ISO/CCSDS Open Archival Information System (OAIS) Reference Model

1. ISO/CCSDS Open Archival Information System (OAIS) Reference Model D Giaretta Chairman of CCSDS Panel 2 Rutherford Appleton Laboratory

2. What are ‘Open Archival Information Systems’ • OPEN • Reference Model standard(s) being developed with participation open to all • Clearly defined interfaces • (i.e. Does not imply uncontrolled access) • ARCHIVAL INFORMATION SYSTEM • Hardware, software and people who are discharging their responsibilities to acquire, preserve and disseminate information

3. ... • INFORMATION • Any type of knowledge that can be exchanged • Independent of the forms (i.e. Physical or digital) used to represent the information • OAIS Archive • one that meets the minimum requirements given later • need for CERTIFICATION procedure

4. CCSDS Panel 2 involvement • ISO Technical Committee (TC) 20: Aircraft and Space Vehicles, and its Sub-Committee (SC) 13: Space Data and Information Transfer Systems • Promote standards for “archiving” space data

5. ...Panel 2 • Proposal made to Consultative Committee for Space Data Systems and ISO TC20/SC 13 • Develop a ‘Reference Model’ to establish common terms and concepts • Ensure broad participation, including traditional archives • Focus on data in electronic forms, but recognise that other forms exist in most archives • Follow up with additional archive standards efforts as appropriate

6. Why CCSDS Panel 2? • Close association between ISO TC20/SC13 and CCSDS • The archive work complements other Panel 2 work • Space Data is extremely expensive to obtain. Long term preservation and sharing is very important - hence the importance of archiving to CCSDS members • It is not possible to distinguish between information obtained from space and that obtained by other means

7. Timescales • Panel 2 will produce the ISO Draft International Standard (DIS) for the OAIS by May 1998 • The DIS will be submitted to the ISO process • Work will follow to produce related standards based on the Reference Model

8. Related work • Work led by NASA members of CCSDS • Many US workshops involving industry, National Archive, military etc. • Workshop held in France • Several International workshops • Details available on the WWW http://bolero.gsfc.nasa.gov/nost/isoas

9. Rationale • Growth in computer power, network bandwidth leads to increasing use of electronic forms for information - e.g. Digital data • Many organisations are now performing an “archival” task • Preserving digital data for the long term is more difficult than for paper • hardware and software becomes obsolete (years not decades)

10. ‘Long-Term’ Archive Problems • The archived information must be useable by consumers who are separated in time, distance and background from the producers • producers no longer available • cannot answer questions on ad-hoc basis • producers’ software not supported - may be obsolete • knowledge captured by the software becomes unavailable • documentation is lost over time

11. ...problems • the user community will change over time • new community will be unfamiliar with the background to the information • may use different analysis environment • may want to combine information from many sources

12. .......problems • The archive will change over time • migration to new technology - hardware/software • may require reorganisation of information • Possible changes in implicit relationships • migration to different institutions • Possible changes to management, data structure, file format

13. Reference Model • A Reference Model is needed to provide a common framework for discussion & description • A major aim is to facilitate a much wider understanding of what is required to preserve information for the long term • Facilitates description and comparison of archives • Provides a basis for further standardisation • help broaden the market for commercial providers

14. ...Reference Model • We are particularly concerned with Long-Term Preservation of digital information • long term is long enough to be concerned about changing technologies • not just bit preservation • starting point for model addressing non-digital information

15. ......Reference Model • But this work is also of use for “Short-Term archives” because • technological change is rapid (years, not decades) • the short-term archive may eventually hand information over to another, longer-term, archive

16. OAIS Concepts Environment Information Responsibilities

17. Archives - simplest view ARCHIVE Consumer Producer Management

18. Producer Result set Submission Information Package C Nill OAIS queries Presentation by P Mazal orders Consumer Dissemination Information Package

19. OAIS Concepts • Environment • Information • Responsibilities

20. Information Package Information Package Content Information Supporting Information Primary focus of archival preservation Needed for long-term preservation

21. Content Info is itself understandable by some designated community e.g. the information in a file could be a physical object needs Representation Information e.g. to give meaning to a bit sequence in a file Supporting Information e.g. how the Content Info. came into being who has held it how it relates to other information how its integrity is ensured also has Representation Information Information Package components

22. Variants of Information Package Information Package Archival Information Package Dissemination Information Package Submission Information Package Internal to OAIS Support Info called Preservation Information Sent by OAIS to Consumer Sent by Producer to OAIS

23. Archival Information Package Archival Information Package Archival Information Collection Archival Information Unit Info having all qualities needed for long-term preservation of a designated information object

24. Preserving Description Information(PDI) Preserving Description Information • Fixity Reference Provenance Context Catalogue Information

25. PDI Definition Reference Contains one or more Content Information identification-system value sets (e.g. URL, ISBN, title/author/publisher) Provenance Documents history, chain of custody, of Content Information

26. Context Documents relationships of Content Info. to environment Technical (e.g. Mapping to physical media) Social (e.g. Why it was created) Catalogue Optional info extracted from Content Info - to be used in searches ...PDI definition

27. Fixity Describes mechanisms (authentication) used to ensure Content Information has not been altered in an undocumented manner. Encryption, digital signature, physical security, time stamping etc. .......PDI definition

28. Content Information Content Information 1+ interpreted using Data Object interpreted using 1+ Representation Information Physical Object Digital Object 1+ Bit Sequence

29. Representation Information Representation Information Structure Layer Information Semantic Layer Information Understood Using

30. ...Representation Information • Representations will be discussed in following presentation by P Mazal

31. OAIS Concepts Environment Information Responsibilities

32. OAIS Responsibilities • Negotiates & accepts Submission IPs • Determines communities which need to be able to understand Content Information • Ensures information to be preserved is understandable to designated communities • Assumes sufficient control of info. to be able to ensure long-term preservation • Follows policies & procedures to ensure information is preserved • makes the information available to the designated communities in appropriate forms

33. Negotiates and Accepts SIPs • Establishes criteria to determine types of information to be accepted • uses conceptual SubmissionInformation Package (SIP) • separates Content Info. from Preserving Description Info.

34. Determines Designated Consumer Communities • Designated consumer community determines the Submission Information Package • Concern about evolution of the Designated Community

35. Ensures Information is Independently Usable • Usable by the designated community • Complex topic

36. Assumes Sufficient Control for Preservation • Must be able to change the data structures as necessary • Control changes by others

37. Follows Established Preservation Policies & Procedures • Transformations and migrations - tracable back to original information • Long-term technology evolution plan needed

38. Makes the information available • Makes the IP’s visible and available to consumers • user selections/searches • variety of distribution media

39. OAIS Models • Functional Model, High Level Data Flows • Transformations • Migration

40. Functional Model of OAIS Data Management Access Ingest Producer Consumer Dissemination Storage Common Services Administration Management

41. Inter-process communications name services temporary storage allocation exception handling security directory services OAIS Common Services - examples

42. Provides the services to accept and validate input and prepare for storage and management Scheduling Staging Review Conversion Extract Metadata from SIP Transfer Initiation (to storage) Ingest Reporting INGEST

43. Services and function for storage and retrieval of AIP and component data objects Transfer Receiving (from Ingest) Hierarchy Management Physical Migration Error Checking Backup Duplication Storage Reporting STORAGE

44. Services and functions for populating, maintaining and querying wide variety of metadata Report Request Report Generation Update Metadata Maintenance Database Administration Data Management Reporting DATA MANAGEMENT

45. Manages all the system activities Acquisition Configuration Management Physical Access Control Planning and Scheduling Monitoring Accounting Customer Service Data Engineering ADMINISTRATION

46. Supports user in determining existence, description, location and availability of information of interest Access Control Overview/Browse Query Retrieve Manipulate Display Order Advanced Development Access Reporting ACCESS

47. Services and function to fulfill requests for data Receive data orders Monitor orders Retrieve data Retrieve metadata Generate ancillary data Format data Off-line delivery On-line delivery Confirm delivery Delivery Reporting DISSEMINATION

48. ...OAIS Models • Functional Model, High Level Data Flows • Transformations • Migration

49. Transformations • In Producer • from producer’s internal format to SIP • In Ingest • create AIP and catalogue information from SIP • In Storage & Data Management • e.g. to DBMS or HFMS • In Access • into finding-aids • In Dissemination • to form suitable for consumer

50. Results Sets Additional Metadata Queries Data Management Access Catalogue Metadata Ingest SIP Producer Consumer Catalogue Metadata Dissemination Dissemination IP Storage Archival IP CAP AIP CAP Orders Common Services Administration Management