On the Semantics of Coordination Models for Distributed Systems: The LogOp Case Study
On the Semantics of Coordination Models for Distributed Systems: The LogOp Case Study
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DOI：
10.1016/j.entcs.2004.04.033
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发表时间：
2004-07
期刊：
影响因子：
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通讯作者：
R. Menezes;Andrea Omicini;Mirko Viroli
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文献类型：
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作者：
R. Menezes;Andrea Omicini;Mirko Viroli
LogOp是一个扩展了琳达的协调模型，它允许单个协调操作动态地处理多个可能分布的元组空间。LogOp的设计提出了协调和分布式系统工程领域普遍感兴趣的相关问题。特别是，设计的基础设施，支持制定协调法律，涉及多个物理分布的元组空间需要仔细处理的同步性，原子性，局部性的相互作用，和全球的协调规则的解释有关的方面。在本文中，我们阐述了这些一般性的问题，从研究的语义LogOp。首先，引入LogOp协调模型作为琳达模型的扩展。然后，两种不同的语义，都符合LogOp的非正式规范，正式描述和比较。最后，传统的方法的协调（协调作为一种语言）的正式表征的局限性，并通过不同的方法（协调作为一种服务），其好处是通过适当的重新制定LogOp语义说明。一方面，这提供了关于如何将LogOp协调模型部署为分布式系统的协调基础设施提供的交互式服务的关键提示。另一方面，上述结果允许在开放和分布式系统中的协调的一些一般方面被清楚地指出，并充分讨论。
LogOp is a coordination model extending Linda by allowing a single coordination operation to dynamically address a multiplicity of possibly distributed tuple spaces. The design of LogOp raises relevant issues that are of general interest in the fields of coordination and distributed systems engineering. In particular, the design of an infrastructure that supports the enactment of coordination laws involving a multiplicity of physically distributed tuple spaces demands a careful treatment of the aspects related to synchrony, atomicity, locality of interactions, and global interpretation of coordination rules. In this paper we elaborate on these general issues, starting from the study of the semantics of LogOp. First of all, the LogOp coordination model is introduced as an extension of Linda. Then, two different semantics, both conforming to the LogOp informal specification, are formally described and compared. Finally, the limitations of the traditional approach to the formal characterisation of coordination (coordination as a language) are pointed out, and addressed through a different approach (coordination as a service) whose benefits are illustrated by suitably re-formulating LogOp semantics. On the one hand, this provides crucial hints on how the LogOp coordination model could be deployed as an interactive service provided by a coordination infrastructure for distributed systems. On the other hand, the above results allow some general aspects of coordination in open and distributed systems to be clearly pointed out and adequately discussed.