1. NGDA Architecture Update Greg Janée

2. Greg Janée May 16, 20052 Three motivations Archival has to be cheap & easy –little incentive –no funding Need to archive data semantics –key differentiator from text, audio, video Focus on long-term preservation –need to migrate whole systems

3. Greg Janée May 16, 20053 system databasestorage handle resolver database Typical repository architecture database handle resolver database fragile

4. Greg Janée May 16, 20054 NGDA architecture storage subsystem standard, public data model archival system ADLOAI bulk loader databases, caches, etc. Web access ingest

5. Greg Janée May 16, 20055 Post-NGDA architecture storage subsystem standard, public data model Web

6. Greg Janée May 16, 20056 Storage system requirements Req’s: –associate UUIDs/RIDs with bitstreams –retrieve global/local bitstream by UUID/RID –determine (parent) UUID of any bitstream –list all UUIDs Satisfied by: –any filesystem –tag URIs for UUIDs tag:library.ucsb.edu,2005:identifier

7. Greg Janée May 16, 20057 Archival objects directory UUID component RID UUID

8. Greg Janée May 16, 20058 Archival objects Directory info per component –named relationship/position –format & semantics by UUID references to definitions –fixity: checksum –provenance: isDerivative –policy: mutability –rights Components may be provided by archive itself

9. Greg Janée May 16, 20059 Example USGS DOQQ GeoTIFFFGDC Object x x.tiffx.fgdcx.gif metadata data derived TIFF subtypeOf

10. Greg Janée May 16, 200510 Archives Archive = set of archival objects –no structure –no free-floating bitstreams In anticipation of federation: –associations may cross archive boundaries –archival objects may not

11. Greg Janée May 16, 200511 Object types Content Format definition Semantic definition Provider Organizational structures –collection –series –ingest session

12. Greg Janée May 16, 200512 Archive-provider agreement Defines –common structure of objects to be ingested –necessary validations –associations to other objects –policies, rights, etc. Represents choke point –requires human evaluation

13. Greg Janée May 16, 200513 Deferred functionality Incremental ingest Object revisions Rights 3rd-party access Federation

14. Greg Janée May 16, 200514 Status Starting development now Approach: iterative refinement