Digital Repositories

1
Digital Repositories

• Evolving Standards and Expectations

2
What is a Digital Repository?

• A Digital Library?
• A Digital Archive?
• A Digital Vault?
• A Digital Warehouse?

3
The Bottom Layer

• Many Layered architectures show a Digital
  Repository at the bottom
• JISC
• IMS
• WDVL
• Fedora
• More research projects than you can shake a stick
  at

4
A Layered Architecture
5
Architectural Features

• Search Protocol
• Z39.50, SRW/U XML-Query, DASL
• Harvesting Protocol
• OAI, HTTP, FTP
• Depositing Protocol?
• HTTP, FTP
• Notification Protocol?
• E-mail, RSS

6
Data or Metadata

• Layered architectures usually have metadata in
  the repository and let the metadata describe the
  location and access protocol of the data

7
XML To The Rescue

• Most DR metadata in XML
• MARC-21 (whether XML-MARC or ISO 2709) seen as
  too complex
• No solution provided by DCMI
• Contents vary by community
• LOM, METS, TEI, EAD, ONYX,

8
Operational Features

• Accession Workflow
• Authorization Policy
• Metadata creation/ingest
• Access Mechanism (at least Web Access and
  commonly OAI-PMH)
• De-accession Workflow?

9
An Archivist Perspective

• A trusted location for the preservation of
  digital content
• Data, once accepted,
• Is always available
• Is immutable (barring preservation activities)

10
An Institutional Perspective

• A mechanism for exposing digital assets
• A content management system
• A source of persistent URLs
• A branding mechanism

11
A User Perspective

• Free Diskspace
• A WebServer maintained by someone else
• An e-print service
• A location for course materials

12
Version Control

• Institutional policies will require
  Updates/Corrections
• Creators will want to make changes
• Documents change as part of the accession
  workflow (e.g. e-print service)
• A hole in OAI-PMH?
• A new version is either a replacement for an old
  version
• Or a new document with linkage to an old document

13
Transient Data

• Institutional policies will require the removal
  of materials
• Is all data that goes into a repository worth
  keeping in perpetuity?
• How heavyweight a mechanism do we need to
  determine that?
• Can creators remove their own content?
• What is the cost of just warehousing data?
• Is it cheaper to keep than to think about
  removing?

14
What is a Digital Repository?

• A Pandoras box we cant resist opening
• The salvation of the library?
• The end of the library?