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Software, IEE Proceedings -

Issue 3 • Date Jun 2000

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Displaying Results 1 - 4 of 4
  • FADI: a fault tolerant environment for open distributed computing

    Page(s): 91 - 99
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (636 KB)  

    FADI (fault tolerant distributed environment) is a complete programming environment for the reliable execution of distributed application programs. FADI encompasses all aspects of modern fault-tolerant distributed computing. The built-in user-transparent error detection mechanism covers processor node crashes and hardware transient failures. The mechanism also integrates user-assisted error checks into the system failure model. The nucleus non-blocking checkpointing mechanism combined with a novel selective message logging technique delivers an efficient, low-overhead backup and recovery mechanism for distributed processes. FADI also provides a means of remote automatic process allocation on distributed system nodes View full abstract»

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  • Faulty version recovery in object-oriented N-version programming

    Page(s): 81 - 90
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (764 KB)  

    Many long-running applications would greatly benefit from being able to recover faulty versions in N-version programs since their exclusion from further use undermines the availability of the system. Developing a recovery feature, however, is a very complex and error-prone task, which the author believes has not received adequate attention. Although many researchers are aware of the importance of version recovery, there are very few schemes which include these features. Even when they do, they rely on ad hoc programming and are not suitable for object-oriented systems. The author believes that developing systematic approaches here is crucial, and formulates a general approach to version recovery in class diversity schemes, which is based on the concept of the abstract version state. The approach extends the recently-developed class diversity scheme and relies on important ideas motivated by community error recovery. The diversity scheme includes two-level error detection which allows error latency to be controlled. To use it, special application-specific methods for each version object have to be designed, which would map the internal state into the abstract state and at the same time, form a basis for one-level version recovery. The approach is discussed in detail, compared with the existing solutions, and additional benefits of using the abstract version state are shown. The intention is to outline a disciplined way for providing version recovery and thus make it more practical. Two promising approaches which can be used for developing new structuring techniques incorporating the abstract version state concept are discussed View full abstract»

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  • Early generation of performance models for object-oriented systems

    Page(s): 61 - 72
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (664 KB)  

    Exploiting features of the OMT-based object-oriented approach, the paper presents a method for performance assessment early in the lifecycle, and before the design phase. To this end the actor-event graphs (AEG) formalism is presented that provides an intermediate model between specification models and software performance models. The AEG formalism unifies performance relevant information contained in various OMT models (class diagrams, interaction diagrams, state transition diagrams) into a single representation. Two algorithms deriving AEGs from different analysis results are described and the effectiveness of the approach is illustrated by an application case study View full abstract»

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  • The logic of software design

    Page(s): 73 - 80
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (544 KB)  

    The authors provide an overview of how logic can be used throughout the software development cycle, and discuss what methods can be introduced in the computer science curriculum to support software development. To see how logic is useful throughout the cycle, they present the WRSM reference model, and illustrate it with simple motivating examples. Reasoning is performed in Logic E, and PVS is used to illustrate automated proofs View full abstract»

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