1. © 2006 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice DSpace Architecture Progress and Ideas Dr. Robert Tansley Digital Media Systems Department HP Labs

2. 1 February 2006DSpace User Group Meeting, Sydney2 Overview DSpace development process Architectural Progress Strawman Roadmap Future architecture evolution

3. 1 February 2006DSpace User Group Meeting, Sydney3 DSpace Development Process

4. 1 February 2006DSpace User Group Meeting, Sydney4 DSpace development Decentralised open source development No central control by HP or MIT Overall direction comes from consensus of contributors

5. 1 February 2006DSpace User Group Meeting, Sydney5 DSpace development

6. 1 February 2006DSpace User Group Meeting, Sydney6 Committer Group 7 Individuals from different organisations Actively seeking more committers − willing to donate time to release management, bug fixing, evaluating community contributions Development, maintenance, documentation of DSpace remains community responsibility − Committers are gatekeepers, coordinators

7. 1 February 2006DSpace User Group Meeting, Sydney7 Communication Mechanisms DSpace-general − High-level discussion, announcements DSpace-tech − Technical discussion and support DSpace-devel − Those developing the DSpace system DSpace Wiki: wiki.dspace.org − Publicly writeable Web site − Information about projects, developments, proposals, ideas, documentation, early prototype code, translations

8. 1 February 2006DSpace User Group Meeting, Sydney8 Please contribute! Share early, share often E-mail the dspace-tech list with any modifications you’re making − Before you’ve made them – someone may save you the trouble! Describe projects, proposals, developments and solicit feedback as early as possible − Maximises chances of integration and impact − Encourage collaborations − Avoid duplication of effort Share prototypes on the Wiki

9. 1 February 2006DSpace User Group Meeting, Sydney9 Working Groups A way to accelerate progress in a particular area Form small, focussed, inter-organisation teams − Somewhere between “one organisation/institution” and “the entire DSpace community” Specific goals and timeline First working group: Manakin XML UI framework − Texas A&M, Rice

10. 1 February 2006DSpace User Group Meeting, Sydney10 Architectural Progress

11. 1 February 2006DSpace User Group Meeting, Sydney11 Current architecture

12. 1 February 2006DSpace User Group Meeting, Sydney12 DSpace architectural evolution Initial architecture designed in 2001 In March 2004, 3 main issues architectural identified Storage for preservation User interface framework Modular

13. 1 February 2006DSpace User Group Meeting, Sydney13 Plug-ins New plug-in mechanism in 1.4 Allows selection of behaviours and implementations from configuration Interface is specified Configuration can specify − Single plug-in to use − Set of named plug-ins, allowing behaviour to be selected at runtime − Sequence of plug-ins, enabling simple pipelines, stackable

14. 1 February 2006DSpace User Group Meeting, Sydney14 Add-on mechanism Add-on mechanism to facilitate development and maintenance of additional functionality − Reduce complexity of core DSpace code Updated build process Add-ons must have separate code, use separate DB tables Are versioned separately; can be certified compatible with 1.x, 1.y etc

15. 1 February 2006DSpace User Group Meeting, Sydney15 Plug-ins vs add-ons Plug-ins add/change functionality of some core feature − E.g. ingester plug-ins for METS, MPEG-21 DIDL, IMS-CP − Authentication (password, LDAP, X509) − Media filters Add-ons are new functionality − Researcher pages − E-theses features

16. 1 February 2006DSpace User Group Meeting, Sydney16 Messaging Asynchronous messages sent from one system component to another (subscription model) − E.g. “Item update” message, subscribed to by Lucene indexing module Decoupling − To react to item updates and other events, don’t need to modify core code Improving performance at scale − E.g. during batch import, indexing can happen asynchronously and at a lower priority Helps enable clustering servers

17. 1 February 2006DSpace User Group Meeting, Sydney17 UI Framework Manakin XML UI framework built on Cocoon Modularises UI Enhances UI customisability No need to touch Java/JSP code

18. 1 February 2006DSpace User Group Meeting, Sydney18 Other recent and upcoming architecture improvements Plug-in SIP and DIP support Plug-in metadata crosswalks − Java or XSLT SRB storage option Federation via OAI-PMH Lightweight network interface

19. 1 February 2006DSpace User Group Meeting, Sydney19 Storage: AIP metadata AIP metadata stored as METS bitstream in existing bitstream storage − Transactional − Bitstreams have info: URI IDs − Enables checksum checking, format tracking, media filters etc − Rich METS structure enables different kinds of metadata at different levels (e.g. item, bitstream)

20. 1 February 2006DSpace User Group Meeting, Sydney20 A DSpace AIP (notice it’s all Bitstreams)

21. 1 February 2006DSpace User Group Meeting, Sydney21 Strawman Roadmap 1.4 (Winter ’06) − Plug-ins, add-on mechanism, plug-in SIP/DIP support 1.5 (Summer/fall ’06) − Messaging framework − Add METS AIP metadata to data model; info: URIs for bitstreams − Start making parts of the system add-ons 1.6 (Winter ’07) − Manakin becomes main UI framework; start modularising UI − Expose richer METS structure via content mgmt component

22. 1 February 2006DSpace User Group Meeting, Sydney22 An evolving architecture

23. 1 February 2006DSpace User Group Meeting, Sydney23

24. 1 February 2006DSpace User Group Meeting, Sydney24 Some questions Where should the DSpace community focus? − Narrow or broad? End user user interfaces? Administration/collection management interfaces? Service-oriented architecture? Which services? Participate in defining standards?