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From the technological perspective a portal is a dynamic Web page that consists of pluggable modules, called portlets. These portlets run in a portlet container. The container performs basic functionalities such as management of system resources and authenticating users, while portlets generate the actual Web interface. Portal developers realized that reusability of portlets is a key to the customizability of portals, and the interoperability of portlets across different container platforms in an important step towards this. Around 2001 the Java Specification Request (JSR) 168 emerged as a standard that allows portal developers, administrators and consumers to integrate standards-based portals and portlets across a variety of portal containers. Most of current science gateways are built from JSR-168 compliant portlets and provide easily customizable and reusable solutions for various purposes.

Grid portal examples

The usefulness of Grid portal technologies for computational science has been established by the number of portals being developed in Europe, the United States and Asia. In Europe the most relevant portal developer consortiums have gathered around the Enabling Grids for E-sciencE project (EGEE) and its national Grid counterparts. Some of these portals provide tools that are independent from scientific disciplines, others emphasize solutions that specific communities are familiar with and can utilize efficiently.

P-GRADE Portal provides facilities to create and execute computational simulations on cluster based Grids. Various user communities of the EGEE Grid and several European national Grids apply P-GRADE Portal as a graphical front-end to manage workflow applications on their infrastructures. While P-GRADE Portal is primarily a generic environment, it can be customized to any scientific domain by generating application specific portals from it that grants access only to pre-defined, domain specific workflows and simulations.

The NGS Applications Repository is an open access portal used to describe and list applications and their associated artefacts that are available on the National Grid Service (NGS) of the UK. Applications hosted by the repository are described using middleware agnostic documents, which can be searched for by categories of interest. The repository currently holds over 50 applications from various fields such as bioinformatics, engineering, chemistry, astrophysics or image analysis.

Outlook

The concept of content aggregation seems to still gain momentum and portal solution will likely continue to evolve significantly over the next few years. The Gartner Group recently predicted to expand on the Business Mashups concept of delivering a variety of information, tools, applications and access points through a single mechanism. Mashups are Web applications that combine data or functionality from two or more sources into a single integrated application. The term mashup implies easy, fast integration, frequently done by access to open programming interfaces and data sources to produce results that were not the original reason for producing the raw source data. An example of a mashup is the use of cartographic data from Google Maps to add location information to real estate data, thereby creating a new and distinct Web service that was not originally provided by either source.

Programmers of Grid and high performance computing portals still often find it hard to bridge between user friendly Web interfaces and low-level services of Grid middleware. Errors and faults sent back from the Grid are often difficult to interpret and deal with automatically, meanwhile it is inevitable that easy to use and autonomous portals are important tools to attract larger user communities to Grids. Grid portals will definitely improve in the near future in this respect.

References

  • M. Thomas, J Burruss, L Cinquini, G Fox, D. Gannon, I. Glilbert, G. von Laszewski, K. Jackson, D. Middleton, R. Moore, M. Pierce, B. Plale, A. Rajasekar, R. Regno, E. Roberts, D. Schissel, A. Seth, and W. Schroeder. Grid Portal Architectures for Scientific Applications. Journal of Physics, 16, pp 596-600. 2005.
  • “Web portal” entry in Wikipedia: (External Link) , last accessed 06/06/2009
  • Enabling Grids for E-sciencE project (EGEE): (External Link)
  • P. Kacsuk and G. Sipos: Multi-Grid, Multi-User Workflows in the P-GRADE Portal Journal of Grid Computing, Vol. 3, No. 3-4, Springer Publishers, pp. 221-238, 2005.
  • NGS Job Submission Portal: (External Link) , last accessed: 06/06/2009
  • “Mashup” entry in Wikipedia: (External Link) , last accessed 06/06/2009

Questions & Answers

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Source:  OpenStax, Research in a connected world. OpenStax CNX. Nov 22, 2009 Download for free at http://cnx.org/content/col10677/1.12
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