Fundamental design problems of distributed systems for the hard-real-time environment
Fundamental design problems of distributed systems for the hard-real-time environment
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发表时间：
1983-06
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通讯作者：
A. Mok
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作者：
A. Mok
设计用于在必须满足严格时序约束的硬实时环境中运行的软件，通常需要对编程语言和支持它的底层系统进行隐含假设。逻辑正确的程序，即，它们实现预期的算法，如果它们假定的软件定时特性或者如果可表达的定时特性不能在运行时间之前被验证，则它们可能不能正确地工作。特别是对于分布式系统，软件必须针对无数的实现参数进行定制，例如，通信带宽，从而使后续修改变得危险。我们的研究探讨了硬实时软件的设计和维护自动化的基本问题。在研究了传统的实时软件设计方法通过基于过程的模型的局限性之后，我们将提供一个基于图的计算模型，它更适合于表达实时环境的计算需求。该模型是CONSORT（控制结构优化的实时），实验软件设计系统，已实现生成过程控制应用程序的框图模式的扩展。虽然我们的基于图的模型是抽象的，它可以作为一个有用的文本需求规范和目标应用程序之间的中间表示。使用基于图的模型，相关的资源分配问题，以满足严格的时间约束的复杂性进行了研究。
Software designed to function in a hard-real-time environment where strict timing constraints must be met often entails implicit assumptions about a programming language and the underlying system which supports it. Programs which are logically correct, i.e., they implement the intended algorithms, may not function correctly if their assumed timing characteristics of the software or if the expressible timing characteristics cannot be verified before run time. For distributed systems in particular, the software must be tailored to a myriad of implementation parameters, e.g., communication bandwidth, thus rendering subsequent modifications hazardous. Our research investigates the basic problems in automating the design and maintenance of hard real-time software. After examining the limitations of the traditional approach to real-time software design via process-based models, we shall provide a graph-based computation model which is more suitable for expressing the computation requirements of the real-time environment. This model is an extension of CONSORT (Control Structure Optimized for Real-Time), an experimental software design system which has been implemented to generate process control application programs from block diagram schemata. While our graph-based model is abstract, it can serve as a useful intermediate representation between textual requirements specifications and target application programs. Using the graph-based model, the complexity of the relevant resource allocation problems for meeting stringent timing constraints is investigated.