While the articles for this reading assignment were published between 1997 and 2001, they provide valuable definitions for terms used in describing models and architecture for digital libraries. The papers also address major themes in this filed of librarianship, including interoperability, extensibility, security, the need for open architecture. That being said, it would be interesting to read about current developments in this area during the last eight years.
A Framework for Building Open Digital Libraries. Suleman, Hussein and Edward A. Fox.
This article discusses a project, which focuses on the design and implementation of interoperability standards, which form the basis for a framework of components for
building extensible digital libraries (DLs). The thrust of the argument is that open architecture is necessary for interoperability between DLs and that a component-based system using standard protocol is ideal for designing the framework, as it supports extensibility.
An Architechture for Information in Digital Libraries. Arms, William Y. et al.
This article explains how digital objects are stored and indexed for retrieval. Metadata, handles, digital objects and meta-objects are all defined.
Perhaps what is most confusing is understanding the concept of meta-object by defining key metadata, structural metadata and data about each version of the object. If meta-objects are used to aggregate digital objects, Meta-objects “provide links to all versions of the item and to all structural metadata. This eliminates the need for all the details for a set of digital objects. It is an index for a group of similar objects. Could one argue that this is meta-data about a set of objects?
Interoperability for Digital Objects and Repositories. Payette, Sandra.
This study looks at the interoperability and extensibility of digital library systems “through the definition of key digital library services and their open interfaces.” The purpose is to foster a general level of information sharing between communities.
Disseminators are used to “extend the behavior of digital objects, enabling clients to interact with then through semantically rich environments.”
Disseminator Type is “a set of operations that extends the basic functionality of a digital object.” Ex, turn page in book or translate page from French to English. Disseminator Types are also called a signatures. The authors explain that “since new community-specific notions of content will continue to appear, there must be mechanisms for defining and registering new Disseminator Types.” So, communities can develop their own Disseminator Types by formally defining sets of operations that reflect the desired functionality of a particular content abstraction.” (p. 6 of14)
A Servlet “is an executable program that is capable of performing the set of operations defined for a specific Disseminator Type. It is identified by the URN of a stored signature.
“Signatures and servlets become available throughout the infrastructure when they are stored in Digital Objects and their URNs are registered with the naming service (handle system). The importance of a global naming service is highlighted in this test. The repositories consult with the Handle System to locate these special digital objects to obtain disseminator Signatures and Servlets as needed. This occurs when clients make requests..” (p. 9 of 14)
What is the internet (And What Makes It Work) Robert E, Kahn.
This paper discusses the technological developments including packet switching and routers, which allowed for the development of an Internet at the Department of Defense and at universities, and which later was opened up to the public at large through the use of TCP/IP protocols.
An interesting point raised by the authors is that as a result of this technology the world should now be viewed as information centric rather than as communication centric. (P 11 of 13)
