Grid技术的研究与应用进展

Development on Study and Application of Grid Technique

在网格的基础构架和应用方面,首先介绍的是网格的五层沙漏模型,该模型由构造层、连接层、资源层、汇聚层和应用层五层组成。网格问题可以定义为在虚拟组织之间实现灵活、安全的协作资源共享。虚拟组织是由个人、机构以及各种资源(包括计算机、网络和仪器设备等)组成的一个动态集合。该环境下的身份认证、授权、资源访问、资源发现以及其它许多问题,只有通过网格技术才能得到有效的解决。其次,讨论了开放网格服务结构(OpenGridServiceArchitecture)。该结构基于Grid和Webservices的概念构建,定义了一个统一的开放服务语义—网格服务(Gridservice),以及创建、命名和发现临时网格服务实例的标准机制;提供了对服务实例的透明定位和多协议绑定;支持对不同的本地运行平台的集成。最后,通过一些典型的实例讨论了网格技术的应用,包括分布式超级计算、分布式仪器系统和数据密集型计算网格。

Grid' computing has emerged as an important new field, distinguished from conventional distributed computing by its focus on largescale resource sharing, innovative applications, and, in some cases, highperformance orientation. In this article, we discuss the structure and the application of Grid. Firstly, the Five Layered Grid Architecture is reviewed, which composed by five layers named as fabric, connectivity, resource, collective and application.'Grid problem' can be defined as flexible, secure, coordinated resource sharing among dynamic collections of individuals, institutions, and resources—what called as virtual organizations. In such settings, we encounter unique authentication, authorization, resource access, resource discovery, and other challenges. It is this class of problem that is addressed by Grid technologies. Secondly, another Grid structure, OGSA(Open Grid Services Architecture) is discussed. Built on concepts and technologies from the Grid and Web services communities, this architecture defines an uniformly exposed service semantics (the Grid service); defines standard mechanisms for creating, naming, and discovering transient Grid service instances; provides location transparency and multiple protocol bindings for service instances; and supports integration with underlying native platform facilities. Finally, we discuss the applications of Grid technology. These applications involve distributed supercomputing, distributed instrumentation system, and intensive data computing. Some famous examples are also given out for demonstration.