Fedora Commons:Introduction and Update

Swedish National Library

June 24, 2008

The Flexible Extensible Digital Repository Architecture

• A repository management system• A foundation for many information

management applications• Designed to make data “durable” over the

long term• A set of abstractions that can be used to

represent different kinds of data

The Fedora Project

• Developed at Cornell under an NSF grant• UVA Library re-interpreted the architecture

and created the first practical implementation• 3 year project funded in 2001 by Andrew W.

Mellon Foundation to create open-source system

• Another 3 years of development funded by Mellon in 2004

Fedora Commons, Inc.

• 501-(c)3 private, non-profit company• 4-year project funded by Moore Foundation to

become self-sustaining• Continuing software development• Moving towards community-based software

development• Establishing “solution councils” for the

development of solution bundles.

Scholarly and Scientific Collections

Preservation and Archiving

Education, Knowledge Spaces

The world we work in…

Data Curation, Linking, Publishing

blog and wiki

and more …

127 Current Known Users

• Consortia – 5• Corporations – 12• Government agencies – 2• IT- Related Institutions – 6• Medical Centers and Libraries – 4• Museums and Cultural Organizations – 4• National Libraries and Archives – 16• Professional Societies – 2• Publishing - 4• Research Groups and Projects – 11• Semantic and Virtual Library Projects - 6• University Libraries and Archives - 55

7 Known Vendors and Integrators:

• Acuity Unlimited• Atos Origin, France• CARE Affiliates• Fitz Karlsrhue• MediaShelf, LLC• Sun Microsystems• VTLS

Abstract Data M anage me nt(F e dora CommonsSe rv ice F rame work)

Preservationand Archiv ing

Solutions

Data CurationSolutions

eResearchSolutions

PublishingSolutions

TapeLib rar ie s

Hone ycomb

RAID array

A data object is one unit of content.

Persistent ID (PID)

System Metadata

Policies

Relationships

Local Content

Datastreams managedby the system

Datastreams for thecomponents of the content

Datastream Types

• Inline XML : content in the FoXML object• Managed Content : content is managed by

the repository• Externally Referenced: URL of remote

content is in the FoXML object• Re-directed Referenced: external but content

is not disseminated through Fedora

Datastream Characteristics

• Can have any number and multiple types in the same object

• Versioned automatically by default• Checksums automatically by default• Formal identifier• Alternate identifiers• Audit trail maintained about all datastream

actions

Relationships Among Objects

• Describes adjacency relationships among objects

• RDF data of the form:

PID – typeOfRelationship – relatedObjectPID• Can used to assemble aggregations of

objects• Can build graphs of relationships to feed into

user interfaces

Optional Object Behaviors

• Data objects can have different views or transformations

• Sets of abstract behaviors that different kinds of objects can subscribe to

• Corresponding sets of services that specific objects can execute

• The business logic is hidden behind an abstraction

General Im age Object

JPEG2000 Im age Object

Persistent ID(PID)

SystemMetadata

thumbnail image file

med res. image file

high res. image file

max res. image file

Persistent ID(PID)

SystemMetadata

JPEG200im age file

Service Description

Service M echanismfor General Im age Objects

ServiceM echanismfor JPEG2000 Im age Objects

get-thum bnail-sized-im age

get-m ed-sized-im age

get-h igh-res-im age

get-m ax-sized-im age

get-thum bnail-sized-im age

get-m ed-sized-im age

get-h igh-res-im age

get-m ax-sized-im age

get-sm allest-JPEG2000-size

get-m idrange-JPEG2000-size

get-h igh-res-JPEG2000-size

get-m ax-JPEG2000-size

Content Models

• Create classes of data objects• Expressed as Cmodel objects• A Cmodel object defines the number and

types of data streams for objects of that class• A Cmodel object binds to service object to

enable appropriate behaviors to be inherited by data objects

Persistent ID (PID)

Service DefinitionMetadata

SystemMetadata

DatastreamsCmodel Object

Persistent ID (PID)

Service BindingMetadata (WSDL)

SystemMetadata

Datastreams

WebService

service contract

service

subscriptio

n

data contract

Persistent ID (PID)

RDF data

Datastreams

System Metadata

Service Mechanism Object

Service Definition Object

Persistent ID (PID)

System Metadata

Datastreams

Data Objects

Other components include:- Parameter values used by the method- Datetime stamp for earlier version

A behavior call has the form:

Object PID + BDef Name + Method Name

Object Representing Aggregations

• Creating parent objects for complex resources

• Representing explicit collections• Representing implicit collection• Creating digital surrogates for physical

entities

Fedora Repository ServiceGSearch

OAI

DirIngest

SimpleJMS

The Fedora Service Framework

Preserve

These are the core servivce components we distribute.

Solution Councils

• Community group that creates and maintains the vision for solution bundle in an area

• Led by a “champion”• Small group that gets things done• Gathers resources to create software for

solution• Coordinates development with the FC

Architecture Council

Solution Areas

• Preservation and Archiving – Ron Jantz, from Rutgers

• Data Curation – Sayeed Choudry, from Johns Hopkins University

• Publishing – Rich Cave, from PLOS• Integration Services – Matt Zumwalt from

MediaShelf, LLC

Other Possible Community Groups

• Other software development groups• News and Publications Outreach group that

works with our Communications Director• Issue/advocacy groups that work on

standards important to the community

Collaboration Discussion with DSpace

• Conversation has just begun• DSpace will experiment with Fedora in Google

Summer of Code, 2008• Possibilites:

– Dspace 2.0 expresses data model using Fedora objects (Dspace could be the “reference” IR solution bundle)

– Shared development of services used by both– Sharing administration– ????

http://www.fedora-commons.org/