Patents by Inventor Michael Burrows

Michael Burrows 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: 5765149
    Abstract: There is provided an information processing system in which files on plural file servers having different file management manners can be efficiently accessed by a single client program, a control method for the information processing system, and a storage medium for storing programs for performing the control. A gateway program 20 is provided on a first server information processing device 120, and an agent program 30 which is operated in conformity with the gateway program 20 is provided on a second server information processing device 130, whereby a copy of the directory structure of files on the second server information processing device is created on the first server information processing device 120. In addition, at the time when the copy is created, data in a file are not copied, and the data copy is performed only when the file is opened by an application program 8a of a client information processing device 110.
    Type: Grant
    Filed: August 9, 1996
    Date of Patent: June 9, 1998
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5765150
    Abstract: A computer implemented method selectively searches an index of a database according to scores assigned to records of the database located during the searching. The records of the database are index by storing index entries in a memory. Each index entry includes a word entry representing a unique portion of information of the database and one or more location entries indicating where the unique portion of information represented by the word entry occurs in the records of the database. A weight is assigned to each index entry according to a relative frequency of occurrence of the portion of information in the database. The index is sequentially searched to locate records qualified by a query having terms and operators. The terms correspond to index entries. The located records are scored according to the number of times portions of information corresponding to the terms of the query occur in the records and their associated weights.
    Type: Grant
    Filed: August 9, 1996
    Date of Patent: June 9, 1998
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5765168
    Abstract: A computer implemented method maintains an index of a database. The database stores information as a plurality of records. Batches of records are indexed by storing index entries in a memory. Each index entry includes a word entry for each unique portion of information of the database, and one or more location entries pointing at occurrences of the portions of information. The index entries are organized according to a collating order of the word entries. The location entries are stored sequentially for each word entry. The index entries are organized into a plurality of tiers of files. There is one tier of files for each batch of records indexed. A merged tier of files is periodically produced by merging a subsequently produced tier of files with a previously produced tier of files. The index entries of the merged tier of files are a logical union of the index entries of the subsequently and previous produced tiers of files.
    Type: Grant
    Filed: August 9, 1996
    Date of Patent: June 9, 1998
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5765158
    Abstract: In a computer implemented method, a summary index data structure is generated from a data structure which indexes information stored in a database. Compressed word entries are written to a compressed index data structure. The word entries are written according to a collating order of the words which represent the unique portions of information of the database. Compressed location entries for each word entry are also written to the compressed index data structure immediately following each word entry. Each location entry indicates instances of the associated unique portions of the information represented by the words. While writing the word and location entries to the compressed index data structure, periodically sampling the location entries to generated summary entries. Each summary entry including an encoding of a last word entry written, an encoding of a last location entry written. Each summary entry also includes a pointer to the next entry following the sampled location entry.
    Type: Grant
    Filed: August 9, 1996
    Date of Patent: June 9, 1998
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5745898
    Abstract: A computer implemented method for generating a compressed index of information. The information is stored as a plurality of records in a database. Indexable portions of information are sequentially parsed to generate words and metawords. The words represent the portions, and the metawords represent attributes of the portions. A location is sequentially assigned to each word and metaword in the order that the portions are parsed to form pairs. The pairs are sorted first according to the words and metawords, and second according to the locations. Index entries are written to a memory for each unique word and metaword. Each index entry includes a word entry or a metaword entry, and one or more location entries. The word and metaword entries use a prefix encoding which indicates the number of bytes that the unique word or metaword of a next index entry has in common with the unique word or metaword of a previous index entry. The location entries use a delta value encoding.
    Type: Grant
    Filed: August 9, 1996
    Date of Patent: April 28, 1998
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5745890
    Abstract: A computer implemented method performs constrained searching of an index of a database. The information of the database is stored as a plurality of records. A unique location is assigned to each indexable portion of information of the database. Index entries are written to a memory where each index entry includes a word entry representing a unique indexable portion of information, and one or more location entries for each occurrence of the unique indexable portion information. The index entries are sorted according to a collating order of the word entries, and sequentially according to the location entries of each index entry. A query is parsed to generate a first term and a second term related by an AND logical operator, the AND operator requires that a first index entry corresponding to the first term and a second index entry corresponding to the second term both have locations in the same record to satisfy a query.
    Type: Grant
    Filed: August 9, 1996
    Date of Patent: April 28, 1998
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5745899
    Abstract: An indexing method is provided for a database storing information as records at unique addresses. Pairs are generated for each record, each pair includes a word representing a portion of the information of the record and an associated location. The locations are assigned sequentially as the information is parsed into words. Pairs are also generated for attributes common to each record. In this case, each pair includes a metaword representing the attribute and the location of the last word of the record. Furthermore, two pairs are generated for one or more immediately adjacent words having a common attribute. Here, each pair includes the metaword representing the attribute. The location associated with the first of two pairs is the location of the first adjacent word, and the location of the second pair is the location the last adjacent word. The pairs are sorted first according to the words and metawords, and second according to the location assigned to the words.
    Type: Grant
    Filed: August 9, 1996
    Date of Patent: April 28, 1998
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5745900
    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: August 9, 1996
    Date of Patent: April 28, 1998
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5745894
    Abstract: A method indexes a database so that records including literal values, and numeric values within a specified range can be located. The range is selected from an interval of values. Each record of the database is indexed by storing index entries in a memory. Each index entry includes a literal word entry representing a unique portion of information of the database, and one or more numeric location entries indicating occurrences of the portion of information. A plurality of sets of subintervals are generated from the numeric interval of values. Each set of subintervals includes all of the values of the interval. A first set includes one subinterval for each value of the interval, and each next set includes one interval for a group of adjacent subintervals of a previous set. The subinterval of the last set is the entire interval of numeric values. Each subinterval is represented by a unique literal which can be indexed as a word entry in the index.
    Type: Grant
    Filed: August 9, 1996
    Date of Patent: April 28, 1998
    Assignee: Digital Equipment Corporation
    Inventors: Michael Burrows, Andrew L. Hisgen
  • Patent number: 5745889
    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: August 9, 1996
    Date of Patent: April 28, 1998
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5724033
    Abstract: In a computer implemented method for encoding digital values that are arranged in a successively increasing order, a delta value is determined for each pair of immediately successive values. The delta values are the differences between the pair of immediately successive values. For each delta value which can be encoded as a single byte, a logical zero is stored in the least significant bit of the single byte, and the delta value is stored in the most significant bits of the single byte. Otherwise, for each delta value which must be encoded as a plurality of bytes, a logical one is stored in the least significant bit of the first byte of the plurality of bytes, and a first portion of the delta value is stored in the most significant bits of the first byte. In this case, a logical zero is stored in the most significant bit of the next byte, and a next portion of the delta value is stored in the least significant bits of the next byte.
    Type: Grant
    Filed: August 9, 1996
    Date of Patent: March 3, 1998
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5710724
    Abstract: In a computer system, an instrumented program associated with a first paging table is stored in a memory. The memory also stores an instrumented version of the uninstrumented program associated with a second paging table. The instructions of the uninstrumented and instrumented programs are stored at identical relative addresses. The instrumented programs also includes one word instrumentation points and instrumentation routines to monitor the performance of the computer system. Activating the first paging table causes the uninstrumented program to execute, and activating, in response to a single, the second paging table causes the instrumented program to execute. The instrumentation points cause execution flow to be routed through a gap between word aligned procedures of the program to a routing table, and then instrumentation routines. The gap includes instructions which randomly distributes the execution flow through the routing table.
    Type: Grant
    Filed: April 20, 1995
    Date of Patent: January 20, 1998
    Assignee: Digital Equipment Corp.
    Inventor: Michael Burrows
  • Patent number: 5303302
    Abstract: A network controller receives encrypted data packets in the form of interleaved streams of cells, and stores the received cells in a buffer until the end of each packet is received, at which time the complete packet is decrypted, error checked, and then transmitted to a host computer. The network controller's buffer includes a data storage array in which data packets are stored as linked lists, and a packet directory having a entry for each data packet stored in the buffer. Each directory entry contains a pointer to the first and last location in the buffer where a corresponding data packet is stored, as well as status information for the data packet. When free space in the network controller's buffer falls below a specified threshold, the network controller transmits selected partial packets to the host computer without decrypting or error checking, and also stores in its packet directory entry for each transmitted partial packet a "partial transfer" status flag.
    Type: Grant
    Filed: June 18, 1992
    Date of Patent: April 12, 1994
    Assignee: Digital Equipment Corporation
    Inventor: Michael Burrows
  • Patent number: 5268962
    Abstract: In a computer network, each pair of host computers that need to exchange data packets establish a single host-to-host encryption/decryption key. Then, whenever one host computer sends a data packet to the other host computer, it first forms a predefined logical combination of the established host-to-host key and the destination buffer index to which the data packet is being sent, and then uses the resulting value to encrypt the secure portions of the data packet. The destination buffer index is included in the data packet's header, which is not encrypted. When the receiving host computer receives the encrypted data packet, it reads the destination buffer index from the packet header, forms the same predefined logical combination of the established host-to-host key and the destination buffer index to generate a decryption key, and uses the computed decryption key to decrypt the secure portions of the received data packet.
    Type: Grant
    Filed: July 21, 1992
    Date of Patent: December 7, 1993
    Assignee: Digital Equipment Corporation
    Inventors: Martin Abadi, Michael Burrows, Butler Lampson
  • Patent number: 5173939
    Abstract: A distributed computer system has a number of computers coupled thereto at distinct nodes and a naming service with a membership table that defines a list of assumptions concerning which principals in the system are stronger than other principals, and which roles adopted by principals are stronger than other roles. Each object in the system has an access control list (ACL) having a list of entries. Each entry is either a simple principal or a compound principal. The set of allowed compound principals is limited to a predefined set of allowed combinations of simple principals, roles, delegations and conjunctions in accordance with a defined hierarchical ordering of the conjunction, delegation and role portions of each compound principal. The assumptions in the membership table reduce the number of entries needed in an ACL by allowing an entry to state only the weakest principals and roles that are to be allowed access.
    Type: Grant
    Filed: October 28, 1991
    Date of Patent: December 22, 1992
    Assignee: Digital Equipment Corporation
    Inventors: Martin Abadi, Michael Burrows, Edward P. Wobber