ogf 2007 presentation-1 · • transparent migration to new media. open repositories 2007, san...

Open Repositories 2007, San Antonio, 23 Jan. 2007 1

Funded by:

© AHDS

Grid activities at the Arts and Humanities Data Service

Mark Hedges

Arts and Humanities Data ServiceKing’s College London

Funded by:

© AHDS

OGF 20, Manchester, 7 May 2007

Overview• What is the AHDS?• Grid applications at the AHDS• Next steps


Funded by:

© AHDS

What is the Arts and Humanities Data Service?

Funded by:

© AHDS


What does the AHDS do?

• Preserves and distributes digital resources for research and teaching in arts and humanities subjects

• These resources are free for educational and private use

• Generally available online


Funded by:

© AHDS


How is the AHDS Organised?

• Established in 1996• Evolved considerably over 10 years• Managing Executive• Geographically distributed centres for

particular disciplines: History, Visual Arts, Performing Arts, Archaeology, Literature/Languages/Linguistics,

• Virtual centres for other disciplines

Funded by:

© AHDS


Collections

History

Archaeology

Literature/Linguistics

Visual Arts

Performing Arts

• Highly diverse in terms of type and size

• Images, text, databases, video, sound, multimedia

•Complex internal structures

•Require discipline-specific knowledge to process

• increased acquisition rate


Funded by:

© AHDS


Museum of London Archaeological Archive

New Survey of London Life and Labour, 1929-1931

Corpus of Romanesque Sculpture in Britain

Imperial War Museum

Electronic Corpus of Tyneside English

Funded by:

© AHDS

Grids and the AHDS


Funded by:

© AHDS


Grid activities at the AHDS

• DARIAH• Preservation environment• Repositories and grids

Funded by:

© AHDS


Digital Preservation

“Ensuring the usability of a digital resource through changing technological regimes with a minimum loss of the resource’s intellectual content.”

AHDS Preservation Glossary


Funded by:

© AHDS


AHDS preservation approach• Complies with OAIS (Open Archival

Information System) reference model• Preservation actions on ingest

- Capture preservation metadata set- Format normalisation

• Post-ingest: monitoring format/tool obsolescence and format migration

Funded by:

© AHDS


Data grid based preservation• First approach - based on Storage

Resource Broker• Virtualisation of storage• Distributed across heterogeneous

resources (within AHDS and elsewhere)• Multiple replicas• Metadata associated with data object• Transparent migration to new media


Funded by:

© AHDS


Drawbacks• Difficult to integrate specialised

preservation requirements• Implemented as external client code• Metadata limited in scope (compared to

what we want to store for our complex objects)

Funded by:

© AHDS


Enhanced approach• Based on iRODS (Rule Oriented Data

System)• Data management or preservation

actions encoded as rules built up from atomic services

• Rules integrated with system, yet easily changeable


Funded by:

© AHDS


Simple example • In the preservation archive, files are

periodically checked for fixity and repaired as necessary

• Define a rule set implementing this, with multiple possibilities for corrective action.

• An advantage: the services can access more complex metadata held in external digital repository systems.

Funded by:

© AHDS


Nature of humanities research data

• “Hard” sciences – requirements derived from need for fast access to large distributed data sets, simulations

• Humanities – complexity and context dependency of research material


Funded by:

© AHDS


Digital repositories• Need to represent humanities digital content

so as to reflect its complexity and context.• So: Store using flexible digital repository

systems (Fedora at AHDS). • Need seamless integration between these

highly structured repositories.• So: Integration repository software with grid

middleware.

Funded by:

© AHDS


Repository-Grid IntegrationTwo broad approaches:• Grid as virtualised distributed storage. • Repositories as data resources on grid.


Funded by:

© AHDS


Grid storage for Fedora• Fedora has been integrated with SRB,

providing virtualised storage. • Currently looking at iRODS integration.• Will be able to make use of the complex

metadata stored within Fedora (for discovery as well as preservation).

Funded by:

© AHDS


Fedora repositories as grid resources• Use grid technologies to allow access to

distributed Fedoras belonging to different administrative domains.

• Registries to store information about repositories and contents.

• Grid AuthN and AuthZ mechanisms providing uniform access.

ogf 2007 presentation-1 · • transparent migration to new media. open repositories 2007, san...

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