Grid computing refers to an infrastructure that enables the integrated, collaborative use of high-end computers, networks, databases, and scientific instruments owned and managed by multiple organizations. Grid applications often involve large amounts of data and computing and often require secure resource sharing across organizational boundaries, and are thus not easily handled by current Internet and Web infrastructures.
The term "grid computing" was coined in the early 1990s based on advanced concepts for distributed computing architectures and infrastructure, and by analogy with the electric power grid. The fundamental capabilities embodied by grid computing are the cross-institutional sharing of computing resources and dynamic problem solving.
A key concept in grid computing is the service. Computational resources (computers, storage systems, network infrastructure, software libraries and tools, etc.) will present themselves within the grid as a service. This could entail resource brokering and scheduling services, or even computational services, such as database services. Applications may also present themselves as higher-level services that rely on other lower-level services (computing and storage). For example, a service could allow a user to search a catalog of remote-sensing data for data sets that satisfy a specific temporal and geographic query, then extract a subset of this data and move it to another system for additional data processing, such as feature identification.
Capabilities that are most relevant to the Advanced Data Grid project include:
Resource Discovery. In an open-ended environment, the user must be able to find the required resources. This can be done through a combination of search engines and catalogs that form an information service; however, standard metadata schemas must be developed to enable the discovery process.
Resource Brokering and Scheduling. Once desirable resources are found, their actual use may have to be brokered and scheduled.
Security. Simple passwords do not provide sufficient security; the grid computing community has adopted the use of X.509 certificates to enable strong authentication and authorization.
Monitoring. Grids will have both health and performance monitoring systems that are integral to their operation.