Sites of the DILIGENT Pre Production Service, including gLite sites (green) and DILIGENT Hosting Node Managers (yellow). Image courtesy DILIGENT

WhatÂ’s digital, can manage any information you might have, but doesnÂ’t exist until you ask for it? Digital libraries, according to Pasquale Pagano from the Digital Library Infrastructure on Grid Enabled Technologies project.

“DILIGENT wants to go beyond static digital libraries to provide an infrastructure to create and manage dynamic, virtual digital libraries using grid technology,” explains Pagano, the project’s technical director.

A prototype system for creating such dynamic digital libraries has been achieved by deploying the DILIGENT tools and services on top of a basic grid infrastructure layer. The infrastructure comprises sites from DILIGENT and from the Enabling Grids for E-sciencE projectÂ’s Pre-Production Service.

"DILIGENT doesn't operate a full infrastructure itself,” says Pagano, “so approaching EGEE was a natural choice. Already, eight sites on EGEE's PPS have offered to support the DILIGENT virtual organization, giving us an excellent chance to test our services and disseminate our work.” DILIGENT also provides two sites to the PPS, and the cooperation benefits both projects and promotes cross-fertilization between the grid and the digital library domains.

On top of the grid infrastructure run the digital library-specific services, executed from a series of Hosting Node Managers. These services provide all the high-level functions needed to dynamically use and manage digital libraries.

"By using this technology we can provide autonomic behavior of the infrastructure," adds Pagano. "Not only are services deployed based on the needs of each digital library, but if one service is overloaded or a failure occurs, the system will deploy a new instance of the service on a different machine. We can also provide usage optimization and terminate services when they are not being used. By providing these functionalities we deliver a framework where users can plug-and-play new components, allowing them to design the workflows needed for their own communities in a simple, dynamic way.”

Learn more at the DILIGENT Web site.

-Owen Appleton, EGEE