Patents Assigned to Digital Equipment
  • Patent number: 5978212
    Abstract: A locking member formed of resilient material for locking a disk drive within a computer enclosure includes a first cantilevered beam portion positioned along a first side of the disk drive. A first locking protrusion is positioned on the first cantilevered beam portion and is capable of engaging with the enclosure for locking the disk drive therein. A handle portion extends from the cantilevered beam portion for resiliently bending the first cantilevered beam portion inwardly to disengage the first locking protrusion from the enclosure.
    Type: Grant
    Filed: February 28, 1997
    Date of Patent: November 2, 1999
    Assignee: Digital Equipment Corporation
    Inventors: Steven G. Boulay, Stanley W. Stefanick, Jeffrey E. Gravel
  • Patent number: 5978892
    Abstract: A new virtual memory system is disclosed having a virtual address space including a gap of inaccessible virtual addresses within the virtual address space. A new virtual memory allocation routine is disclosed providing a starting address of accessible virtual addresses allocated to a currently executing process in a response to a request. The accessible virtual addresses are virtually contiguous, and include no addresses from within the gap of inaccessible virtual addresses. A new virtual memory deallocation routine is further disclosed providing deallocation of ranges of virtual addresses which may or may not include addresses within the inaccessible gap.
    Type: Grant
    Filed: May 3, 1996
    Date of Patent: November 2, 1999
    Assignee: Digital Equipment Corporation
    Inventors: Karen Lee Noel, Michael Seward Harvey
  • Patent number: 5978571
    Abstract: A method for use in the design or implementation of a synchronous circuit having nodes interconnecting logic functions and in which the nodes assume logic values in successive clocked phases of a logical cycle. For a phase for a node connected to an output of a logic function, a determination is made (and stored) of which nodes, connected to inputs of the logic function, have and do not have timing behaviors in that phase which are needed in order to determine the logic value assumed by the output node in that phase.
    Type: Grant
    Filed: May 12, 1997
    Date of Patent: November 2, 1999
    Assignee: Digital Equipment Corporation
    Inventor: William John Grundmann
  • Patent number: 5978118
    Abstract: Apparatus for communication in a fiberoptic LAN includes a first transmitter of an electromagnetic wave of a first wavelength, a second detector of an electromagnetic wave of a second wavelength, and an optical coupler coupled to the first transmitter, the second detector, and the fiberoptic LAN.
    Type: Grant
    Filed: February 4, 1997
    Date of Patent: November 2, 1999
    Assignee: Digital Equipment Corporation
    Inventor: Paul A. Flaherty
  • Patent number: 5974506
    Abstract: A cache memory system is enabled into one of a plurality of cache modes in a cache memory system in a computer. The cache memory system has a first controller and two cache memories, the cache memories are partitioned into quadrants with two quadrants in each cache memory. A cache mode detector in the first controller detects a mirror cache mode set for the cache memory system. An address enabler in the first controller enables access to first pair of quadrants, one quadrant in each cache memory, in response to detection of a mirror cache mode. A second controller follows the cache mode set by the cache mode detector and has an address enabler. The address enabler in the second controller enables access to both quadrants in one cache memory in a non-mirror cache mode, and enables the access to a second pair of quadrants, one quadrant in each cache memory, in response to detection of a mirror cache mode by said cache mode detector.
    Type: Grant
    Filed: June 28, 1996
    Date of Patent: October 26, 1999
    Assignee: Digital Equipment Corporation
    Inventors: Stephen J. Sicola, Wayne H. Umland, Thomas F. Fava, Clark E. Lubbers, Susan G. Elkington
  • Patent number: 5974455
    Abstract: A Web crawler system and method for quickly fetching and analyzing Web pages on the World Wide Web includes a hash table stored in random access memory (RAM) and a sequential Web information disk file. For every Web page known to the system, the Web crawler system stores an entry in the sequential disk file as well as a smaller entry in the hash table. The hash table entry includes a fingerprint value, a fetched flag that is set true only if the corresponding Web page has been successfully fetched, and a file location indicator that indicates where the corresponding entry is stored in the sequential disk file. Each sequential disk file entry includes the URL of a corresponding Web page, plus fetch status information concerning that Web page. All accesses to the Web information disk file are made sequentially via an input buffer such that a large number of entries from the sequential disk file are moved into the input buffer as single I/O operation.
    Type: Grant
    Filed: December 13, 1995
    Date of Patent: October 26, 1999
    Assignee: Digital Equipment Corporation
    Inventor: Louis M. Monier
  • Patent number: 5974481
    Abstract: Strings, such as Web pages or other documents, are fingerprinted in order to detect substantially similar strings, so as to avoid processing duplicate strings. At the same time determine a computerized method estimates the probability that a collision among fingerprints of dissimilar strings. As fingerprints are generated for strings presented for processing, when the fingerprint of a string is determined not to be identical to any fingerprint in a set of stored fingerprints, the new fingerprint is masked and the unmasked portion of the fingerprint is compared with a corresponding portion of the fingerprints in the stored set. Information is recorded regarding the number of matching masked fingerprints.
    Type: Grant
    Filed: September 15, 1997
    Date of Patent: October 26, 1999
    Assignee: Digital Equipment Corporation
    Inventor: Andrei Zary Broder
  • Patent number: 5970497
    Abstract: A computer implemented method indexes duplicate information stored in records having different unique addresses in a database. A fingerprint is generated for each record, the fingerprint is a singular value derived from all of the information of the record. The fingerprint is stored in the index as a unique fingerprint if the fingerprint is different than a previously stored fingerprint of the index. A reference to the unique address of the record is stored with the fingerprint. If the fingerprint is identical to the previously stored fingerprint, then store the reference to the address of the record with the previously stored fingerprint.
    Type: Grant
    Filed: April 27, 1998
    Date of Patent: October 19, 1999
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5968153
    Abstract: A method and apparatus for maximizing the performance of DMA transfers over a PCI.TM. bus are provided which includes a Per-Channel Retry count, Double Buffer Management, Wait Enable functionality, Back Up register functionality, Gather/Scatter mapping, a method for minimization of PIO writes, Read Semaphore functionality, a method for servicing of DMA transfers during FMU latency periods, Valid bit functionality, high and low water thresholds, and re-usable page tables.
    Type: Grant
    Filed: October 13, 1998
    Date of Patent: October 19, 1999
    Assignee: Digital Equipment Corporation
    Inventors: William R. Wheeler, Matthew James Adiletta, Samuel Ho, Debra Bernstein, Gilbert M. Wolrich
  • Patent number: 5966735
    Abstract: A new system and method for outswapping a process is disclosed. The new system forms one or more working set list chains (also referred to as "page table chains") during the outswap process. The new system then conveniently locates and outswaps a number of page table pages of the process to be outswapped by traversing the working set list chains. In a preferred embodiment, the forming of each working set list chain is performed while traversing a working set list during outswapping of a number of body pages of a process. Each working set list entry potentially describes a page of virtual memory in use by the process to be outswapped. In a further aspect of the disclosed system, traversing the working set list of the process to be outswapped includes determining whether each one of the working set list entries indicates a private page table page. If an entry in the working set list indicates a private page table page, the present system adds a link to a working set list chain.
    Type: Grant
    Filed: November 22, 1996
    Date of Patent: October 12, 1999
    Assignee: Digital Equipment Corporation
    Inventors: Karen Lee Noel, Michael Seward Harvey, Thomas Robert Benson
  • Patent number: 5966539
    Abstract: A computer system is directed to convert a program written as a plurality of high level source code modules into corresponding machine executable code. The source code modules are compiled into an object code module, and the object code modules are translated into a single linked code module in the form of a register translation language and logical symbol table compatible with a plurality of computer system hardware architectures. The source code program structures are recovered from the linked code module, and the linked code module is partitioned into a plurality of procedure, and instructions of each of the procedures grouped into basic blocks. A procedure flow graph is constructed for each of the procedures, and a program call graph is constructed for the linked code module. The linked code module is modified by eliminating dead code and moving loop-invariant code from loops.
    Type: Grant
    Filed: November 3, 1997
    Date of Patent: October 12, 1999
    Assignee: Digital Equipment Corporation
    Inventor: Amitabh Srivastava
  • Patent number: 5964867
    Abstract: A method is provided for optimizing a program by inserting memory prefetch operations in the program executing in a computer system. The computer system includes a processor and a memory. Latencies of instructions of the program are measured by hardware while the instructions are processed by a pipeline of the processor. Memory prefetch instructions are automatically inserted in the program based on the measured latencies to optimize execution of the program. The latencies measure the time from when a load instructions issues a request for data to the memory until the data are available in the processor. A program optimizer uses the measured latencies to estimate the number of cycles that elapse before data of a memory operation are available.
    Type: Grant
    Filed: November 26, 1997
    Date of Patent: October 12, 1999
    Assignee: Digital Equipment Corporation
    Inventors: Jennifer-Ann M. Anderson, Jeffrey Dean, James E. Hicks, Carl A. Waldspurger, William E. Weihl
  • Patent number: 5966292
    Abstract: In a modular tower building block system for containing computing system devices, a power bus is incorporated into the modular blocks of the building block system by using a printed circuit board to carry the power bus in each modular block. The printed circuit board is mounted and positioned in each modular block to electrically connect with a printed circuit board in a next adjacent modular block when two modular blocks are stacked on each other. Also, there are a plurality of three-phase power buses on the printed circuit boards and only one phase of each power bus is distributed from each modular block. The printed circuit board is precisely located in each modular block at a predetermined position. Alignment pins and receivers provide alignment between stacked modular blocks to precisely position one modular block to the other modular block.
    Type: Grant
    Filed: June 30, 1997
    Date of Patent: October 12, 1999
    Assignee: Digital Equipment Corporation
    Inventors: Mark Frederick Amberg, Thomas Alvin McKoon, Dwayne Howard Swanson
  • Patent number: 5966710
    Abstract: A system for locating stored information using an index includes a memory and processor. The memory stores an index which includes a plurality of index entries. Each of the index entries corresponds to a respective one of a plurality of terms associated with the stored information and has one or more location identifiers. Each of the location identifiers represents a location within the information at which the corresponding term is associated with the information. The processor searches the stored index to identify the location identifiers of at least two index entries which correspond to terms of interest. The processor also determines the locations within the information which are represented by the identified location identifiers and at which the terms of interest have a relationship as indicated by a particular operator (e.g. "and").
    Type: Grant
    Filed: September 9, 1998
    Date of Patent: October 12, 1999
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5966703
    Abstract: In a computer implemented method, a plurality of records are stored in a database at unique record addresses. The information of each record is parsed into a set of individual words where each word represents a portion of the information of a particular record. A unique sequential location is assigned to each word so that the location of a first word of a next record sequentially follows the location of a last word of a previous record. Pairs are formed from the words and their assigned location. For attributes common to a particular record, generate a record metaword, and assign the location of the last word of the record to the metaword. For attributes common to subsets of words, generate a first and second field metaword, and assign the location of the first and last word of the subset to the first and second field metaword to form pairs.
    Type: Grant
    Filed: April 3, 1998
    Date of Patent: October 12, 1999
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5963972
    Abstract: In a computer implemented method, instructions of a program are mapped into a cache memory of a computer system. The cache memory is partitioned into a plurality fixed size lines for the convenience of accessing the instructions. Each block is assigned a different identification, for example a unique color. The program is partitioned into a plurality of instruction units, for example procedures or basic blocks. A flow graph is generated for the program. In the graph, nodes represent the instructions units, and edges directly connect nodes that have an execution relationship. Instruction units of directly connected nodes are mapped into blocks having different identifications or colors. An unavailable-set of identifications is maintained for each node.
    Type: Grant
    Filed: February 24, 1997
    Date of Patent: October 5, 1999
    Assignee: Digital Equipment Corporation
    Inventors: Bradley Gene Calder, Amir Hooshang Hashemi, David Richard Kaeli
  • Patent number: 5963954
    Abstract: A method for mapping a plurality of index entries in an index of a database includes parsing one or more records into elements, allocating each of the elements to one of a plurality of element groupings, and storing a representation of each of the elements in an index in conjunction with representations of other of the elements within its element grouping.
    Type: Grant
    Filed: July 28, 1998
    Date of Patent: October 5, 1999
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5963556
    Abstract: A network device for interconnecting computer networks, the device including a bridge having a plurality of ports through which network communications pass to and from the bridge, the bridge also including a first interface enabling a user to partition the plurality of bridge ports into a plurality of groups, wherein each group represents a different virtual network, wherein the bridge treats all ports within a given group as part of the virtual network corresponding to that group and the bridge isolates said virtual networks from each other, whereby any communications received at a first port of the bridge are directly sent by the bridge to another bridge port only if the other bridge port and the first bridge port are part of the same group.
    Type: Grant
    Filed: October 22, 1996
    Date of Patent: October 5, 1999
    Assignee: Digital Equipment Corporation
    Inventors: George Varghese, John Bassett, Robert Eugene Thomas, Peter Higginson, Graham Cobb, Barry A. Spinney, Robert Simcoe
  • Patent number: 5963740
    Abstract: A program for monitoring computer system performance includes a collection of source code modules in the form of a high level language. Each of the source code modules is compiled into a corresponding object code module. The object code modules are assembled into machine dependent code. The machine code is translated into a program module in the form of a machine independent register translation language. The program module is partitioned into basic program components. The basic program components include procedures, basic blocks within procedures, and instructions within basic blocks. Fundamental instrumentation routines identify, locate, and modify specific program components to be monitored. The modified basic program components are converted to an instrumented machine executable code to be executed in the computer system so that performance data can be collected while the program is executing in the computer.
    Type: Grant
    Filed: November 21, 1997
    Date of Patent: October 5, 1999
    Assignee: Digital Equipment Corporation
    Inventors: Amitabh Srivastava, Robert Alan Eustace
  • Patent number: 5960383
    Abstract: A document condensation method and apparatus produce a document synopsis are provided in which automatic indexing techniques are used to analyze an input document to determine a list of words and phrases characteristic of the subject matter of the document. Sections of the document are compared to the list of characteristic words and phrases to determine which sections of the document are most like the overall document in view of subject matter. A predetermined number of sections determined to be most similar to the overall document in content are provided as a condensed version of the whole document.
    Type: Grant
    Filed: February 25, 1997
    Date of Patent: September 28, 1999
    Assignee: Digital Equipment Corporation
    Inventor: Robert John Fleischer