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Kort introduktion til OAIS

Open

Archival

Information

System

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Program

DEL 1• OAIS• Arkivbegrebet• Informationsbegrebet• Processerne• Relaterede standarder

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Historie

• NASA National Space Science Data Center er NASAs første digitale arkiv – siden 1966

• Consultative Committee for Space Data Systems (CCSDS) har deltaget i ISO-arbejde siden 1990

• ”Blue book” fra CCSDS i 2002• Nu en CCSDS ”Recommendation” og en

ISO Standard

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OAIS

DEKLARATION:------------Informationsbegreb 40%Procesbeskrivelser 40%Interfaces 10%Diverse + fyldstoffer 10%

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En ”Reference model”

• Abstrakt – top-down

• Forstå sammenhænge – arkivarer, ledere, brugere

• Rammemodel for yderligere standardisering

• Fokus på elektroniske arkivalier, men også ikke-elektroniske

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Hvem bruger det?

• ”Alle”

• Digitale biblioteker

• Papirarkiver

• Videnskabelige datacentre

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Hvad er et Arkiv?

• OAIS: Et arkivs hovedopgave er at bevare en samling information og gøre denne tilgængelig i en forståelig og brugbar form for et udpeget ”Designated Community” (”udpeget målgruppe” ?)

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Model View of an OAIS Environment

Producer is the role played by those persons, or client systems, who provide the information to be preserved

Management is the role played by those who set overall OAIS policy as one component in a broader policy domain

Consumer is the role played by those persons, or client systems, who interact with OAIS services to find and acquire preserved information of interest

OAIS(archive)

Management

Producer Consumer

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Open Archival Information System:Six Functional Entities

SIP = Submission Information Package

SIP

DIP

Administration

PRODUCER

CONSUMER

queriesresult sets

MANAGEMENT

Ingest Access

DataManagement

ArchivalStorage

DescriptiveInfo.

Preservation Planning

orders

AIP

AIP = Archival Information Package

DIP = Dissemination Information Package

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OAIS Information Definition

Information is always expressed (i.e., represented) by some type of data

Data interpreted using its Representation Information yields Information

Information Object preservation requires clear identification and understanding of the Data Object and its associated Representation Information

DataObject

InterpretedUsing its

RepresentationInformation

Yields

InformationObject

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Information Package Definition

An Information Package is a conceptual container holding two types of information

– Content Information– Preservation Description Information (PDI)

PreservationDescriptionInformation

ContentInformation

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Information ObjectInformation

Object

RepresentationInformation

1+Interpretedusing1+Data

Object

PhysicalObject

DigitalObject

BitSequence

1+

Interpretedusing

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Recursive Nature ofRepresentation Information

Structure Information Semantic Information Other Representation

Information

Interpreted using

SemanticInformation

StructureInformation

Other

RepresentationInformation

adds meaning to

RepresentationInformation

*

1

*

1

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Types of Information Used in OAIS

InformationObject

ContentInformation

PackagingInformation

PreservationDescriptionInformation

DescriptiveInformation

. . .

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Content Information

The information which is the primary object of preservation An instance of Content Information is the information that an archive

is tasked to preserve. Deciding what is the Content Information may not be obvious and

may need to be negotiated with the Producer The Data Object in the Content Information may be either a Digital

Object or a Physical Object (e.g., a physical sample, microfilm)

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Preservation Description Information

• Provenance Information– Describes the source of Content Information, who has had custody

of it, what is its history

• Context Information– Describes how the Content Information relates to other information

outside the Information Package

• Reference Information– Provides one or more identifiers, or systems of identifiers, by which

the Content Information may be uniquely identified

• Fixity Information– Protects the Content Information from undocumented alteration

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PDI Examples Content

InformationType

Reference Provenance Context Fixity

SpaceScience Data

Object identifier Journal reference Mission,

instrument, title,attribute set

Instrument description Processing history Sensor description Instrument Instrument mode Decommutation map Software interface

specification

Calibration history Related data sets Mission Funding history

CRC Checksum Reed-Solomon

coding

DigitalLibrary

Collections

Bibliographicdescription

Persistentidentifier

For scannedcollections: metadata about the

digitisation process pointer to master

version For born-digital

publications: pointer to the digital

original Metadata about the

preservation process: pointers to earlier

versions of thecollection item

change history

Pointers to relateddocuments inoriginalenvironment at thetime of publication

Digitalsignature

Checksum Authenticity

indicator

Software Package

Name Author/Originator Version number Serial number

Revision history License holder Registration Copyright

Help file User guide Related software Language

Certificate Checksum Encryption CRC

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Descriptive Information

Contain the data that serves as the input to documents or applications called Access Aids.

Access Aids can be used by a consumer to locate, analyze, retrieve, or order information from the OAIS.

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Packaging Information

Information which, either actually or logically, binds and relates the components of the package into an identifiable entity on specific media

Examples of Packaging Information include tape marks, directory structures and filenames

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OAIS Archival Information PackageArchival

InformationPackage (AIP)

ContentInformation

PreservationDescriptionInformation

(PDI)e.g., • Hardcopy document

• Document as an electronic file together with its format description • Scientific data set consisting of image file, text file, and format descriptions file describing the other files

e.g., • How the Content Information came into being, who has held it, how it relates to other information, and how its integrity is assured

PackagingInformation

PackageDescription

further described by

delimited byderived from

e.g., How to find Content information and PDI onsome medium

e.g., Informationsupporting customersearches for AIP

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AIP Types Archival Information Unit (AIU)

contains a single Data Object as the Content Object

Archival Information Collection (AIC) contains multiple AIPs in its Content Object– Each member of an AIC is

an AIP containing Content Information and PDI

– The AIC contains unique PDI on the collection process

ArchivalInformation

Package

ArchivalInformation

Unit

ArchivalInformationCollection

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Package Descriptions and Access Aids

Package Descriptions are needed by an OAIS to provide visibility and access to the OAIS holdings

Package Descriptions contain 1 or more Associated Descriptions which describe the AIP Content Information from the point of view of a single Access Aid

Some example of Access Aids Include:– Finding Aids - assist the consumer in locating information of interest– Ordering Aids - allow the consumer to discover the cost of and order

AIUs of interest– Retrieval Aids - enable authorized users to retrieve the AIU described by

the Unit Descriptor from Archival Storage

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Information Model Summary Presented a model of information objects as containing

data objects and representation objects Classified information required for Long-term archiving

into 4 classes: Content Information, PDI, Packaging Information and Descriptive Information

Described how these classes would be aggregated and related in an AIP to fully describe an instance of Content Information

Presented information needed for Access, in addition to that needed for Long-term Preservation

Put the Access oriented structures in the context of the other data needed to operate an OAIS

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Detailed Models

Functional View

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General Principles

Highlight the major functional areas important to digital archiving

Use functional decomposition to clarify the range of functionality that might be encountered– Don't decompose beyond two levels to avoid becoming too

implementation dependent– Provide a useful set of terms and concepts– Do not imply that all archives need to implement all the sub-

functions Identify some common services which are likely to be

needed, and are assumed to be available, as underlying support

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Open Archival Information System:Six Functional Entities

SIP = Submission Information Package

SIP

DIP

Administration

PRODUCER

CONSUMER

queriesresult sets

MANAGEMENT

Ingest Access

DataManagement

ArchivalStorage

DescriptiveInfo.

Preservation Planning

orders

AIP

AIP = Archival Information Package

DIP = Dissemination Information Package

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Functional Entities In An OAIS Ingest: This entity provides the services and functions to accept Submission

Information Packages (SIPs) from Producers and prepare the contents for storage and management within the archive

Archival Storage: This entity provides the services and functions for the storage, maintenance and retrieval of Archival Information Packages

Data Management: This entity provides the services and functions for populating, maintaining, and accessing both descriptive information which identifies and documents archive holdings and internal archive administrative data.

Administration: This entity manages the overall operation of the archive system

Preservation Planning: This entity monitors the environment of the OAIS and provides recommendations to ensure that the information stored in the OAIS remain accessible to the Designated User Community over the long term even if the original computing environment becomes obsolete.

Access: This entity supports consumers in determining the existence, description, location and availability of information stored in the OAIS and allowing consumers to request and receive information products

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Ingest Data Flow DiagramNESTOR/Grunberger

Rev f, 2-25-99

AIPSIPSIP

AIP

AIP

Descriptive info.

Co-ordinate Updates

Generate Descriptive

Info

Archival Storage

Data Management

Quality Assurance

Report request

ReportAdministration Format & doc. stds.

Receive Submission

Descriptive info.

GenerateAIP

Storage confirmation

[Updated] SIP

SIP, AIP Report

SIP

QA results

PRODUCER

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Digital Migration Approaches • Four primary types of digital migration in

response to motivators, ordered by increasing risk of information loss:– Refreshment

• Media replacement with no bit changes

– Replication• No change to Packaging Information or Content Information

bits

– Repackaging• Some bit changes in Packaging Information

– Transformation• Reversible: Bit changes in Content Information are reversible

by an algorithm• Non-reversible: Bit changes in Content Information are not

reversible by an algorithm

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Relaterede standarder(Generelt)

• International Council on Archives: Handbook No. 7, 1988: Dictionary of Archival Terminology: English and French… og 5 andre sprog

• På vej fra Research Libraries Group (RLG): Certificeringskrav for arkiver

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Schema for metadata

• For biblioteker: METS, MARC, MODS, MIX, TEI, EAD, ONIX

• For arkiver: OAI-MARC m.fl., men

• Mange er ”extensible”

• Ingen er rigtig slået igennem

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Relaterede standarder(Representation Information)

• EAST: ISO standard for databeskrivelse (syntaktisk beskrivelse)

• Data Entity Dictionary Specification Language (DEDSL) – Abstract Syntax (semantisk beskrivelse)

• ISO-standarder fra Technical Committee (TC) 211: Referencemodel for geo-data

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Relaterede standarder(Ingest)

• CCSDS, 2004: Producer-Archive Interface Methodology Abstract Standard

• På vej fra CCSDS: XML-baserede SIP’er

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Mulige fordele ved OAIS

• En anerkendt ”Best Practice” for arkiver

• Lettere at kommunikere internationalt

• Lettere at kommunikere med ikke-arkivpersonale

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Idéer 1

• Tilpasse sprogbrug og tankegang til OAIS så vi bedre kan kommunikere og i øvrigt støtte os til OAIS’ informationsbegreb og processer.

• Tilpasse vores danske begrebsapparat til OAIS.

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Idéer 2

Justere vores informationsbegreb og:• Systematisk udpege målgruppen for nye

afleveringer• Lade målgruppen danne grundlag for krav

til Representation Information og Preservation Description Information (”kontekst”) i hvert enkelt tilfælde

• Gruppere metadata ifølge OAIS

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Idéer 3

Få commitment til OAIS fra hele RA

• Et OAIS arkiv skal have ”custody” over hele arkivaliet – dette inkluderer f.eks. søgebeskrivelsen i DAISY

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Idéer 4

• Gennemgå vores processer i forhold til OAIS og ”Producer-Archive Interface Methodology Abstract Standard” (”PAIMAS” ? ) så vi bliver bekræftet i at vi har tænkt på det hele.

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Idéer 5

Overveje at indgå i et arkivsamarbejde:

• Fælles søgemidler (på tværs af arkiver)

• Fælles ”Archival Storage” (bevaringsdel) – fælles digitalt bevaringscenter

• Fælles afleveringsformat og/eller udleveringsformat