Lightweight Reference Models and the OCKHAM Framework Martin Halbert Director for Library Systems, Emory University ECDL 2002 Monday, September 16, 2002

Overview The practical need for coordination of DL development efforts The DLF OCKHAM meetings Lightweight Reference Models Next Steps Discussion questions September 16, 2002 OCKHAM / ECDL 2002

The Problem Digital library development is complex and expensive Various DL development communities (in the USA at least) are not working together well Results are much incompatibility, little common practice, slow progress, and no leverage in investment If this continues, we are just going to languish and fester Digital library infrastructures seek to provide integrated access to complex information content To date this has primarily been accomplished in operational settings by means of very expensive propriety systems that are monolithic, interoperate poorly, and require Byzantine implementation efforts September 16, 2002 OCKHAM / ECDL 2002

The Possibilities Most DL operations feel quite limited in resources individually But as a group we are quite large Better cooperation would lead to mutually beneficial ends through standards The vast majority of digital library operations are individually quite limited in the infrastructures and tools they can develop or purchase But as a group we are quite large there is no reason we cannot cooperate toward mutually beneficial ends through standards What has worked before? Unix flourished where many monolithic behemoths failed because of its philosophical differences September 16, 2002 OCKHAM / ECDL 2002

The DLF OCKHAM Meetings Convened to seek out practical possibilities for common architectural approaches and open standards Hope was to find ways to leverage development costs and foster better interoperation of DL’s Brought together people from several DL communities for discussions in May 2002 September 16, 2002 OCKHAM / ECDL 2002

OCKHAM Activities Compared major DL architectures for commonalities (OAIS, DNER, etc.) Analyzed the specific benefits of shared reference models and standardized lightweight protocols Brainstormed possible collaborative projects Broadly discussed related issues September 16, 2002 OCKHAM / ECDL 2002

Lightweight Protocols “Lightweight”, or relatively small and simple protocols seem to have clear advantages over “Full” protocols that attempt to be comprehensive Successes of protocols considered lightweight is illuminating Examples: TCP/IP, HTTP, LDAP, and the OAI PMH September 16, 2002 OCKHAM / ECDL 2002

Reference Models Reference Model: a common vocabulary and description of components, services, and inter-relationships that comprise a system under consideration Useful as a tool to foster consensus and common understanding in a time of rapid change and/or disagreement From Carnegie Mellon Software Engineering Institute Reference model. A reference model is a description of all of the possible software components, component services (functions), and the relationships between them (how these components are put together and how they will interact). Examples of commonly-known reference models include the following: the Technical Architecture for Information Management (TAFIM) reference model (see TAFIM Reference Model) the Reference Model for Frameworks of Software Engineering Environments [ECMA 93] Project Support Environment Reference Model (PSERM) the Tri-Service Working Group Open Systems Reference Model Architecture. An architecture is a description of a subset of the reference model's component services that have been selected to meet a specific system's requirements. In other words, not all of the reference model's component services need to be included in a specific architecture. There can be many architectures derived from the same reference model. The associated standards and guidelines for each service included in the architecture form the open systems architecture and become the criteria for implementing the system. Implementation. The implementation is a product that results from selecting (e.g., commercial-off-the-shelf), reusing, building and integrating software components and component services according to the specified architecture. The selected, reused, and/or built components and component services must comply 100% with the associated standards and guidelines for the implementation to be considered compliant. September 16, 2002 OCKHAM / ECDL 2002

Lightweight (Protocol) Reference Models Builds on successful example of the OAI PMH, clearly understood minimalist concept of metadata distribution, implemented in simple protocol Leads to developing simple reference models of specific subsystems, with associated simple protocols and standards September 16, 2002 OCKHAM / ECDL 2002

Some LRM Ideas Pathfinder brokerage Electronic reserves syllabi September 16, 2002 OCKHAM / ECDL 2002

Next Steps Agreed to at May DLF meetings Continue the OCKHAM discussions in DLF and elsewhere Pursue “catalytic” projects to test and flesh out the LRM concept Discussed afterwards on listserv Contextualize via the Keystone Principles Explore possibility of linkage with OKI September 16, 2002 OCKHAM / ECDL 2002

The Keystone Principles “A set of principles and action items to guide academic libraries' efforts and establish a foundation for joint future-oriented action based on traditional academic library values” Developed in 1999 by 80 academic library leaders in Keystone, Colorado September 16, 2002 OCKHAM / ECDL 2002

Keystone Principle Two “Libraries are responsible for creating innovative information systems for the dissemination and preservation of information and new knowledge regardless of format.” “Libraries will create interoperability in the systems they develop and create open source software for the access, dissemination, and management of information.” September 16, 2002 OCKHAM / ECDL 2002

The Open Knowledge Initiative Collaborative project funded by Andrew W. Mellon Foundation, centered at MIT & Stanford, with other participants “Defining open architectural specifications to support the development of educational software, especially courseware systems” “Its architecture will provide a modular and extensible development platform for building both traditional and innovative educational applications to help institutions leverage existing infrastructure” September 16, 2002 OCKHAM / ECDL 2002

OKI (cont.) “The OKI product is designed for broad adoption in the university setting.” “It will simplify the methods of assembly, delivery and access to educational technology resources, while creating a large collaborative community.” Cooperating with the IMS Global Learning Consortium and Advanced Distributed Learning initiative Relatively little contact with the DL development community, apparently September 16, 2002 OCKHAM / ECDL 2002

OCKHAM & OKI May be that OCKHAM can make faster progress by simply adopting OKI common services API set Possibility of using OKI standards for DL development efforts will be explored September 16, 2002 OCKHAM / ECDL 2002

Discussion Questions What suggestions do you have for ways to: leverage DL development costs? foster better interoperability? build bridges between various DL communities? identify initiatives with related aims? September 16, 2002 OCKHAM / ECDL 2002

Contacts/URLs Martin Halbert New OCKHAM URL: Phone 404-727-2204 Email: mhalber@emory.edu New OCKHAM URL: http://ockham.library.emory.edu September 16, 2002 OCKHAM / ECDL 2002