4,467 research outputs found

    A methodology for producing reliable software, volume 1

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    An investigation into the areas having an impact on producing reliable software including automated verification tools, software modeling, testing techniques, structured programming, and management techniques is presented. This final report contains the results of this investigation, analysis of each technique, and the definition of a methodology for producing reliable software

    CCL: a portable and tunable collective communication library for scalable parallel computers

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    A collective communication library for parallel computers includes frequently used operations such as broadcast, reduce, scatter, gather, concatenate, synchronize, and shift. Such a library provides users with a convenient programming interface, efficient communication operations, and the advantage of portability. A library of this nature, the Collective Communication Library (CCL), intended for the line of scalable parallel computer products by IBM, has been designed. CCL is part of the parallel application programming interface of the recently announced IBM 9076 Scalable POWERparallel System 1 (SP1). In this paper, we examine several issues related to the functionality, correctness, and performance of a portable collective communication library while focusing on three novel aspects in the design and implementation of CCL: 1) the introduction of process groups, 2) the definition of semantics that ensures correctness, and 3) the design of new and tunable algorithms based on a realistic point-to-point communication model

    Advanced software techniques for space shuttle data management systems Final report

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    Airborne/spaceborn computer design and techniques for space shuttle data management system

    Guidelines for development structured FORTRAN programs

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    Computer programming and coding standards were compiled to serve as guidelines for the uniform writing of FORTRAN 77 programs at NASA Langley. Software development philosophy, documentation, general coding conventions, and specific FORTRAN coding constraints are discussed

    Evolving Fortran types with inferred units-of-measure

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    Dimensional analysis is a well known technique for checking the consistency of equations involv- ing physical quantities, constituting a kind of type system. Various type systems for dimensional analysis, and its re nement to units-of-measure, have been proposed. In this paper, we detail the design and implementation of a units-of-measure system for Fortran, provided as a pre- processor. Our system is designed to aid adding units to existing code base: units may be polymorphic and can be inferred. Furthermore, we introduce a technique for reporting to the user a set of critical variables which should be explicitly annotated with units to get the maxi- mum amount of unit information with the minimal number of explicit declarations. This aids adoption of our type system to existing code bases, of which there are many in computational science projects.This work was supported in part by a Google Focussed Research Award and by EPSRC grant EP/K011715/1.This is the final version. It first appeared at http://www.sciencedirect.com/science/article/pii/S1877750315000563

    Software reliability: Repetitive run experimentation and modeling

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    A software experiment conducted with repetitive run sampling is reported. Independently generated input data was used to verify that interfailure times are very nearly exponentially distributed and to obtain good estimates of the failure rates of individual errors and demonstrate how widely they vary. This fact invalidates many of the popular software reliability models now in use. The log failure rate of interfailure time was nearly linear as a function of the number of errors corrected. A new model of software reliability is proposed that incorporates these observations

    Glossary of Software Engineering Laboratory terms

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    A glossary of terms used in the Software Engineering Laboratory (SEL) is given. The terms are defined within the context of the software development environment for flight dynamics at the Goddard Space Flight Center. A concise reference for clarifying the language employed in SEL documents and data collection forms is given. Basic software engineering concepts are explained and standard definitions for use by SEL personnel are established
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