Next Generation Software: Supporting Complex Application Requirements in Metasystems

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EIA-9974968Grimshaw, Andrew S.University of VirginiaNext Generation Software: Supporting Complex Application Requirements in Metasystems The proposed work addresses two critical problems facing metasystems applications designers: a lack of a sufficient set of tools by which to structure their applications, predict performance, and make scheduling decisions; and a lack of application-level fault-tolerance techniques. This proposal will address these problems by building upon our past experiences with Legion, which is an architecture for designing and building system services that provides to users the illusion of a single virtual machine with secure shared objects and shared name spaces. The single virtual machine may consist of hundreds of distributed and heterogeneous resources in multiple administration domains.IDAEMA (Integrated Design, Analysis, and Execution of Metasystems Applications) is a multi-stage advice and performance prediction tool for metasystems. During application design, IDAEMA uses a library of cataloged research results based on application characteristics and high-level application requirements to provide analysis and advice regarding how to structure the program. This advice provides multiple views that describe the implications of design choices on application requirements, software engineering costs, and predicted performance-from advice in how to get started programming in a metasystems environment to code templates and existing components upon which to base the functionality of the application. At run-time, IDAEMA uses static and dynamic information about the hardware and software of the target metasystem in combination with the application user's security, fault-tolerance, predictability and cost requirements to provide assistance and performance prediction at multiple levels of abstraction and resolution. Our approach to fault-tolerance is based upon our use of the RFE model (Reflective Graph and Event) and the conviction that no single fault-tolerance mechanism is appropriate for all applications. Instead application must be free to use a variety of different techniques, all in the same system. RGE provides a flexible, configurable mechanism for attaching arbitrary computation in the form of program graphs to events. Exoevents, Exoevent Interests, and Exoevent Interest Sets are used to dynamically configure application-specific fault-tolerance techniques. Together, these two components provide new flexibility and predictability for metasystems application development and execution. IDAEMA and the RGE model are validated through proposed modifications to Legion in combination with collaborators at NPACI site developing applications that include a coupled ocean-climate model and a full-scale simulation of an integrated system for intelligent processing of materials.