Patents Assigned to Tandem Computer, Inc.
  • Patent number: 6115826
    Abstract: A system for timing intervals in a computer. The system provides an interval timing service for processes running in a computer system. The timing service supports a potentially large number of interval timers by using "timing wheels" that "turn" at different periods. The time base for the fastest turning wheel can be an interrupt event or some other hardware or software control.
    Type: Grant
    Filed: September 15, 1998
    Date of Patent: September 5, 2000
    Assignee: Tandem Computers, Inc.
    Inventor: Joseph D. Kinkade
  • Patent number: 6112079
    Abstract: The system and method of the present invention facilitates an improved Home Location Register (HLR) that includes a fraud protection mediation module for use in a mobile telephone system. The fraud protection mediation module operates in any one of the following situations: (1) a registration notice (REGNOT) is received by the HLR from a Mobile Switching Center (MSC) currently serving a subscriber in a roaming area; (2) a qualification request (QUALREQ) is received by the HLR from a serving MSC for obtaining a subscriber's profile; and (3) the HLR sends a qualification directive to a serving MSC, with the updated or modified profile of the subscriber. By using the improved HLR of the present invention, a carrier may have the HLR bypass the fraud protection processing in areas that support authentication processing to provide convenience to the subscribers so that they do not have to enter their PINs to use their cellular phones.
    Type: Grant
    Filed: January 4, 1999
    Date of Patent: August 29, 2000
    Assignee: Tandem Computers, Inc.
    Inventor: James A. Lamb
  • Patent number: 6085083
    Abstract: The system and method of the present invention facilitates an improved home location register (HLR) that includes a fraud protection mediation module for use in a mobile telephone system. The fraud protection mediation module operates in any one of the following situations: (1) a registration notice (REGNOT) is received by the HLR from a mobile switching center (MSC) currently serving a subscriber in a roaming area; (2) a qualification request (QUALREQ) is received by the HLR from a serving MSC for obtaining a subscriber's profile; and (3) the HLR sends a qualification directive to a serving MSC, with the updated or modified profile of the subscriber. By using the improved HLR of the present invention, a carrier may have the HLR bypass the fraud protection processing in areas that support authentication processing to provide convenience to the subscribers so that they do not have to enter their PINs to use their cellular phones.
    Type: Grant
    Filed: January 11, 1997
    Date of Patent: July 4, 2000
    Assignee: Tandem Computers, Inc.
    Inventor: James A. Lamb
  • Patent number: 6035301
    Abstract: A method and apparatus for providing an OLE automation interface to transactions services is provided. The method and apparatus includes an OLE/TP gateway. The OLE/TP gateway dynamically creates OLE objects that correspond to one or more transaction services. Client programs manipulate the methods and properties included in the OLE objects to perform transactions involving the transaction services. The present invention also includes a visual development environment that allows the user to visually select the type of OLE objects that the OLE/TP gateway makes available to client programs.
    Type: Grant
    Filed: December 18, 1997
    Date of Patent: March 7, 2000
    Assignee: Tandem Computers, Inc.
    Inventors: Frank Siegel, Russel Smith, David J. Cooper, Bill Culman
  • Patent number: 6021405
    Abstract: A system and method for optimizing a database query with improved performance enhancements is herein disclosed. The database query consists of one or more logical expressions. Through the repeated application of one or more rules, the logical expressions are transformed into execution plans. The query optimizer partitions the database query into one or more subproblems with each subproblem consisting of one or more logical expressions. A plan is obtained for each subproblem with the plan for the database query including the plans for each subproblem. The query optimizer is cost-based and uses rules including transformation and implementation rules that are used to perform transformations on the logical expressions in a subproblem in order to produce a plan. The rules are classified into context-free and context-sensitive in order to avoid generating duplicate expressions.
    Type: Grant
    Filed: December 11, 1996
    Date of Patent: February 1, 2000
    Assignee: Tandem Computers, Inc.
    Inventors: Pedro Celis, Diana Shak, Jay Vaishnav, Hansjorg Zeller
  • Patent number: 5914953
    Abstract: A processing system includes multiple processor units and multiple input/output elements communicatively interconnected by a system area network having a plurality of multi-ported router elements. Communication between the system elements uses message packets that contain, among other things, destination information that identifies the intended recipient of the message packet. That destination information is used, at least in part, for routing message packets from a its source to its intended destination. Deadlocks are eliminated by providing each router with information as to which ports cannot be used for re-transmission of a message packet, depending upon which port is receiving that message packet.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: June 22, 1999
    Assignee: Tandem Computers, Inc.
    Inventors: John C. Krause, David J. Garcia, Robert W. Horst, Geoffrey I. Iswandhi, David Paul Sonnier, William Joel Watson, Linda Ellen Zalzala
  • Patent number: 5889530
    Abstract: A system for dynamically graphically presenting a concept of interest related to the operation of a software target sub-system asks the sub-system to include changes in values relevant to the concept of interest in a telemetry stream propagated by the target sub-system. These values are held by receptors and collections of values relevant to the concept of interest are utilized to create renderings indicating characteristics of the concept of interest. A holder is provided for each value and a single value may be used to create different renderings thereby reducing the cost to the target sub-system. Whenever a value change is propagated each collection is notified so that the renderings are updated.
    Type: Grant
    Filed: March 14, 1996
    Date of Patent: March 30, 1999
    Assignee: Tandem Computers, Inc.
    Inventor: Roland Findlay
  • Patent number: 5842204
    Abstract: A method and apparatus for translating source code written in one computer language to source code written in another language wherein translated static fragments are generated in the face of textual inconsistencies. Exactly one target language definition of each source language static fragment is generated and the differences are encapsulated in new parameters.
    Type: Grant
    Filed: November 1, 1994
    Date of Patent: November 24, 1998
    Assignee: Tandem Computers, Inc.
    Inventors: Kristy A. Andrews, Paul Del Vigna, Mark E. Molloy
  • Patent number: 5828569
    Abstract: A method and apparatus for maintaining network connections across a voluntary takeover involving the use of dual processors in an protocol process node running a protocol process application as an intermediary to server and client applications. The protocol process node's primary processor checkpoints data to a backup processor. The data relates to the creation of a network connection between the server and client. Using the checkpointed data, the backup processor can assume the responsibilities of the primary processor in the event of a voluntary takeover of the primary processor.
    Type: Grant
    Filed: May 21, 1997
    Date of Patent: October 27, 1998
    Assignee: Tandem Computers, Inc.
    Inventor: Michael E. Fisher
  • Patent number: 5822747
    Abstract: A system and method for optimizing a database query is herein disclosed. The system consists of a search engine and a database implementor that determines an optimal plan for executing a SQL query. The SQL query is represented as a query tree consisting of a number of nested expressions. The search engine generates a number of plans from which an optimal plan is selected. Plans are generated through the application of a set of rules consisting of implementation and transformation rules. Implementation rules are used to obtain plans. Transformation rules are used to determine equivalent expressions. A plan for the query tree entails finding plans for each expression within the tree where each plan is generated in accordance with a prescribed set of rules. The database implementor selects the set of rules such that more promising plans are generated rather than generating all possible plans.
    Type: Grant
    Filed: August 23, 1996
    Date of Patent: October 13, 1998
    Assignee: Tandem Computers, Inc.
    Inventors: Goetz Graefe, Pedro Celis, Jay Vaishnav, Hansjorg Zeller
  • Patent number: 5819255
    Abstract: A system and method for optimizing a database query with improved performance enhancements is herein disclosed. The database query consists of one or more logical expressions. Through the repeated application of one or more rules, the logical expressions are transformed into physical expressions and in some cases, execution plans that implement the database query. Each expression has associated with it a set of group attributes that specifies its characteristic inputs and outputs and a cost that estimates the computational expense for executing the expression. The group attributes are used to categorize similar expressions into groups that are stored in a search data structure. They are also used to track duplicate expressions. The cost associated with an expression is used to guide the search process to consider those expressions that will produce low cost plans.
    Type: Grant
    Filed: December 27, 1996
    Date of Patent: October 6, 1998
    Assignee: Tandem Computers, Inc.
    Inventors: Pedro Celis, Jay Vaishnav, Hansjorg Zeller
  • Patent number: 5799323
    Abstract: A primary computer system has a database, application programs that modify the local database, and a transaction manager that stores audit records in a local audit trail reflecting those application program modifications to the local database. A plurality of parallel backup systems are used to provide "triple contingency protection" of the data on the primary computer system. However, if the primary system suffers a sudden catastrophic failure, the parallel backup systems will generally be left in inconsistent states. To restart the application programs on one of the backup system, the parallel backup are first synchronized with each other, and then transaction processing is restarted with one of the backup systems as the new primary system, and the other backup systems as the backups to the new primary system.
    Type: Grant
    Filed: January 30, 1997
    Date of Patent: August 25, 1998
    Assignee: Tandem Computers, Inc.
    Inventors: Malcolm Mosher, Jr., Gordon J. Bowring
  • Patent number: 5799322
    Abstract: A primary computer system has a database, application programs that modify the local database, and a transaction manager that stores audit records in a local audit trail reflecting those application program modifications to the local database. A plurality of parallel backup systems are used to provide "triple contingency protection" of the data on the primary computer system. However, if the primary system suffers a sudden catastrophic failure, the parallel backup systems will generally be left in inconsistent states. To restart the application programs on one of the backup system, the parallel backup are first synchronized with each other, and then transaction processing is restarted with one of the backup systems as the new primary system, and the other backup systems as the backups to the new primary system.
    Type: Grant
    Filed: January 30, 1997
    Date of Patent: August 25, 1998
    Assignee: Tandem Computer, Inc.
    Inventor: Malcolm Mosher, Jr.
  • Patent number: 5794252
    Abstract: A local computer system has local database, application programs that modify the local database, an a transaction manager that stores audit records in a local audit trail reflecting those application program modifications to the local database. A remotely located computer system has a backup database. A remote data duplication facility (RDF) is partially located in the local computer system and partially in the remote computer for maintaining virtual synchronization of the backup database with the local database. The RDF includes an extractor process executed by said local computer system, and a receiver process and a plurality of updater processes executed by the remote computer system. The extractor process extracts audit records from a local audit trail and transmits those records to the receiver process. The receiver process distributes the audit records into one or more image trail files that are associated with a particular updater process.
    Type: Grant
    Filed: December 16, 1996
    Date of Patent: August 11, 1998
    Assignee: Tandem Computers, Inc.
    Inventors: Bruce W. Bailey, Malcolm Mosher, Jr.
  • Patent number: 5790868
    Abstract: A distributed computer system having a plurality of end user terminals and a plurality of loosely coupled server computers that share no resources with each other. A multiplicity of user application processes are distributed over the server computers. An Enq table is stored on a first one of the server computers. The Enq table includes Enq records, each representing a locked resource. When any user application process executes an Enq instruction naming a specific resource, if the Enq table does not already contain an Enq record for the specific resource an Enq record is generated and stored in the Enq table representing the specific resource as locked. The Enq record is stored in the same Enq table on the first server computer regardless of which server computer executes the Enq instruction. If the Enq table does already contain an Enq record for the specific resource, execution of the user application process that executed the Enq instruction is suspended.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: August 4, 1998
    Assignee: Tandem Computers, Inc.
    Inventors: Andreas E. Hotea, John S. de Roo, Mark Phillips
  • Patent number: 5764879
    Abstract: A fault tolerant computer system distributes audit trail files containing audit records, across an arbitrary number of disk volumes. After one audit trail file becomes full, audit records are directed toward a next audit trail file stored on a different disk volume. Storage of newly generated audit rotates through the disk volumes in roundrobin fashion. Full audit trail files are eventually archived and their space becomes available again for renaming and storage of newly generated audit records. The number of audit records available for on-line recovery after a failure is not limited to the storage capacity of any single disk volume. Furthermore, there is no contention for disk access between archiving of full audit trail files and storage of newly generated audit records.
    Type: Grant
    Filed: July 29, 1996
    Date of Patent: June 9, 1998
    Assignee: Tandem Computers, Inc.
    Inventors: Michael J. Skarpelos, Robert van der Linden, William J. Carley, James A. Lyon, Matthew C. McCline
  • Patent number: 5745753
    Abstract: A local computer system has a local database, application programs that modify the local database, and a transaction manager that stores audit records in a local audit trail reflecting those application program modifications to the local database. A remotely located computer system has a backup database. A remote data duplication facility (RDF) maintains virtual synchronization of the backup database with the local database. The RDF includes an extractor process executed by the local computer system, and a receiver process and a plurality of updater processes executed by the remote computer system. The extractor process extracts audit records from the local audit trail and transmits those records to the receiver process. The receiver distributes the received audit records to a plurality of image trail files in the remote computer system for processing by updater processes, which initiate redo operations of database modifications denoted in at least a subset of the audit records against the backup database.
    Type: Grant
    Filed: January 24, 1995
    Date of Patent: April 28, 1998
    Assignee: Tandem Computers, Inc.
    Inventor: Malcolm Mosher, Jr.
  • Patent number: 5740433
    Abstract: A local computer system has a local database, application programs that modify the database and a transaction manager that stores audit records in a local audit trail reflecting the application programs' modifications to the local database. A remote computer system has a backup database. A remote data duplication facility (RDF) is distributed in the local computer system and the remote computer for maintaining synchronization of the backup database with the local database. The RDF has an extractor process and a receiver process. The extractor process has multiple updater processes, extracts audit records from the local audit trail and transmits them to the receiver process, which distributes them to the updater processes which in tuna initiate redo operations of database modifications in at least a subset of the audit records against the backup database.
    Type: Grant
    Filed: August 28, 1996
    Date of Patent: April 14, 1998
    Assignee: Tandem Computers, Inc.
    Inventors: Richard W. Carr, Brian Garrard, Malcolm Mosher, Jr.
  • Patent number: 5717911
    Abstract: An SQL program executor and an SOL compiler both include options for avoiding recompilations of execution plans whenever the runtime object and the compile time object referenced by an execution plan meet predefined schema similarity criteria. Thus, recompilation is sometimes avoided even though the compile time object has been altered or the run time object is not the same object as the compile time object. To enable late binding, schema information is stored in each execution plan for each object to be accessed by the execution plan. The stored schema information is a subset of the full object schema, and includes information about all the aspects of the objects to be accessed which must remain unchanged in order for the execution plan to be operable. While executing a compiled program, the SQL executor avoids recompilations of execution plans whenever the runtime object and the compile time object referenced by an execution plan meet predefined schema similarity criteria.
    Type: Grant
    Filed: January 23, 1995
    Date of Patent: February 10, 1998
    Assignee: Tandem Computers, Inc.
    Inventors: Louise M. Madrid, Richard A. Meier, Franco Putzolu, Sunil Sharma, Thomas J. O'Shea, James H. Troisi, Hansjorg Zeller, Gary M. Gilbert, Donald S. Maier, Elizabeth G. Davis, Pedro Celis
  • Patent number: 5687372
    Abstract: In summary, the present invention is a distributed computer system having a plurality of end user terminals and a plurality of loosely coupled server computers that share no resources with each other. A multiplicity of user application processes are distributed over the server computers. A communication interface or router transmits data between the end user terminals and a transaction router process, which executes on one of the server computers. The transaction router process initiates execution of transactions by ones of the user application processes based on data received from the end user terminals. A link manager process selects application processes to execute the applications based on computational load distribution criteria, so as to distribute computational load as evenly as possible over the server computers, thereby maximizing the throughput and responsiveness of the system.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: November 11, 1997
    Assignee: Tandem Computers, Inc.
    Inventors: Andreas E. Hotea, John S. de Roo, Mark Phillips, David G. Velasco