Publications

Abstract not provided.

The Simulation Intranet/Product Database Operator (SI/PDO) project has developed a Web-based distributed object architecture for high performance scientific simulation. A Web-based Java interface guides designers through the design and analysis cycle via solid and analytical modeling, meshing, finite element simulation, and various forms of visualization. The SI/PDO architecture has evolved in steps towards satisfying Sandia's long-term goal of providing an end-to-end set of services for high fidelity full physics simulations in a high-performance, distributed, and distance computing environment. This paper describes the continuing evolution of the architecture to provide high-performance visualization services. Extensions to the SI/PDO architecture allow web access to visualization tools that run on MP systems. This architecture makes these tools more easily accessible by providing web-based interfaces and by shielding the user from the details of these computing environments. The design is a multi-tier architecture, where the Java-based GUI tier runs on a web browser and provides image display and control functions. The computation tier runs on MP machines. The middle tiers provide custom communication with MP machines, remote file selection, remote launching of services, load balancing, and machine selection. The architecture allows middleware of various types (CORBA, COM, RMI, sockets, etc.) to connect the tiers depending upon the situation. Testing of constantly developing visualization tools can be done in an environment where there are only two tiers which both run on desktop machines. This allows fast testing turnaround and does not use compute cycles on high-performance machines. Once the code and interfaces are tested, they are moved to high-performance machines, and new tiers are added to handle the problems of using these machines. Uniform interfaces are used throughout the tiers to allow this flexibility. Experiments test the appropriate level of interface: either a large set of specific function calls or a small set of generic function calls. This architecture is based on the goals and constraints of the environment: huge data volumes (that cannot be easily moved), use of multiple middleware protocols, MP platform portability, rapid development of the visualization tools, distributed resource management (of MP resources), and the use of existing visualization tools.

Design Tools use a Web-based Java interface to guide a product designer through the design-to-analysis cycle for a specific, well-constrained design problem. When these Design Tools are mapped onto a Web-based distributed architecture for high-performance computing, the result is a family of Distributed Design Tools (DDTs). The software components that enable this mapping consist of a Task Sequencer, a generic Script Execution Service, and the storage of both data and metadata in an active, object-oriented database called the Product Database Operator (PDO). The benefits of DDTs include improved security, reliability, scalability (in both problem size and computing hardware), robustness, and reusability. In addition, access to the PDO unlocks its wide range of services for distributed components, such as lookup and launch capability, persistent shared memory for communication between cooperating services, state management, event notification, and archival of design-to-analysis session data.

The Simdarion Infranet (S1) is a term which is being used to dcscribc one element of a multidisciplinary distributed and distance computing initiative known as DisCom2 at Sandia National Laboratory (http ct al. 1998). The Simulation Intranet is an architecture for satisfying Sandia's long term goal of providing an end- to-end set of scrviccs for high fidelity full physics simu- lations in a high performance, distributed, and distance computing environment. The Intranet Architecture group was formed to apply current distributed object technologies to this problcm. For the hardware architec- tures and software models involved with the current simulation process, a CORBA-based architecture is best suited to meet Sandia's needs. This paper presents the initial desi-a and implementation of this Intranct based on a three-tier Network Computing Architecture(NCA). The major parts of the architecture include: the Web Cli- ent, the Business Objects, and Data Persistence.