interpretation of the oais model derek sergeant

Interpretation of the OAIS ModelInterpretation of the OAIS Model

Derek SergeantDerek Sergeant

http://www.leeds.ac.uk/camileon/

Overview of the OAIS ModelOverview of the OAIS Model

In order to become familiar with the In order to become familiar with the OAIS Reference ModelOAIS Reference Model

When Cedars staff first encountered the When Cedars staff first encountered the model it took them several months to model it took them several months to start grasping itstart grasping it

Re-iterate some of the things already Re-iterate some of the things already saidsaid


Specific vocabulary for Digital Specific vocabulary for Digital Preservation practionersPreservation practioners

Specific advice on how to sub-divide a Specific advice on how to sub-divide a complex taskcomplex task

Provides logic and structure to allow the Provides logic and structure to allow the digital holdings to be visualised and digital holdings to be visualised and processedprocessed


Much of the OAIS reference model does Much of the OAIS reference model does not need to be understood by the not need to be understood by the majority of people working in digital majority of people working in digital preservationpreservation

Some detail is only necessary to Some detail is only necessary to implement a solution (the low - level implement a solution (the low - level understanding)understanding)

Key concepts of the OAIS ModelKey concepts of the OAIS Model

OAISProducer Consumer

Management


The Producer creates and delivers the The Producer creates and delivers the digital objects which go into the OAISdigital objects which go into the OAIS

The Consumer asks for and receives The Consumer asks for and receives digital objects from the OAISdigital objects from the OAIS

The Management deals with high level The Management deals with high level OAIS policy and monitors the OAISOAIS policy and monitors the OAIS


The OAIS receives the digital objects The OAIS receives the digital objects from the producer, archives them, and from the producer, archives them, and supplies them to the consumer.supplies them to the consumer.


OAISProducer ConsumerSIPs

Management

AIPsDIPs


There are three basic types of There are three basic types of Information PackageInformation Package

The Producer and the OAIS The Producer and the OAIS communicate with Submission IPscommunicate with Submission IPs

The OAIS and the Consumer The OAIS and the Consumer communicate with Dissemination IPscommunicate with Dissemination IPs

The OAIS preserves Archive IPsThe OAIS preserves Archive IPs


SIPs AIPs DIPs

ContentInformation

PDI


Archival Information Packages contain Archival Information Packages contain both Content Information and both Content Information and Preservation Description InformationPreservation Description Information

Content Information is the digital object Content Information is the digital object that you need to preservethat you need to preserve

PDI is description and information to PDI is description and information to explain what the Content actually isexplain what the Content actually is


PDIAIP

ContentInformation

ContentData

ObjectRI


The Content Information part of an AIP The Content Information part of an AIP contains (very tightly coupled) the actual contains (very tightly coupled) the actual data object and the Representation data object and the Representation Information that makes the object Information that makes the object meaningfulmeaningful

Intellectual Content(genuine information)


ContentData

ObjectRI+ =


Long TermLong Term (The Representation Information needs (The Representation Information needs

to keep the Content Data to keep the Content Data understandable in the Long Term)understandable in the Long Term)

The knowledge base of the designated The knowledge base of the designated community (and the archive) needs to community (and the archive) needs to be monitored in the Long Termbe monitored in the Long Term


Producer Consumer

Management

Preservation Planning

Administration

Data Management

Archival Storage

AccessIngest


Ingest gets digital objects from the Ingest gets digital objects from the Producer into the OAISProducer into the OAIS

Access passes digital objects to the Access passes digital objects to the ConsumerConsumer

Data Management keeps track of the Data Management keeps track of the OAIS holdingsOAIS holdings

Archival Storage preserves AIPs in the Archival Storage preserves AIPs in the Long TermLong Term

The ScenarioThe Scenario

The Library that I work for has realised The Library that I work for has realised that over the past five years we are that over the past five years we are getting an increasing number of items getting an increasing number of items that are digitalthat are digital

At the last University Senate meeting At the last University Senate meeting the Pro-Vice Chancellor for Information the Pro-Vice Chancellor for Information Technology declared that we would Technology declared that we would keep these and make them availablekeep these and make them available


In order to do this it was realised that In order to do this it was realised that we need to develop a computer system we need to develop a computer system capable of storing these electronic capable of storing these electronic objects in a convenient form (to us)objects in a convenient form (to us)

Making them available should be just a Making them available should be just a case of duplicating the storage copy case of duplicating the storage copy and allowing a library user to download and allowing a library user to download the objectthe object


At the moment the digital objects that At the moment the digital objects that we have consist of we have consist of • CD Rom supplements that arrive with a CD Rom supplements that arrive with a

conventional bookconventional book• Electronic thesis from Postgrad ComputingElectronic thesis from Postgrad Computing• e-journal subscriptionse-journal subscriptions


Upon investigation, we found a Upon investigation, we found a Reference Model that describes exactly Reference Model that describes exactly what we need to do in order to preserve what we need to do in order to preserve and make available all of our digital and make available all of our digital objectsobjects

The OAIS Reference ModelThe OAIS Reference Model

Interpreting the OAIS ModelInterpreting the OAIS Model

Given that we have established a need Given that we have established a need to preserve the digital objects from our to preserve the digital objects from our library, and that we shall be archiving library, and that we shall be archiving them ourselves - in a newly formed them ourselves - in a newly formed library centre for preservation of library centre for preservation of electronic holdingselectronic holdings

We revisit the basic OAIS diagramWe revisit the basic OAIS diagram

Basic OAIS RelationshipsBasic OAIS Relationships

OAISProducer Consumer

Management


Identifying the Producers:Identifying the Producers: due to the number of types and sources due to the number of types and sources

of digital objects there are manyof digital objects there are many• e-journal publisherse-journal publishers• CD Rom book supplement publishersCD Rom book supplement publishers• Other Departments (e-thesis)Other Departments (e-thesis)

Are there emerging trends - new Are there emerging trends - new Producers in the futureProducers in the future


Identifying the Consumers:Identifying the Consumers: We inherit the same Consumers as the We inherit the same Consumers as the

librarylibrary• University studentsUniversity students• University staff/researchersUniversity staff/researchers

Are there going to be new Consumer Are there going to be new Consumer groups in the future?groups in the future?


Identifying the Management:Identifying the Management: Looking at the OAIS Model, we determine the Looking at the OAIS Model, we determine the

roles of Management:roles of Management:• Long term equipment planningLong term equipment planning• Review of OAIS performanceReview of OAIS performance• Ratify pricing policyRatify pricing policy• Relationship developmentRelationship development

– Producer OAIS ConsumerProducer OAIS Consumer

• Promote OAIS uptakePromote OAIS uptake– (within spheres of funding)(within spheres of funding)


Some of the roles of Management are very Some of the roles of Management are very close to the current roles of the library close to the current roles of the library managementmanagement

There are no existing people that already There are no existing people that already perform the other rolesperform the other roles

We will form a new Management group with We will form a new Management group with some existing library management and some existing library management and other senior university strategy managersother senior university strategy managers


Identify the OAIS:Identify the OAIS: Since we are intending to preserve our Since we are intending to preserve our

digital objects ourselves, we provide the digital objects ourselves, we provide the role of the OAISrole of the OAIS

Both the Archival store and the Both the Archival store and the administrationadministration


Identify the archive holdings:Identify the archive holdings:• Both present holdings and future holdingsBoth present holdings and future holdings

Present:Present:• e-thesise-thesis• CD Rom book supplementsCD Rom book supplements• (2 e-journal subscriptions)(2 e-journal subscriptions)

Future:Future:• more internal publicationsmore internal publications• more e-journalsmore e-journals

Structural Components of an AIPStructural Components of an AIP

PreservationDescriptionInformation

AIP

ContentData

Object

RepresentationInformation

Content Information


We do not have all of the components We do not have all of the components that are needed for an AIPthat are needed for an AIP

In the beginning, we have the Content In the beginning, we have the Content Data Object for everythingData Object for everything

For our e-thesis objects we also have a For our e-thesis objects we also have a small amount of PDIsmall amount of PDI

Lesson from the Cedars projectLesson from the Cedars project

Determine the Significant Properties for Determine the Significant Properties for the digital objectsthe digital objects

This should be done as early as This should be done as early as possiblepossible

Significant Properties are those Significant Properties are those attributes of an object that constitute the attributes of an object that constitute the complete (for the intended Consumer) complete (for the intended Consumer) intellectual content of that objectintellectual content of that object

Lesson from the Cedars projectLesson from the Cedars project

I.e. Significant Properties for an e-thesisI.e. Significant Properties for an e-thesis The complete text, including divisions into The complete text, including divisions into

chapters and sectionschapters and sections The layout and style - particular fonts and The layout and style - particular fonts and

spacing are essentialspacing are essential DiagramsDiagrams (perhaps web adverts are not Significant (perhaps web adverts are not Significant

for our e-journals)for our e-journals)


We have now established who we are We have now established who we are working withworking with

We have also established what data We have also established what data objects there areobjects there are

We have moved into OAIS vocabularyWe have moved into OAIS vocabulary Examples of old vocabularyExamples of old vocabulary

• Publishers, ReadersPublishers, Readers• Electronic recordsElectronic records

Functional Entities DiagramFunctional Entities Diagram

Producer Consumer

Management

Preservation Planning

Administration

Data Management

Archival Storage

AccessIngest


IngestIngest Establish agreements with ProducersEstablish agreements with Producers

• Record assumptions about Producer and Record assumptions about Producer and our (the OAIS) knowledge baseour (the OAIS) knowledge base

Take the digital data (SIPs)Take the digital data (SIPs) Process the SIPs into AIPsProcess the SIPs into AIPs

• Record any current software dependencies Record any current software dependencies to use the Content Data Objectto use the Content Data Object


Archival StorageArchival Storage Put the AIPs into Archival Storage from Put the AIPs into Archival Storage from

IngestIngest• Update the Data Management database to keep Update the Data Management database to keep

track of the OAIS holdingstrack of the OAIS holdings NB: The Archival Storage system that we NB: The Archival Storage system that we

procure will be capable of storing and procure will be capable of storing and retrieving an AIP without lossretrieving an AIP without loss• Storage, maintenance, retieval of AIPsStorage, maintenance, retieval of AIPs


Data ManagementData Management As well as keeping track of the AIPs As well as keeping track of the AIPs

currently in Archival Storage this entity currently in Archival Storage this entity produces Discovery Informationproduces Discovery Information

These can be passed to the Consumer These can be passed to the Consumer to allow them to choose suitable AIPs to allow them to choose suitable AIPs for viewingfor viewing


AccessAccess This provides support for the This provides support for the

ConsumersConsumers It delivers DIPs (in an appropriate form It delivers DIPs (in an appropriate form

for the particular Consumer)for the particular Consumer)


AdministrationAdministration Overall operational control of the OAISOverall operational control of the OAIS Records and makes submission Records and makes submission

agreements (with Producers)agreements (with Producers) Records and implements archiving Records and implements archiving

standards and policiesstandards and policies


Preservation PlanningPreservation Planning Monitors the environment of the OAISMonitors the environment of the OAIS Ensures that AIPs remain accessibleEnsures that AIPs remain accessible

• I.e. remain understandable to current I.e. remain understandable to current ConsumersConsumers

Develops templates for SIPs and DIPs Develops templates for SIPs and DIPs and other assistance for working with and other assistance for working with Producers and ConsumersProducers and Consumers

Responsibilities of an OAISResponsibilities of an OAIS

Negotiate and accept information from Negotiate and accept information from ProducersProducers

Determine which community should Determine which community should become the Designated Communitybecome the Designated Community

Ensure that Information Packages are Ensure that Information Packages are independently understandableindependently understandable

Ensure IPs are preservedEnsure IPs are preserved Make preserved IPs availableMake preserved IPs available

Organisational viewsOrganisational views

Establishing your Designated Establishing your Designated CommunityCommunity

The people who you service by The people who you service by preserving information for thempreserving information for them

Determining the knowledge base of the Determining the knowledge base of the Designated Community and monitoring Designated Community and monitoring changes to this knowledge basechanges to this knowledge base


The Perspective of PreservationThe Perspective of Preservation Long TermLong Term To do a preservation job which takes To do a preservation job which takes

into accountinto account• Changing technologyChanging technology• Changing user communityChanging user community


Deciding whether Digital Objects need Deciding whether Digital Objects need to be transformed (migrated)to be transformed (migrated)

If they do, ensuring that nothing If they do, ensuring that nothing significant to future Consumers is lostsignificant to future Consumers is lost

Are there alternatives to transformingAre there alternatives to transforming• Source code for original softwareSource code for original software• EmulationEmulation


Archive InteroperabilityArchive Interoperability The drivers for interoperability come The drivers for interoperability come

from:from:• The ConsumersThe Consumers• The ProducersThe Producers• The ManagementThe Management


Four basic models for interoperating in Four basic models for interoperating in the OAIS Reference Modelthe OAIS Reference Model

Independent - no interoperatingIndependent - no interoperating Co-operating - common producers, Co-operating - common producers,

common dissemination standardscommon dissemination standards Federated - the most interoperatingFederated - the most interoperating Shared Resource - reduce costs by Shared Resource - reduce costs by

sharing equipmentsharing equipment


Federated archivesFederated archives Central site?Central site? Distributed Finding AidsDistributed Finding Aids Distributed Access AidsDistributed Access Aids Issues:Issues:

• Unique AIP Names - hierarchical nameschemeUnique AIP Names - hierarchical namescheme• Duplicate AIPsDuplicate AIPs

Management - level of autonomyManagement - level of autonomy

Summary and QuestionsSummary and Questions

Federated archives : CedarsFederated archives : Cedars

Site C

Site B

Site A

How Can a Digital Resource be How Can a Digital Resource be prepared for good/lasting prepared for good/lasting preservation?preservation?

Give it a unique nameGive it a unique name

MetadataMetadata

Significant PropertiesSignificant Properties


StructureInformation

SemanticInformation

adds meaning

OAIS fig 4-10OAIS fig 4-10

OAIS Representation InformationOAIS Representation Information

Cedars Representation NetCedars Representation Net

RAE

RAEUAF

Transformer

FormatDescription Software Platform

Input format

Output format


A I P

Primary Digital Object PDI

RAE

RAE

Gödel’s TheoremGödel’s Theorem Some representations (e.g. plain ASCII Some representations (e.g. plain ASCII

text, MS-WORD, HTML) are defined text, MS-WORD, HTML) are defined outside the systemoutside the system

All references to such a format are via the All references to such a format are via the same CRIDsame CRID

The ends of representation nets must be The ends of representation nets must be managed, to look out for obsolescencemanaged, to look out for obsolescence

replace CRID destination with converter replace CRID destination with converter facilityfacility

Evolution of the Representation NetEvolution of the Representation Net

RAE

RAEUAF

Transformer


Input format

Output format


A I P


RAE

RAE

RAE

RAEUAF

Transformer


Input format

Output format


A I P


RAE

RAE


Platform

RAE

RAE

RAEUAF

Transformer


Input format

Output format


A I P


RAE

RAE


RAE

Platform

RAE

Obsolete data formatsObsolete data formats

Keep the original byte-streamsKeep the original byte-streams Representation info leads to sofware Representation info leads to sofware

capable of rendering the informationcapable of rendering the information Archive management must lookout for Archive management must lookout for

dependence on rendering software dependence on rendering software that is about to become obsolete.that is about to become obsolete.• Can use software preservation Can use software preservation

techniques to preserve rendering techniques to preserve rendering sofwaresofware

Emulation of YesteryearEmulation of Yesteryear

Today’s desktop machine far exceeds Today’s desktop machine far exceeds the mainframe of the 1970s or even 80sthe mainframe of the 1970s or even 80s

George3 (1970s UK system)George3 (1970s UK system)• Emulate the George3 executiveEmulate the George3 executive

– i.e. order code + system callsi.e. order code + system calls

Constructing RI for obsolete materials Constructing RI for obsolete materials proves a valuable test-bed for the modelproves a valuable test-bed for the model

Vital conceptsVital concepts CRIDS - give everything a unique nameCRIDS - give everything a unique name A byte-stream can be stored for everA byte-stream can be stored for ever

• Complex data streams must be mapped into Complex data streams must be mapped into byte-streams, and mapped back again for usebyte-streams, and mapped back again for use

Representation Information preserves Representation Information preserves access to intellectual contentaccess to intellectual content• makes emulation possiblemakes emulation possible

Gödel Ends are monitored for Gödel Ends are monitored for obsolescenceobsolescence

The The ArchivalArchival InformationInformation PackagePackage

PreservationDescriptionInformation


Primary DigitalObject

Packed together into one AIP bytestream using ASN.1Packed together into one AIP bytestream using ASN.1

Property listProperty listXMLXML Packed into bytestreamPacked into bytestream

• Links to Representation NetworkLinks to Representation Network

• Links for other purposesLinks for other purposes

Choices at Creation of AIPChoices at Creation of AIP

Geared towards easy/low maintenanceGeared towards easy/low maintenance Identify which parts of PDI are fixed/staticIdentify which parts of PDI are fixed/static Use current best archival method to map Use current best archival method to map

the digital resource into a bytestream the digital resource into a bytestream (PDO then remains static)(PDO then remains static)

For common (esp. changing) metadata For common (esp. changing) metadata use indirectionuse indirection

Representation InformationRepresentation Information

Technical MetadataTechnical Metadata

Evolving TechnologyEvolving Technology

Representation NetworksRepresentation Networks

Format DescriptionsFormat Descriptions

Rendering InstructionsRendering Instructions

Controversy ThreeControversy Three

A Digital Message can be Preserved A Digital Message can be Preserved IndefinitelyIndefinitely

This is media - lessThis is media - less

The Preserved resource hops media The Preserved resource hops media long before temporal effects loose itlong before temporal effects loose it

Digitisation and Access have a placeDigitisation and Access have a place

interpretation of the oais model derek sergeant

Documents

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dissemination ipsthe

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oais modelin order