
    Assignee: Digital Equipment Corporation
    Inventor: Fredericus H. J. Feldbrugge
  • Patent number: 5240740
    Abstract: A two-pole inductive magnetic head for a computer disk drive assembly. The head generates a stream of main pulses and secondary pulses in a readback waveform when reading data from a magnetic medium, each bit of read data represented by a respective main pulse. The head includes an integrating feature which reduces the amplitude and high frequency content of the secondary pulses in the readback waveform so as to ease the task of electronically isolating the main pulses for downstream processing of the read data.
    Type: Grant
    Filed: December 9, 1992
    Date of Patent: August 31, 1993
    Assignee: Digital Equipment Corporation
    Inventors: Karl A. Frey, Michael Mallary
  • Patent number: 5239630
    Abstract: An improved arbitration technique for a computer network system in which multiple nodes communicate using a shared bus, and at least one node has no knowledge of the current status of the arbitration taking place between all nodes in the system. Such a node is called a "deaf node". Each node in the system is assigned an initial arbitration count number, for example, N+1, where N is the node number assigned to the node. The arbitration count number is the number of quiet slots a node must count before trying to transmit on the system bus. The length of a quiet slot is determined by a particular system's electrical characteristics. One quiet slot is reserved as the "deaf node quiet slot", during which a deaf node may transmit. In response to a transmission occurring in the deaf node quiet slot, each node in the system reinitializes its arbitration count number to its initial arbitration count number.
    Type: Grant
    Filed: July 2, 1990
    Date of Patent: August 24, 1993
    Assignee: Digital Equipment Corporation
    Inventors: Richard F. Lary, Xi-Ren Cao, Mohammad V. Abidi, Nii Quaynor, Fernando Colon-Osorio
  • Patent number: 5239423
    Abstract: In a method and a circuit arrangement for recovering a digital signal having digital pulses from a recorded signal which is read by a read head of a storage device, the shape of the recorded signal, being a reproduction of the digital signal, is compared with the shape of a normal read signal previously stored as a comparison pattern of voltage values. In the case of agreement, which is given on the presence of a certain correlation, the recorded signal is evaluated as a digital pulse and otherwise on non-agreement as a digital non-pulse.
    Type: Grant
    Filed: June 27, 1991
    Date of Patent: August 24, 1993
    Assignee: Digital Equipment Corporation
    Inventor: Siegbert Sadowski
  • Patent number: 5235617
    Abstract: A transmission media driving system for receiving high data rate serial binary data signal, dividing the signal into two or more lower data rate signal paths, modified duobinary encoding the signals and transmitting the signals on respective two-conductor transmission lines. The system includes ample encoding circuits for generating control signals and a line driver circuit, associated with each encoding circuit, that is responsive to the control signals to drive one of the transmission lines with the modified duobinary encoded signal through a transformer. The driver circuit includes multiple current sources that are switched to conducting or nonconducting states in response to the control signals to drive currents through a primary winding of the transformer to achieve appropriate levels of the encoded signal.
    Type: Grant
    Filed: June 11, 1991
    Date of Patent: August 10, 1993
    Assignee: Digital Equipment Corporation
    Inventor: William C. Mallard, Jr.
  • Patent number: 5235644
    Abstract: A decryption method, and associated cryptographic processor, for performing in-line decryption of information frames received from a communication network through a first in-line processing stage. As an information packet is streamed into the cryptographic processor, a determination is made to an acceptable level of probability whether the packet contains data that should be decrypted. The decision whether or not decrypt is made by analyzing the incoming packet header, recognizing a limited number of packet formats, and further parsing the packet to locate any encrypted data and to make sure that the packet is not a segment of a larger message. Falsely decrypted packets are looped back through the cryptographic processor, to regenerate the data that was falsely decrypted. Decryption and encryption are performed in such a manner that a false decryption is completely reversible without loss of data.
    Type: Grant
    Filed: June 29, 1990
    Date of Patent: August 10, 1993
    Assignee: Digital Equipment Corporation
    Inventors: Amar Gupta, Butler W. Lampson, William R. Hawe, Joseph J. Tardo, Charles W. Kaufman, Mark F. Kempf, Morrie Gasser, B. J. Herbison
  • Patent number: 5233616
    Abstract: This invention relates to a write-back cache which is protected with parity and error correction coding ("ECC"). The parity and ECC codes are generated by a memory interface when data is transferred by main memory to the central processing unit ("CPU") associated with the cache. Thus, all data originating in main memory will be parity and ECC encoded when it passes through the memory interface, and the data, and its related parity information and ECC codes will be stored in the cache. On the other hand, data which is taken from the cache and modified by the CPU during its processing operations is also transferred to the memory interface for ECC encoding. Thus, all data modified by the CPU is also protected, and the modified data, and its related parity information and ECC codes are also stored in the cache.
    Type: Grant
    Filed: October 1, 1990
    Date of Patent: August 3, 1993
    Assignee: Digital Equipment Corporation
    Inventor: Michael A. Callander
  • Patent number: 5231246
    Abstract: An apparatus for joining together two enclosures which both mechanically fastens the enclosures and provides shielding against electromagnetic emissions. A tubular electromagnetic shield formed as an endless loop is secured around the perimeter of an interface opening by a plurality of shield fasteners. At least some fasteners are of a fold-over type which encircles a portion of the shield and secures it to a surface. The apparatus includes fastener/spacer assemblies for joining the enclosures such that they exert a compressive force on the shield which is disposed between them.
    Type: Grant
    Filed: July 14, 1992
    Date of Patent: July 27, 1993
    Assignee: Digital Equipment Corporation
    Inventors: John M. Benson, David M. Alessandrini, Wayne D. Rett
  • Patent number: D338653
    Type: Grant
    Filed: April 8, 1991
    Date of Patent: August 24, 1993
    Assignee: Digital Equipment Corporation
    Inventors: Stuart K. Morgan, Margaret L. Hetfield
  • Patent number: D340035
    Type: Grant
    Filed: October 11, 1991
    Date of Patent: October 5, 1993
    Assignee: Digital Equipment Corporation
    Inventor: Robert T. Faranda