容错计算机的主要设计目标是为了提高计算机系统的可靠性和(1)。提高计算机可靠性的技术可以分为(2)和(3)。后者主要运用行冗余技术来抵消由于故障而引起的影响。而冗余一般可以分为(4)。

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Originally, the World-Wide Web was designed as information medium for(71) research teams. A deliberately simple implementation model was chosen to make it as simple as possible for authors to(72) documents to the web, and to(73)these in the sense of updating content. This implementation model is centered around the notion of resources, usually file-based. For the (74)intended use of the web, resources presented a useful abstraction, as they related to relatively self-contained chunks of information such as research publications and (75) pages. Such chunks of information typically could be set up and maintained independently of other resources, so that resources were the appropriate abstraction for composition and modification.

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UML-based tools are often used for J2EE/.NET application analysis and design，both because UML's object orientation is ideal for the J2EE/.NET implementation(66) and because of the expanding scope and complexity of today's enterprise endeavors．(67) the approaches diverge at the coding/implementation phase，a common Set of analysis and design techniques applies to both J2EEand.NET．

 The use of a virtual machine (VM) architecture is also common to J2EE and .NET. Application development tools(68) intermediate-level code instead of platform-specific binary code, which means the VM interprets that code in real time or performs Just-In-Time (JIT) compilation; the Microsoft VM always runs JIT-compiled code. This VM-based model results in(69)-independent applications and is conducive to the late-binding technique that's(70) to the OO approach.