2,262 research outputs found

    Formal Generation of Executable Assertions for Application-Oriented Fault Tolerance

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    Executable assertions embedded into a distributed computing system can provide run-time assurance by ensuring that the program state, in the actual run-time environment, is consistent with the logical stage specified in the assertions; if not, then an error has occurred and a reliable communication of this diagnostic information is provided to the system such that reconfiguration and recovery can take place. Application- oriented fault tolerance is a method that provides fault detection using executable assertions based on the natural constraints of the application. This paper focuses on giving application-oriented fault tolerance a theoretical foundation by providing a mathematical model for the generation of executable assertions which detect faults in the presence of arbitrary failures. The mathematical model of choice was axiomatic program verification. A method was developed that translates a concurrent verification proof outline into an error-detecting concurrent program. This paper shows the application of the developed method to several applications

    Integrated testing and verification system for research flight software design document

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    The NASA Langley Research Center is developing the MUST (Multipurpose User-oriented Software Technology) program to cut the cost of producing research flight software through a system of software support tools. The HAL/S language is the primary subject of the design. Boeing Computer Services Company (BCS) has designed an integrated verification and testing capability as part of MUST. Documentation, verification and test options are provided with special attention on real time, multiprocessing issues. The needs of the entire software production cycle have been considered, with effective management and reduced lifecycle costs as foremost goals. Capabilities have been included in the design for static detection of data flow anomalies involving communicating concurrent processes. Some types of ill formed process synchronization and deadlock also are detected statically

    Programming MPSoC platforms: Road works ahead

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    This paper summarizes a special session on multicore/multi-processor system-on-chip (MPSoC) programming challenges. The current trend towards MPSoC platforms in most computing domains does not only mean a radical change in computer architecture. Even more important from a SW developer´s viewpoint, at the same time the classical sequential von Neumann programming model needs to be overcome. Efficient utilization of the MPSoC HW resources demands for radically new models and corresponding SW development tools, capable of exploiting the available parallelism and guaranteeing bug-free parallel SW. While several standards are established in the high-performance computing domain (e.g. OpenMP), it is clear that more innovations are required for successful\ud deployment of heterogeneous embedded MPSoC. On the other hand, at least for coming years, the freedom for disruptive programming technologies is limited by the huge amount of certified sequential code that demands for a more pragmatic, gradual tool and code replacement strategy

    Using Temporal Subsumption for Developing Efficient Error-Detecting Distributed Algorithms

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    Distributed algorithms can use executable assertions derived from program verification to detect errors at run-time. However, a complete verification proof outline contains a large number of assertions, and embedding all of them into the program to be checked at run-time would make error-detection very inefficient. The technique of temporal subsumption examines the dependencies between the individual assertions along program execution paths. In contrast to classical subsumption, where all logical expressions to be examined are true simultaneously, an assertion need only be true when the corresponding statement in the distributed program has been executed. Thus, temporal subsumption based on the set of assertions derived from a verification proof and in combination with the set of all legal states in the system, allows for the removal of (partial) assertions along execution sequences. We assume a fault model of Byzantine (malicious) behavior, and therefore an individual process cannot check itself for faults. We assume that a non-faulty process will always perform the correct computation so that once external data (obtained through communication) has been verified, the local computation does not need to be checked. A non-faulty process can thus detect faults produced by a faulty process based on the information it receives from it

    SAGA: A project to automate the management of software production systems

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    The Software Automation, Generation and Administration (SAGA) project is investigating the design and construction of practical software engineering environments for developing and maintaining aerospace systems and applications software. The research includes the practical organization of the software lifecycle, configuration management, software requirements specifications, executable specifications, design methodologies, programming, verification, validation and testing, version control, maintenance, the reuse of software, software libraries, documentation, and automated management
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