Abstract: An arrangement providing frame buffer memory for an output display by which single buffer and double buffered application programs may be run singly or simultaneously is described. An array of video random access memory sufficient to store data for at least two complete frames is configured in three different ways depending on the applications being run. When only programs designed to run on a single frame buffer are run, the memory is configured as a single frame buffer. When a single program designed to run on double frame buffers is run, the memory is configured as two visible frame buffers. When multiple programs designed to run on double frame buffers are run, the memory is configured into one visible and one invisible frame buffer. Additionally, apparatus for selecting data to be furnished to the display depending on whether the program operates as a single buffered program, a double buffered program, or a plurality of double buffered programs is provided.

Abstract: Embodiments of the present invention provide an improved method and system for securely controlling access to resources in a distributed computer system. One embodiment of the present invention stores and binds a group identification to a target object and then uses membership checking to determine whether a client object which requests access to the target object is a member of a group with access rights to the target object. In this way, the present invention avoids performing costly cryptographic operations in order to verify access rights of requesting objects, as was common in some prior art systems.A second embodiment of the present invention stores and binds a group identification to a target object reference and then passes the target object reference to client objects in the system. Since the target object reference includes a group identification entry, a first client object is able to determine which other clients in the system are members of the identified group.

Abstract: A three-layer BGA package includes a BGA Vss plane disposed between upper and lower BGA package traces, and also includes upper and lower BGA package Vss traces on the outer periphery of the BGA package. Vias electrically and thermally couple the BGA Vss plane to upper and lower BGA package Vss traces. Other vias electrically couple Vdd and IC signals from Vdd and signal traces on the upper and lower surfaces of the BGA package. Solder balls connected to the BGA package lower traces are soldered to matching traces on a system PCB. The periphery Vss traces, vias and solder balls help maintain current flow in the BGA Vss plane. In addition to providing a low impedance current return path (and thus reduced ground bounce and reduced IC signal delay time) for current sunk by an IC within the BGA package, the BGA Vss plane provides heat sinking. A four-layer BGA package further includes a BGA Vdd plane located intermediate the BGA Vss plane and the traces on the lower surface of the BGA package.

Abstract: A selector circuit with symmetry is disclosed. It steers input transition events to one of two outputs according to the value of a data input signal. The selector circuit includes a first flip-flop and a second flip-flop. Depending on the state of a data input, one of the two flip-flops is enabled and the other is disabled. The disabled flip-flop will be in a tristate mode. The enabled flip-flop continues storing its data, and may load the disabled flip-flop with this data. The selector circuit further includes pass gates to couple the outputs of the flip-flops based on the state of the event input.

Abstract: A decoder is used in an end-to-end scalable video delivery system operable over heterogeneous networks. The decoder may software-based and computationally low complexity, or may be implemented inexpensively in ROM hardware. The system utilizes a scalable video compression algorithm based on a Laplacian pyramid decomposition to generate an embedded information stream. At the receiving end, the decoder extracts from the embedded stream different streams at different spatial and temporal resolutions. Decoding a 160.times.120 pixel image involves only decompressing a base layer 160.times.120 pixel image. Decoding a 320.times.240 pixel image involves decompressing and up-sampling (e.g., interpolating) the base layer to yield a 320.times.240 pixel image to which is added error data in a first enhancement layer following its decompression. To obtain a 640.times.480 pixel image, the decoder up-samples the up-sampled 320.times.

Abstract: The present invention discloses a computer-implemented method for testing a software product using a server computer system and a plurality of servant computer systems which are networked together. The method includes the step of providing the server computer system with the software product to be tested and an associated test suite. The test suite being designed to exercise the software product and generate a test suite log indicative of test results obtained from executing the test suite. The server computer system then transmits the software product and the test suite to user-defined servant computer systems such that the software product and test suite is executed on each of the user-defined servant computer systems. A test suite log is then generated on each of the selected servant computer systems and transmitted back to the server computer system.

Abstract: An improved system for database query processing by means of "query decomposition" intercepts database queries prior to processing by a database management system ("DBMS"). The system decomposes at least selected queries to generate multiple subqueries for application, in parallel, to the DBMS, in lieu of the intercepted query. Responses by the DBMS to the subqueries are assembled by the system to generate a final response. The system also provides improved methods and apparatus for storage and retrieval of records from a database utilizing the DBMS's cluster storage and index retrieval facilitates, in combination with a smaller-than-usual hash bucket size.

Abstract: In a client/server computing system, a method and apparatus for efficiently storing entries in a log file during disconnected client operations. An encoder utilizes a log file and a write file table for logging the write operations performed by the client during disconnected operations. The logging method employed by the encoding module logs in the log file only writes associated for different files. The encoding module tracks the status of the entries in the log file with a write file table containing the most recent sequence number associated with a file entry of the log file. Upon reconnection of the client to the server, a decoding module replays the events in the correct chronological order by transferring the file data modified during the period of disconnection in the order dictated by the write file table. A deferred write list is accessed by the decoding module for temporary storage any write operations whose replay should be delayed to preserve the relative order of events.

Abstract: A method and an apparatus for hardware and software interaction in data transfers of shared data structures in memory. The method and apparatus decreases the number of mutex lockings required to prevent conflict between different software attempting to access the same data and keeps the index value for each buffer in use in order to prevent conflicts between buffer replacement and packet arrival. In an exemplary implementation of the method and apparatus of the present invention, a receive hardware of a computer system keeps an index value for each buffer in use. This index value is placed in a completion ring protected by a mutex, and placed in a software queue protected by mutex. The mutexes assure that only one thread will possess a given index at a given time. No mutex locking is required for a buffer table containing software address and related information.

Abstract: A method and structure for testing a circuit with reduced test pattern generation constraints. The circuit includes a first logic circuit coupled to receive input signals from a first flip-flop and a second flip-flop. The first and second flip-flops store part of a test pattern generated to test the circuit. The circuit also includes first and second three state driver (TSD) circuits coupled to receive output signals from the first logic circuit. The output leads of the first and second TSDs are connected to a single input lead of a second logic circuit. The first and second TSDs receive control signals that enable and disable the first and second TSDs. The control signals are provided by the first logic circuit or, alternatively, by a separate decoder. During test operations, the control signals enable the first and second TSDs substantially simultaneously for a predetermined duration.

Abstract: Digital delivery of receipts overcomes many of the problems associated with paper receipts. Digital receipts can be delivered over a properitary or over an open network such as the Internet. They can be uploaded to a smart card. They can be standardized in format to facilitate automated processing. An e-mail address can be incorporated into a bank card or other machine readable and for automatic routing of the receipt to a payor's e-mailbox.

Abstract: A 3-D graphics accelerator which includes a command block with geometry data decompression capabilities and thus includes improved performance over prior art designs. The 3-D graphics accelerator couples to a system bus in the computer system and receives compressed geometry data from the system memory. The 3-D graphics accelerator includes a command block or preprocessor, a plurality of floating point processors or blocks, and one or more draw processors or blocks. The command processor includes a first data path which transmits non-compressed geometry data, and a second data path which receives the compressed geometry data and decompresses the compressed geometry data. In the preferred embodiment, the command processor includes one or more input buffers, a geometry decompression unit, and multiplexer logic. The input buffers couple to the system bus for receiving geometry input data. The geometry input data includes compressed geometry input data and non-compressed geometry input data.

Abstract: A program interpreter for computer programs written in a bytecode language, which uses a restricted set of data type specific bytecodes. The interpreter, prior to executing any bytecode program, executes a bytecode program verifier procedure that verifies the integrity of a specified program by identifying any bytecode instruction that would process data of the wrong type for such a bytecode and any bytecode instruction sequences in the specified program that would cause underflow or overflow of the operand stack. If the program verifier finds any instructions that violate predefined stack usage and data type usage restrictions, execution of the program by the interpreter is prevented. After pre-processing of the program by the verifier, if no program faults were found, the interpreter executes the program without performing operand stack overflow and underflow checks and without performing data type checks on operands stored in operand stack. As a result, program execution speed is greatly improved.

Abstract: A system, method and computer program product for ensuring that a replicated computer database does not encounter a "split brain" problem by replicating the database and requiring a replica quorum wherein at least (50% +1) of the replicas are accessible and in agreement. When a replica quorum in not obtainable, but 50% of the copies of the data are in agreement, an external source, or "mediator", is called upon to provide a deciding vote (+1) to ensure that the data can be trusted.

Abstract: In order to prevent data corruption and inconsistency caused by incorrect assumption regarding a presumably failed node and/or program, a fail-fast timer mechanism enforces deadlines, i.e. enforces timeliness in programs. For example, given a program which needs to ensure a given code segment is executed within a specified deadline, the program arms a fail-fast timer before executing the code segment. After completing the execution of the code segment, the program disarms the fail-fast timer. If the program executes too slowly and the fail-fast timer expires before the fail-fast timer has been disarmed, the entire node is forced to stop very quickly (i.e. the node fails fast). The fail-fast timer of the present invention also triggers if the program exits before disarming a previously armed timeout.

Abstract: A system and method are disclosed that enable a batch lexer to be used to incrementally update a token stream representation of a computer program maintained in an editor as the computer program is being edited. A keystroke executive interprets editing inputs and dispatches editing events to a lexical analyzer. The lexical analyzer converts a range of the tokens likely to be affected to an equivalent old textual stream that preserves whitespace implied by but not represented within the token stream. A new text stream is generated from the old text stream by carrying out the current editing event. I.e., insertion of text is handled by the insertion of the relevant text into the old text stream (now the new stream) and deletion of a character is handled by deleting the appropriate character from the old text stream. The batch lexer is then invoked on the new text stream and as a result returns a new token stream.

Abstract: Embodiments of the present invention provide a computer implemented method and apparatus for processing user defined input on a graphical user interface (GUI). Initially, a first user defined input value is received in a first graphical processing element. This first graphical processing element determines if the first user defined input value is a valid input value. Typically, this is done by comparing the first user defined input value with a set of valid input values. The first graphical processing element and said feedback message are embedded in a second graphical processing element. The second graphical processing element receives a feedback message from the first graphical processing element if the first graphical processing element determines that the first user defined input value is invalid. The second graphical processing element displays the feedback message and the first graphical processing element in a GUI when the first user defined input value is invalid.

Abstract: The invention provides solutions to the problems which are encountered by object oriented systems designers when attempting to implement schemes for object invocation and for argument passing in distributed systems wherein the arguments may be objects, and wherein the system supports a multiplicity of ORB-specific data formats, in ways which do not lock the object oriented base system into methods which may be difficult to change at a later time.

Abstract: A computer system is disclosed including a memory subsystem and a processor subsystem having an external cache and an external mechanism for invalidating cached datablocks in the processor subsystem and for reducing false invalidation operations. The processor subsystem issues a write invalidate message to the memory subsystem that specifies a datablock and that includes an invalidate advisory indication that indicates whether the datablock is present in the external cache. The invalidate advisory indication determines whether the memory subsystem returns an invalidate message to the processor subsystem for the write invalidate operation.

Abstract: A variety of methods and apparatus are taught for providing dynamic distributed file system client authentication. One method for providing dynamic distributed file system client authentication within a distributed file system computing environment includes the steps of receiving an NFS request from an NFS client, determining whether the NFS client has an access status sufficient to perform the NFS request, and performing the NFS request when the NFS client has sufficient access status. In some embodiments, the NFS request includes a file handle representing a given file system available on the server computer system and a file operation to be performed upon the given file system. A server computer in accordance with one embodiment of the present invention is operable to provide dynamic NFS client authentication.