INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS ERPANET: OAIS Seminar Copenhagen - København 28th November 2002 Introducing the OAIS Model _________________________________ David Holdsworth

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS u Curl Exemplars in Digital ARchiveS u Collaborative project for libraries u Funded by HEFCE/JISC u Oxford, Cambridge and Leeds CEDARSCEDARS C A Mi L E O N u CAMiL EON u Creative Archiving at Michigan and Leeds Emulating the Old on the New u Collaborative project on emulation u Funded by NSF/JISC

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS Overview - History u Digital beginnings - lost  u Science goes digital u Mass Storage Reference Model u Need for abstraction u Media Obsolescence

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS u Generic model for systems that keep data long time. u Threats to long-term storage u Assumptions about the future u Structure of the document u OAIS concepts Overview - OAIS

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS u Earliest digital objects were software for early machines. u Could have kept but did not u Scientific data from 60s often digital u not all has survived u IEEE Conference is now 20 years old u Mass Storage Reference Model became focussed on hardware u data is abstract u Gradual realisation in 90s History

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS u specifies style not detail u conforming archives will have u conforming overall architecture u conforming operational procedures u conforming archives are not required to have u interchangeable storage volumes OAIS is a Generic Model

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS Threats to long-term storage - Hardware u none of today’s hardware will be commonplace u that which exists probably won’t work. u none of today’s software will be commonplace u loss of knowledge about data

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS Assumptions about the future u The concept of a sequence of bytes will still exist u We might still understand the ASCII character set u We will have a representation of alpha-numeric characters u We will not understand Word6, GIF, Excel u We will be unable to read any of today’s media u Storage densities will increase

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS OAIS standards document u §1 Introduction — much formal definition u §2 OAIS concepts — read first u §3 OAIS responsibilities — read second u §4 Detailed models — in depth u §5 Preservation perspectives — rationale u §6 Archive interoperability — taxonomy

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS OAIS concepts  Representation Information (RI) u how the intellectual content is represented u Preservation Description Information (PDI) u Provenance, Rights, etc. u Designated community u know for whom you are doing digital preservation

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS u media lifetime u need to refresh is unavoidable u ingest u the process of taking data into the archive u package u digital information divorced form any particular medium (usually) u archival storage u preserving the bytes OAIS concepts (cont)

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS Representation Information (RI) u how the intellectual content is represented u how to extract meaning from a stream of bytes u made up of linked nodes of archived objects — Representation Net u Assume knowledge of Designated Community

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS RI can even represent physical objects Moon Rock

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS OAIS Responsibilities u Negotiate for and accept appropriate information from information Producers. u Obtain sufficient control of the information provided to the level needed to ensure Long-Term Preservation. u Determine, which communities should become the Designated Community. u Ensure that the information to be preserved is Independently Understandable to the Designated Community.

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS OAIS Responsibilities (cont) u Follow documented policies and procedures which ensure that the information is preserved against all reasonable contingencies, and which enable the information to be disseminated as authenticated copies of the original, or as traceable to the original. u Make the preserved information available to the Designated Community.

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS Functional model Figure 4-1: OAIS Functional Entities Detailed models

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS Detailed models Figure 4-10: Information Object Information model

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS Representation Information Object Figure 4- 11

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS Archive interoperability Preservation perspectives “This subsection addresses various practices that have been, or might be, used to preserve digital information and to preserve access services to digital information.” Provides a taxonomy of types of interoperability, and recommendations for achieving interoperability.

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS Information Package Figure 4-13: Information Package Contents

INFORMATION SYSTEMS SERVICES UNIVERSITY OF LEEDS ERPANET: OAIS Seminar Copenhagen - København 28th November 2002 ed Introduc ed the OAIS Model _________________________________ David Holdsworth