Patents by Inventor W. Hugh Durdan

W. Hugh Durdan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5625802
    Abstract: In a computer system, a mother-board is used to physically connect processor, memory, and input/output modules. The mother-board includes an adaptable processor bus for connecting the processor and memory modules, and an input/output bus for connecting the input/output modules, the processor and input/output bus are decoupled for communicating. A processor module including a bridge is used to coupled the processor and input/output buses, and to adapt the processor bus to a particular processor architectures.
    Type: Grant
    Filed: December 12, 1994
    Date of Patent: April 29, 1997
    Assignee: Digital Equipment Corporation
    Inventors: Hoe T. Cho, Maw Z. Jau, W. Hugh Durdan
  • Patent number: 5579504
    Abstract: Multi-processor systems are often implemented using a common system bus as the communication mechanism between CPU, memory, and I/O adapters. It is also common to include features on each CPU module, such as cache memory, that enhance the performance of the execution of instructions in the CPU. Many architectures require that the hardware employ a mechanism by which the data in the individual CPU cache memories is kept consistent with data in main memory and with data in other cache memories. One such method involves each CPU monitoring transactions on the system bus, and taking appropriate action when a transaction appears on the bus which would render data in the CPU's cache incoherent. If the CPU uses queues to hold records of incoming transaction information until it can service them, the bus interface must guarantee that the queued items are processed by the cache in the correct order. If this is not done, certain types of shared data protocols fail to operate correctly.
    Type: Grant
    Filed: March 17, 1995
    Date of Patent: November 26, 1996
    Assignee: Digital Equipment Corporation
    Inventors: Michael A. Callander, G. Michael Uhler, W. Hugh Durdan
  • Patent number: 5058006
    Abstract: An apparatus which filters the number of invalidates to be propagated onto a private processor bus is provided. This is desirable so that the processor bus is not overloaded with invalidate requests. The present invention describes a method of filtering the number of invalidates to be propagated to each processor. A memory interface filters the invalidates by using a second private bus, the invalidate bus, which communicates with the cache controller. The cache controller can tell the memory interface whether data corresponding to the address on the invalidate bus is resident in the private cache memory of that processor. In this way, the memory interface only has to request the private processor bus when necessary, in order to perform the invalidate.
    Type: Grant
    Filed: June 27, 1988
    Date of Patent: October 15, 1991
    Assignee: Digital Equipment Corporation
    Inventors: W. Hugh Durdan, Rebecca L. Stamm, G. Michael Uhler
  • Patent number: 4897779
    Abstract: A protocol for transferring instructions between asynchronous processors in a computer system is provided. Each instruction transfer requires the transfer of an opcode and a variable number of operands. The transfer is accomplished via a bus which interconnects the processors. The opcode and operands are assembled in a buffer in the sending processor and then transferred to the receiving processor in reverse order, i.e., operands first and opcode last. The receiving processor does not acknowledge any of the transfers until it receives the opcode which is always sent last. Upon receipt of the opcode, the receiving processor knows the instruction transfer is complete and sends the acknowledge signal immediately thereafter.
    Type: Grant
    Filed: July 20, 1988
    Date of Patent: January 30, 1990
    Assignee: Digital Equipment Corporation
    Inventors: Robert Dickson, W. Hugh Durdan, George M. Uhler