Since its first edition , the goal of the Very Large Digital Libraries workshop has been to provide researchers, practitioners and application developers with a forum fostering a constructive exchange among all key actors in the field of Very Large Digital Libraries (VLDLs). Its long-term and ambitious mission is to discuss and delineate the foundations of VLDLs as a research field in its own right, with well-defined areas, problems, solutions and open questions.
These days, realization of Digital Libraries is more demanding than in the past. On the one hand, information consumers need to have access to and elaborate over an ever growing and heterogeneous information space, virtually embracing information objects from different domains. On the other hand, information providers are interested in meeting such requirements by providing rich functionalities over such information space.
Because of the fundamental role of Digital Libraries as information production and dissemination vehicles, Digital Library research is expected to provide to information society services that have to deal with large-scale issues in terms of distribution, integration and provision of services, information objects, users and policies of use. Such systems, namely Very Large Digital Libraries, have to confront a variety of new challenges in a context having scalability, interoperability and sustainability as focal points.The need for concrete solutions is indicated by the substantial amount of resources invested by the European Commission towards the creation of large data infrastructures: DILIGENT , BRICKS  and DRIVER  in the past, and today with D4Science , DRIVER-II, CLARIN , SAPIR , D4Science-II, European Film Gateway  and Europeana .
The workshop program was structured in four sessions, featuring two invited talks and nine peer-reviewed and accepted contributions.
Data Management in VLDLs
Functionality for VLDLs
The final brainstorming session led to the common conclusion that "very large" issues in Digital Libraries should not be limited to those of "size of content", as for very large databases. Indeed, as motivated by the DELOS Reference Model for Digital Libraries , Digital Libraries are also affected by the dimensions of functionalities, policies, and users, which are equally important in this respect. For example, a Digital Library may be "very large" in terms of the communities and users it has to serve at the same time, or in terms of the heterogeneity of content that such communities bring in. Furthermore, "largeness" seems to be highly dependent on sustainability issues, often ruling the Digital Library world where funds are generally scarce and hard to guarantee for the long term. As a consequence, the adjective "very large" may label systems where the problem to be tackled might not look "that large" in other domains. For example, the adoption of GRID infrastructures or high performance computing solutions used by the physics community might not be a reasonable solution in the DL universe, unless proper business models are to be found. As a consequence, novel goals, such as sustainable and low cost hardware and software infrastructures (e.g., D-Net software toolkit , gCube Software Toolkit ) and relative business models, become crucial research avenues in this area.
The participants manifested their interest in the workshop theme and in its purpose to define the boundaries of Very Large Digital Libraries as a research field per-se. This enthusiasm manifested in the interest expressed by the attendees in future VLDL editions, with some of them willing to get involved in the relative organization and others suggesting having a special track at the next European Conference on Digital Libraries (the future "Theory and Practice on Digital Libraries", TPDL) specifically dedicated to this peculiar topic.
The VLDL2009 workshop proceedings were published as a DELOS Association publication .
The success of the workshop would have not be possible without the valuable help of the program committee members: Stavros Christodoulakis (Technical University of Crete - MUSIC/TUC, Greece), Stefan Gradman (Institut fr Bibliotheks und Informationswissenschaft, Humboldt-Universitt zu Berlin, Germany), Kat Hagedorn (OAIster Project, University of Michigan Digital Library Production Service, USA), Dean B. Krafft (National Science Digital Library Project, Cornell Information Science, USA), Yosi Mass (IBM Research Division, Haifa Research Laboratory, University Campus, Haifa, Israel), Peter Wittenburg (Max-Planck-Institute for Psycholinguistics, The Netherlands).
 Manghi P, Pagano P., Zezula P. "First Workshop on Very Large Digital Libraries VLDL 2008. Workshop Report", published at SIGMOD Record, December 2008 issue.
 "Enabling Services in Knowledge Infrastructures: The DRIVER Experience" Leonardo Candela, Donatella Castelli, , Paolo Manghi, and Pasquale Pagano, Post-proceedings of the Third Italian Research Conference on Digital Library Systems (IRCDL), Padua, Italy, 2007,
 Aloia, N., Concordia, C., Meghini, C., Implementing BRICKS, a Digital Library Management System. In: Proceedings of the Fifteenth Italian Symposium on Advanced Database Systems, SEBD 2007, 17-20 June 2007, Torre Canne, Fasano, BR, Italy, 4-15.
 Leonardo Candela, Fuat Akal, Henri Avancini, Donatella Castelli, Luigi Fusco, Veronica Guidetti, Christoph Langguth, Andrea Manzi, Pasquale Pagano, Heiko Schuldt, Manuele Simi, Michael Springmann, Laura Voicu. "DILIGENT: integrating Digital Library and Grid Technologies for a new Earth Observation Research Infrastructure." In: International Journal on Digital Libraries, Vol 7, pp 59-80, October 2007, <doi:10.1007/s00799-007-0023-8>.
 Candela, L., Castelli, D., Ferro, N., Ioannidis, Y., Koutrika, G., Meghini, C., Pagano, P., Ross, S., Soergel, D., Agosti, M., Dobreva, M., Katifori, V., Schuldt, H. The DELOS Digital Library Reference Model - Foundations for Digital Libraries, Version 0.98, February 2008.
 D-Net Software Toolkit Project, <http://www.driver-repository.eu/D-NET_release_v-1-0>.
 Proceedings of the Second Workshop on Very Large Digital Libraries, DELOS Association, October 2009, ISBN 978-888850685-2.
Copyright © 2009 Yannis Ioannidis, Paolo Manghi, and Pasquale Pagano