| Scientists have predicted that the Grid will be the next wave of internet.Following the computer hardware interconnection, Web interconnection, the Grid will achieve "network is the computer" scenario, That is the whole integration of the Internet into a huge super-computer and realize sharing of computing resources, storage resources, data resources, information resources, knowledge resource. After more than 10 years of time, the Grid has entered the stage of rapid development. A large number of Application teams and research projects have launched a variety of studies on the development and use of Grid infrastructure. However, there exist many obstacles for Grid users to use the Grid. Such obstacles include the immature of Grid Environment, the dynamic and heterogeneous of Grid itself, etc. The emergence of Portal provides a solution to this problem.Portal technology is the universal implementation of a large-scale enterprise information management technology, that is in the Internet environment, integrate the various application systems, data resources and common internet Resources into Internet, according to the characteristics of each user and the different roles, form personal interface of the application, and link users together organically through the handling of incident and information.The growth of Grid Portal experienced two generations, the first generation major concern to provide basic task-oriented services, such as user authentication, job submission, data control and transmission. However, they are usually associated with Grid middleware tools closely, and this caused some inadequacies. For example, it can not custom Portal according to the demands of users, and it has some limitations. Second Generation Grid Portal has gradually emerged, it use Portlet technology to provide more specialized solutions. As the Portlets of Grid services and Portal systems are loosely coupled,it is good to make up for shortcomings of the first generation of Grid Portal.This paper is based on the "Platform EGO" and discussed how to implement EGO Grid System Portal. "Platform EGO" is thecooperation project of Grid Computing and Network Security Laboratory of Jilin University and Platform corp.. Platform EGO is a Grid platform offering virtual and automation functions, sharing all types of applications and IT resources. EGO is only responsible for Grid resource management, and only provide the basic operation of resources (such as resource allocation, adding resources and delete resources, etc) for users of Grid EGO.It will not interfere with the user how to use the allocated resources, so it requires users to use of these resources reasonable and effective.Based on the analysis and study of the characteristics of EGO and the development trend of Grid Portal, we defined the Portal to be a platform connecting users and Grid resource management software, and it should provide these basic functions: job management, EGO management and Portal management. End users can access the service of Grid without the need to know the details of a concrete realization of Grid.This paper designed a model that based on Portlet technology and access Grid resources through Web service, divided the Portal system into four layers: Client layer, Portlet layer, EGO application layer and EGO Grid layer. At the client layer, users use web browser to visit Portal. Portlet is the core of Portal, which is responsible for offering the application layer to users, for the provision of end-user interactive interface and by calling the application layer components to achieve the access of application service for different users. EGO application layer is responsible for the realization of Portal EGO specific application function, the job management module and EGO management module was implemented at this layer. EGO Grid layer is resources layer of EGO Web Portal system architecture, it is responsible for bringing together the resources and provides the most basic function of resources management, allocation and executive.The architecture of using Portlet technology and parting the EGO application layer from the Portal system has several merits:1.Portlet support individuality customization for users, which has greatly increased the accessibility Portal system. Portlet can be displayed as a small window in the form on the browser, PDA or other terminal equipment, so, each application service can be shown as anindependent window; Portlet window can be dynamically added or deleted. This is in line with the user's actual use of Grid services and the dynamic nature.2. Portal system itself used extensible open framework. With the increasing and complexity of Portal users and groups, the diversity of the Portal applications, the Portal services function will be greatly expanded.3. EGO Grid layer is special responsible for the management of resources, distributed resources in EGO can be used of by application services transparently. This makes the application layer more independent, and makes the developers to concentrate their energies on specific application logic handling and Job scheduling.4. The hierarchical of the entire system facilitates horizontal expansion. Portal system aggregates various functions of Portal to different levels, so the structure is very clear, and each targeted at different developers. The hierarchy will also enable the whole system to be upgraded, maintained and extended easily.The implementation of EGO Web Portal System used the Portal technology which has been extensive used from 2002 and developed secondarily on the basis of open source project-- Liferay Portal, as a result, the basic functions of the whole system are in a high starting point. Liferay Portal provides as single entry point, personalized interface, the full text search, user privilege management, and other aspects of the powerful functions. These powerful functions will shorten the development cycle and reduce the difficulty. At other aspects, reference of J2EE, Web Services and Component Technology has improved the system's flexibility and efficiency, reduce the maintenance workload, and strengthen the technological advantages of the system. In the model of job management, the author defined the interface separately for each level and implemented the matrix multiplication and the sort use cases simply. According to their needs, users can use and learn from these two use cases on the application functional expansion of Portal.Generally speaking, the design idea and technology this paper presents mesh with the current direction of development and trends of Grid, the practical use of the system also reflects the basic structuraladvantages, and there is a definite reference value in the Portal design within Grid environment. |
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