The OCKHAM NSDL Digital Library Services Registry A

The OCKHAM / NSDL Digital Library Services Registry A Distributed Approach To Enable End-to-End Digital Service Resolution emory ▪ notre dame ▪ oregon state ▪ virginia tech

emory ▪ notre dame ▪ oregon state ▪ virginia tech

• Funded by the National Science Foundation • National Science Digital Library Program • 2 Year Project Funding emory ▪ notre dame ▪ oregon state ▪ virginia tech

Goals 1. Create a Registry for all possible Digital Library Services 2. Enable End-to-End Digital Library Service Resolving Sub-Goals 1. Ensure DLSR is Scalable and Redundant 2. Ensure Manageability of DLSR is Scalable 3. Use Existing Standards and Technologies emory ▪ notre dame ▪ oregon state ▪ virginia tech

Use of the DLSR 3 Examples 1. Library Portal Use Case 2. Metasearch Use Case 3. Personal Digital Library emory ▪ notre dame ▪ oregon state ▪ virginia tech

Distributed DLSR • The OCKHAM/NSDL DLSR is Distributed • Many nodes over the network • Scalability • Redundancy • Approach in part based on DNS model emory ▪ notre dame ▪ oregon state ▪ virginia tech

A Brief History of DNS • Hosts. txt file (later just hosts) • ARPAnet started with centralized management • Inter-NIC • Eventually, a more manageable approach was needed • Current Distributed DNS System was created • Allows De-centralized administration • Hierarchical design • Simplifies management • Reduces bandwith, bottlenecks • Reduces duplicate name issue (i. e. . edu, . com, etc. ) emory ▪ notre dame ▪ oregon state ▪ virginia tech

Distributed DLSR • Reasoning much the same as DNS • Similarities and Differences emory ▪ notre dame ▪ oregon state ▪ virginia tech

emory ▪ notre dame ▪ oregon state ▪ virginia tech

emory ▪ notre dame ▪ oregon state ▪ virginia tech

Data Layer Relational Db & OJB • Synchronized • Database Interchangeability • Ease of development Lucene • Fast indexing • “on the fly” indexing • Flexible query engine emory ▪ notre dame ▪ oregon state ▪ virginia tech

Interface Layer Current Interfaces • Struts powered J 2 ee interface • OAICat - OAI-PMH 2. 0 Future Interfaces • SRU/W • Z 39. 50 • Open. URL Output Formats • Html • XML emory ▪ notre dame ▪ oregon state ▪ virginia tech

Clients • • Web browser OAI-PMH Z 39. 50 Any web enabled application. emory ▪ notre dame ▪ oregon state ▪ virginia tech

Network Layer • JXTA provides low level network functionality – Peer identification and discovery – Transport layer • Peer. Manager provides modular application level functionality – Load Management – Client/Server Modules • Main Registry Modules – URL Server – Harvester Client emory ▪ notre dame ▪ oregon state ▪ virginia tech

Using OAI For Propagating Data • A peer can query any other peer and receive an incremental update • Queries are based on the latest record modification date for the peer’s local copy of the set • Subsequent queries will use the new latest record modification date emory ▪ notre dame ▪ oregon state ▪ virginia tech

Hierarchal Network Topology Requirements • Data must propagate to all peers • Compensation for inherent instability of P 2 P networks • Scalable structure • Low overhead • DNS for Digital Library Services emory ▪ notre dame ▪ oregon state ▪ virginia tech

Put the pieces together emory ▪ notre dame ▪ oregon state ▪ virginia tech

OCKHAM Future • Expand the DLSR Community and Use • Explore and build DLSR-aware tools and services • Prototype semi-automated creation of DL’s emory ▪ notre dame ▪ oregon state ▪ virginia tech

Further Information OCKHAM Website – http: //ockham. org Martin Halbert, Emory – mhalber@emory. edu Jeremy Frumkin, Oregon State University – jeremy. frumkin@oregonstate. edu emory ▪ notre dame ▪ oregon state ▪ virginia tech