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SAMGrid
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Grid Technology
To satisfy emerging IT needs in the scientific, industrial, governmental and commercial arenas, grid computing has been conceived as an expansion of distributed computing. Grid computing involves the distribution of computing resources among geographically separated sites (creating a "grid" of resources), all of which are configured with specialized software for routing jobs, authenticating users, monitoring resources, and so on. Shared, site-based computing resources may include computing and/or storage nodes (see Condor), software (e.g., Open Channel Software), data (e.g., GriPhyN), a variety of scientific instruments, and so on.
Grid computing aims to provide reliable and secure access to widely scattered resources for authorized users located virtually anywhere in the world. When a user submits a job, the grid software controls where the job gets sent for processing. Think of a grid as a utility, much like the electrical utility grid. A company may buy electric power from a variety of physically separate sources, pool it, and distribute it to all its customers with high reliabililty. The customers don't need to know where their electricity originates, just that their wall sockets always work. In grid computing, the end user doesn't need know where particular resources reside, just that they are available with high reliability.
Grid development is happening in many sectors, not just in scientific research. The Global Grid Forum (GGF) is a community-initiated forum of 5000+ individual researchers and practitioners working on grid technologies. GGF's primary objective is to promote and support the development, deployment, and implementation of Grid technologies and applications via the creation and documentation of "best practices" - technical specifications, user experiences, and implementation guidelines.
Grid software tools which have become de facto standards include the Globus Toolkit and the Virtual Data Toolkit (VDT). The Open Science Grid (OSG), a US grid computing infrastructure that supports scientific computing, and in which Fermilab participates, implements these tools and is contributing to further development of them.
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Virtual Organizations
Grids are being designed for use in HEP collaborations, e.g., CMS, CDF, D0 (SAM) and other organizations of the same general model. These organizations consist of individuals from many different home institutions. Individuals as well as institutions may come and go over time. In grid terminology, these are called dynamic virtual organizations (or VOs). A grid can be setup to be usable by multiple VOs.
Open Science Grid (OSG) computing and storage resources are typically allocated for use by specific Virtual Organizations (VOs). In order to use these OSG resources, you must register your Grid credentials with one (or more) participating VOs. Many OSG resources allow some amount of opportunistic use, but the user must still be registered with a VO.
Certificates and Grid Security
Maintaining security within a grid is very important. Authentication of users (knowing their identity) is an important aspect of security. The VO must control which individuals join the organization and make its list of members available to the software that controls and monitors the grid. Grid user authentication is based on certificates, which are unique identifiers for individuals. Find information about certificates, and instructions for obtaining and using them, at this link.
Further Information on Grid Technology
Grid projects in which Fermilab participates
Request a certificate from: DOEGrids Certificate Service (Fermilab users, go to Certificates at Fermilab).
The Anatomy of the Grid (Enabling Scalable Virtual Organizations), Foster, Kesselman, Tuecke
http://www.globus.org/alliance/publications/papers/anatomy.pdf
Grid Computing Oracle Style (Oracle, Linux, and The Grid), Rob Reilly
http://www.linuxplanet.com/linuxplanet/reports/4661/1/
The Physiology of the Grid (An Open Grid Services Architecture for Distributed Systems Integration) , Foster, Kesselman, Nick, Tuecke
http://www.globus.org/alliance/publications/papers/ogsa.pdf
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