Abstract: A method, system and program for supporting a dynamic bind between a derived class and its parent class. A processor provides for the registration of class objects and dynamic binding of derived class objects to their parent class objects based on the registration mechanism. The SOM object model removes static references to class objects by having all the parent class information available at runtime through the parent class object. Thus, when the derived class implementation needs information about the size of the parent class state data structure, the addresses of the parent class method procedures, or access to the parent class method procedure table the appropriate information is retrieved from the parent class object.

Abstract: Communicating the failure of master process controlling one or more shared resources to all processes sharing the resources. A shared resource control file is established that contains the identities of all sharing processes. Master process failure triggers a race to establish exclusive access over the shared control file. The new master reads shadow address data from the old shared control file, marks it as invalid and establishes a new control file based on renewed registrations from the sharing processes. The master process maintains the sharing process list as process begin and end sharing.

Abstract: A system and method for asynchronously processing SQL language statements in a database management system. A process assigns a unique database handle to each requested connection between an application program and a database, Each application can be concurrently connected to multiple databases. Databases are alternately activated for synchronous or asynchronous processing using the database handle. Following an asynchronous connection, SQL statements are dispatched for asynchronous processing. The application program dispatches an asynchronous statement, performs other processing and then periodically polls the database system to determine whether the statement has completed processing. SQL statement dispatch for synchronous processing performs like current synchronous SQL language systems by waiting for completion of SQL statement processing before continuing.

Abstract: Disclosed is a support architecture that facilitates use of display device drivers containing a minimum of hardware-specific software code. A driver need support only a relatively few common functions, which act as building blocks for the larger, more complex operations typically requested by graphics engines. In order to mediate between the limited-instruction-set device driver and the various higher-level graphics engines, the invention includes a series of translation modules that simplify engine-originated instructions into simpler graphic components. A video manager supervises routing of instructions to the specific drivers they designate, and serializes access to hardware components so that graphic commands execute atomically (i.e., without interruption).

Abstract: A method and apparatus are disclosed for providing exchange of data between a peripheral device having a paging mechanism and an application operating in a virtual machine which includes a page directory for exclusive use by the paging mechanism of the peripheral device. The virtual machine is running on a data processing system and preferably contains a block of memory which is divided into various sections of memory. The page directory is provided to the paging mechanism of the peripheral device when the application requires the use of the peripheral device. A section of memory is selectively locked down in response to the section of memory being utilized by the application. Additionally, the page directory is updated with an entry which identifies the section of memory that is locked down. Memory may also be locked down in order to permit the peripheral device to access that section of memory.

Abstract: A method and system of inserting a floating code hook at a proper position within a program's code having unknown length is provided. The method comprises the steps of estimating an insertion point for a code hook in a computer program loaded in a computer's memory and determining whether expected code is located at the estimated insertion point. If the expected code is located at the estimated insertion point, the method inserts the code hook into the program code at the insertion point. If the expected code is not located at the estimated insertion point, the method moves the estimated insertion point a predetermined number of bytes from the estimated insertion point to a new estimated insertion point, and again determines whether expected code is located at the estimated insertion point. This process continues until the proper insertion point is located, and the floating code hook is inserted.

Abstract: A graphical user interface is provided which can create a predicate for searching for data using only mouse operations on the desktop, and apply the predicate to a database system containing objects to be searched. The user can identify a primitive predicate by inputting search items (that is, file attributes) on the desktop, and can create a logical operation expression for identifying search conditions by displaying a composite predicate representing a logical operator as a folder, and by dragging and dropping an icon representing the predicate on that folder. The logical operation expression can be hierarchically organized and stored. Moreover, a predicate can be displayed on the desktop on a desired hierarchical level by opening or closing an icon for each composite predicate from an icon to a folder, or a folder to an icon.

Abstract: Disclosed are apparatus and methods for synchronized interleaving of multimedia data arriving from distinct sources. The invention independently buffers the incoming data streams and determines the amount of presentation time associated with each data element or byte of each data stream. The invention then draws data from the buffers at varying rates that reflect these differences, continuously presenting the withdrawn data to an interleaving module at data-streaming rates that reflect equivalent presentation-time rates. The invention also includes means for disabling synchronization when one type of data is streamed at a particularly high or low rate, resulting in buffer overload (with either the high-rate data or all data other than that transferred at the low rate).

Abstract: The present invention provides an apparatus for displaying an image of an object, as illuminated by a light source, on a display within a computer graphics display system. The image is graphically represented by a mesh of polygons and each polygon within the mesh has a surface defined by a set of vertices. The vertices define the surface of the polygon. The apparatus includes a processor, such as a rasterizer, that is responsive to each set of vertices for rendering each surface within the mesh of polygons in response to ambient lighting to produce a number of initially rendered surfaces within the mesh of polygons. Phong shading is utilized by the present invention. The processor produces a specular highlight contribution for each surface within the mesh of polygons utilizing a halfway vector, pointing from each surface to a direction halfway between a light vector and a vector pointing towards a viewpoint, associated with a vector normal to each surface.

Abstract: A method and system for optimizing branch prediction in an executable computer program compiled for execution on a pipelined processor that employs branch prediction. The source program is compiled and, in one embodiment, instrumented to collect branch selection statistics. The compiled program is run and statistics collected using the instrumentation or a standard trace program. The branch statistics are used to modify the executable program to cause branch prediction to be correct a majority of the time for the workload against which the program was run. In a computer system having a branch prediction bit, that bit is set or cleared to cause correct branch prediction a majority of the time.

Abstract: An apparatus and method in which an operator can input a three-dimensional (3D) graphics to a graphic system by performing an operation that is as if he were sketching on a paper surface. A line segment of two-dimensional (2D) data is input through an input device such as a mouse, and is then temporarily stored in a storage device as well as being displayed on a 2D display screen. The line segment of 2D data is converted to 3D data when it obtains information in the depth direction based on its relationship to another line segment that constitutes a 3D graphics and has 3D data already. 3D data of line segments that have that data in addition to 2D data are stored in a storage device, and are projected by a projection conversion circuit onto a 2D projection plane that has been set by a visual field input device, so as to be converted to 2D data, which are then displayed on the display screen.

Abstract: A multimedia computer system for scheduling and coordinating distributed multimedia resources is disclosed. The scheduling and coordinating are accomplished by the operation of an algorithm in the memory of a number of networked computers. The processor, under the control of the algorithm, creates, accesses, modifies and stores a plurality of data structures in a file on a non-volatile store such as a disk. The data structures store user inputs defining the parameters associated with multimedia sessions and the scheduling information necessary to support the requirements of the sessions with a specific Quality Of Service (QOS). This information is stored on each of the computers participating in the electronic meeting for subsequent use in scheduling and implementing the sessions via an Open System Interconnect (OSI) network for example.

Abstract: Disclosed are methods and apparatus that facilitate the introduction of filters, converters and effects into an active multimedia stream without interruption of the presentation. A control module or sequence permits such introduction only after verifying the presence of a sufficient supply of buffered presentation data. Responding to a user's request for introduction of a filter, the invention first determines whether its immediate implementation would cause interruption, and either introduces the filter, converter or effect into the data stream as backlogged data continues to be presented, or postpones its introduction until sufficient buffered data does exist.

Abstract: A system and method for controlling access to shared resources in a distributed computer system. Access to shared resources is controlled by a local authorization token manager. Only computer processes holding authorization tokens for the requested operation may perform that operation. Each requested operation checks for the proper token. If the token is not held by the process, it is requested. The local token manager resolves token conflicts before granting tokens. A token manager of a distributed file system export protocol also is able to request authorization tokens from the local token manager. The export protocol token manager controls authorization tokens for that particular distributed file system protocol. Multiple different export protocols may request tokens from the local token manager. The shared resources may therefore be shared by multiple different export protocols without conflict.

Abstract: To allow concurrent operation with more than one facility through the same standard programming interface, a data processing system is disclosed in which an application program can communicate with two or more system facilities via a programming interface common to the facilities, the system comprising a look-up table relating each of the facilities to corresponding entry point information for an implementation therefor of the programming interface, whereby an application program can select at any particular time which of the facilities to communicate with using the interface by extracting from the look-up table the entry point information corresponding to the implementation of the programming interface for the selected facility.

Abstract: A method and system are disclosed for processing input to a data processing system having a memory and an input device having a number of keys which represent associated characters and functions. According to the method of the present invention, a translation table is created within the memory for translating virtual key codes, which specify relative positions of associated keys, into corresponding input codes, which specify a character or function. The translation table enables virtual key codes to be translated into character codes independently of the operating system and input device utilized by the data processing system. In response to the detection of a selection of a key of the input device, a scan code representing the selected key is determined. The scan code representing the selected key is then converted into a virtual key code, which is translated into an input code utilizing the translation table. The input code is thereafter received for processing within the data processing system.

Abstract: A method and system for sequence independent configuration of adapters installed in a data processing system. Adapters such as disk drive controllers, Token Ring adapters, terminal emulators and the like each include multiple choices associated therewith which specify selected memory allocations which must be utilized in configuring the adapters. A determination is first made of the number of possible combinations of such choices which exist, and if that number is not substantial, an exhaustive evaluation of each possible combination is made to determine if a conflict exists. In the absence of a conflict, each combination is examined for an optimum allocation of memory which maximizes the number of sixteen kilobyte free memory pages remaining within the system memory after configuration for utilization by an expanded memory system.

Abstract: A computer graphics system reduces the number of lighting calculations required to render a scene having objects illuminated by light sources by classifying each primitive for objects in an illuminated scene as either hidden or visible using a z-buffer. In a first approach, only one pass is made through the display list of primitives for the scene, and lighting calculations are performed only for primitives classified as visible. In a second approach, two passes are made through the display list. In the first pass, the display list is fully traversed to set-up the z-buffer, and no lighting calculations are performed. When the second pass of the display list is performed, each primitive is classified as hidden or visible, and lighting calculations are performed for each primitive classified as visible as the display list is traversed. Lighting calculations may be performed using either Gouraud or Phong shading.

Abstract: A system of modifiable group skeletal formatting of persistent objects. The object oriented framework provides abstract classes for persistent object grouping and storage. Abstract classes define the interfaces and allow implementation details to be deferred until runtime. The implementor creates subclasses overriding the abstract methods and implementing specific group skeletal formats. Multiple formats can be defined and object instance variables set to indicate which formatter to use. The defined interfaces and methods allows interchangeable substitution of group formatters.

Abstract: A method and system are described for bi-directional data transfer between a parallel port of a first (sending) data processing system and a parallel port of a second (receiving) data processing system. The process begins by signaling the sending data processing system that the receiving data processing system is ready to receive data. The sending data processing system then transmits a first packet of data to the receiving data processing system in conjunction with an indication that the first packet of data is valid to read. After reading the first packet of data, the receiving data processing system acknowledges receipt of the first packet of data by transmitting a signal to the sending data processing system. In response to the acknowledgment signal, the sending data processing system transmits a subsequent packet of data to the receiving data processing system in conjunction with an indication that the first packet of data is no longer valid to read.