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Research paper : How Grid enables E-Science? (Y. Tanaka)−39−Synthesiology - English edition Vol.2 No.1 (2009) and appropriate management of the secret key are burdens for the user, and the provision of a simple interface was felt necessary. Therefore, we created a mechanism for managing the user’s account and certificate on the server side using the GAMA (Grid Account Management Architecture)[18], developed by the San Diego Supercomputer Center. GAMA is software where functions such as a request from a user for opening an account, and login and account administrator functions for user management are provided as a portlet. The user account is managed by the GAMA server, and the GAMA server has functions such as an authorization station to issue certificates to the user. By using GAMA, the user can access the GEO Grid information infrastructure via authorization by user name and password, without obtaining or managing the secret key or certificate by him/herself.GridSphere[19] is used as a portal for users. GridSphere is a framework for constructing a portal based on JSR168[20], that has been standardized by the Java Community Process as an API for creating small web components called “portlet,” used for portal applications. It provides the authorization module needed to create the proxy certificate from the GAMA server and the portlet for the portal administrator. The original GAMA authorization module only obtains the proxy certificate from the GAMA server and does not include an interface with VOMS. Therefore, we modified the GAMA authorization module so the VOMS proxy certificate is created by a query to the VOMS server after the proxy certificate is obtained from the GAMA server.4.6 Integration of elemental technologyThe basic technologies described in this chapter are compatible with all security requirements based on GSI, and in addition to the implementation of the interface for VOMS in the account management system, integration through interfaces provided by each middleware suite is possible. In constructing a large-scale system like the GEO Grid, it is not realistic to develop everything on our own, and it is important to reduce the development cost by actively utilizing available technologies, while maintaining the core competence.5 Construction of the actual systemBased on the proposed architecture, we implemented a system in which the main target was ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer)[21], a collection of satellite data (Fig. 2). This system is composed of a gateway server that provides access to the GEO Grid cluster through GRAM and Grid FTP server, a server to provide metadata and a catalog of ASTER data, a map server to provide image data as WMS, a GIS server to provide high-grade data such as WFS and WCS, and GAMA and VOMS servers that conduct account management. In this system, three VOs for environment, disaster prevention, and information, currently exist, and each is currently in actual operation, where users are actually using them. ASTER consists of sensors loaded on a satellite called Terra, launched by NASA. There are two sensors loaded, and an elevation model of the earth’s surface can be calculated from the results of these observations. ASTER data has been stored in a tape library managed by the Earth Remote Sensing Data Analysis Center (ERSDAC) since the launch of Terra, and is provided to users as fee-based data. Since last year, the data has been supplied to AIST, and at AIST, the ASTER data is stored in a cluster file system rather than as a tape library. The cluster (a GEO Grid cluster) used is composed of 36 dual Xeon nodes connected by Giga-bit Ethernet, and its capacity is 264 TB, in total. The cluster GETGSI + VOMSWFSWCSWMSCSWDataMapsMeta dataStorage(DEM)GEO Grid ClusterERSDIS/NASATDRSTerra/ASTERAPAN/TransPACqueryexecOGSADAIGRAMGridFTPGSI + VOMSLCAS/LCMAPSGSI + VOMSAccountDBVO DBVO (VOMS)serverAccount server(GAMA)Authorizationinformationgatewayservercatalogue/metadataservermapserverGISserverPortal serverLoginUserFig. 2 Architecture of the GEO Grid system

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