Interpretation of the OAIS Model Derek Sergeant http://www.leeds.ac.uk/camileon/ Overview of the OAIS Model In order to become familiar with the OAIS Reference Model When.
Download ReportTranscript Interpretation of the OAIS Model Derek Sergeant http://www.leeds.ac.uk/camileon/ Overview of the OAIS Model In order to become familiar with the OAIS Reference Model When.
Interpretation of the OAIS Model Derek Sergeant http://www.leeds.ac.uk/camileon/ Overview of the OAIS Model In order to become familiar with the OAIS Reference Model When Cedars staff first encountered the model it took them several months to start grasping it Re-iterate some of the things already said Overview of the OAIS Model Specific vocabulary for Digital Preservation practioners Specific advice on how to sub-divide a complex task Provides logic and structure to allow the digital holdings to be visualised and processed Overview of the OAIS Model Much of the OAIS reference model does not need to be understood by the majority of people working in digital preservation Some detail is only necessary to implement a solution (the low - level understanding) Key concepts of the OAIS Model Producer OAIS Management Consumer Key concepts of the OAIS Model The Producer creates and delivers the digital objects which go into the OAIS The Consumer asks for and receives digital objects from the OAIS The Management deals with high level OAIS policy and monitors the OAIS Key concepts of the OAIS Model The OAIS receives the digital objects from the producer, archives them, and supplies them to the consumer. Key concepts of the OAIS Model Producer OAIS SIPs Consumer DIPs AIPs Management Key concepts of the OAIS Model There are three basic types of Information Package The Producer and the OAIS communicate with Submission IPs The OAIS and the Consumer communicate with Dissemination IPs The OAIS preserves Archive IPs Key concepts of the OAIS Model SIPs AIPs Content PDI Information DIPs Key concepts of the OAIS Model Archival Information Packages contain both Content Information and Preservation Description Information Content Information is the digital object that you need to preserve PDI is description and information to explain what the Content actually is Key concepts of the OAIS Model Content Data Object AIP RI Content PDI Information Key concepts of the OAIS Model The Content Information part of an AIP contains (very tightly coupled) the actual data object and the Representation Information that makes the object meaningful Key concepts of the OAIS Model Content Data Object + RI Intellectual Content =(genuine information) Key concepts of the OAIS Model Long Term (The Representation Information needs to keep the Content Data understandable in the Long Term) The knowledge base of the designated community (and the archive) needs to be monitored in the Long Term Key concepts of the OAIS Model Preservation Planning Data Management Producer Ingest Access Archival Storage Administration Management Consumer Key concepts of the OAIS Model Ingest gets digital objects from the Producer into the OAIS Access passes digital objects to the Consumer Data Management keeps track of the OAIS holdings Archival Storage preserves AIPs in the Long Term The Scenario The Library that I work for has realised that over the past five years we are getting an increasing number of items that are digital At the last University Senate meeting the Pro-Vice Chancellor for Information Technology declared that we would keep these and make them available The Scenario In order to do this it was realised that we need to develop a computer system capable of storing these electronic objects in a convenient form (to us) Making them available should be just a case of duplicating the storage copy and allowing a library user to download the object The Scenario At the moment the digital objects that we have consist of • CD Rom supplements that arrive with a conventional book • Electronic thesis from Postgrad Computing • e-journal subscriptions The Scenario Upon investigation, we found a Reference Model that describes exactly what we need to do in order to preserve and make available all of our digital objects The OAIS Reference Model Interpreting the OAIS Model Given that we have established a need to preserve the digital objects from our library, and that we shall be archiving them ourselves - in a newly formed library centre for preservation of electronic holdings We revisit the basic OAIS diagram Basic OAIS Relationships Producer OAIS Management Consumer Interpreting the OAIS Model Identifying the Producers: due to the number of types and sources of digital objects there are many • e-journal publishers • CD Rom book supplement publishers • Other Departments (e-thesis) Are there emerging trends - new Producers in the future Interpreting the OAIS Model Identifying the Consumers: We inherit the same Consumers as the library • University students • University staff/researchers Are there going to be new Consumer groups in the future? Interpreting the OAIS Model Identifying the Management: Looking at the OAIS Model, we determine the roles of Management: • • • • Long term equipment planning Review of OAIS performance Ratify pricing policy Relationship development – Producer OAIS Consumer • Promote OAIS uptake – (within spheres of funding) Interpreting the OAIS Model Some of the roles of Management are very close to the current roles of the library management There are no existing people that already perform the other roles We will form a new Management group with some existing library management and other senior university strategy managers Interpreting the OAIS Model Identify the OAIS: Since we are intending to preserve our digital objects ourselves, we provide the role of the OAIS Both the Archival store and the administration Interpreting the OAIS Model Identify the archive holdings: • Both present holdings and future holdings Present: • e-thesis • CD Rom book supplements • (2 e-journal subscriptions) Future: • more internal publications • more e-journals Structural Components of an AIP Content Information AIP Content Data Object Representation Information Preservation Description Information Interpreting the OAIS Model We do not have all of the components that are needed for an AIP In the beginning, we have the Content Data Object for everything For our e-thesis objects we also have a small amount of PDI Lesson from the Cedars project Determine the Significant Properties for the digital objects This should be done as early as possible Significant Properties are those attributes of an object that constitute the complete (for the intended Consumer) intellectual content of that object Lesson from the Cedars project I.e. Significant Properties for an e-thesis The complete text, including divisions into chapters and sections The layout and style - particular fonts and spacing are essential Diagrams (perhaps web adverts are not Significant for our e-journals) Interpreting the OAIS Model We have now established who we are working with We have also established what data objects there are We have moved into OAIS vocabulary Examples of old vocabulary • Publishers, Readers • Electronic records Functional Entities Diagram Preservation Planning Data Management Producer Ingest Access Archival Storage Administration Management Consumer Interpreting the OAIS Model Ingest Establish agreements with Producers • Record assumptions about Producer and our (the OAIS) knowledge base Take the digital data (SIPs) Process the SIPs into AIPs • Record any current software dependencies to use the Content Data Object Interpreting the OAIS Model Archival Storage Put the AIPs into Archival Storage from Ingest • Update the Data Management database to keep track of the OAIS holdings NB: The Archival Storage system that we procure will be capable of storing and retrieving an AIP without loss • Storage, maintenance, retieval of AIPs Interpreting the OAIS Model Data Management As well as keeping track of the AIPs currently in Archival Storage this entity produces Discovery Information These can be passed to the Consumer to allow them to choose suitable AIPs for viewing Interpreting the OAIS Model Access This provides support for the Consumers It delivers DIPs (in an appropriate form for the particular Consumer) Interpreting the OAIS Model Administration Overall operational control of the OAIS Records and makes submission agreements (with Producers) Records and implements archiving standards and policies Interpreting the OAIS Model Preservation Planning Monitors the environment of the OAIS Ensures that AIPs remain accessible • I.e. remain understandable to current Consumers Develops templates for SIPs and DIPs and other assistance for working with Producers and Consumers Responsibilities of an OAIS Negotiate and accept information from Producers Determine which community should become the Designated Community Ensure that Information Packages are independently understandable Ensure IPs are preserved Make preserved IPs available Organisational views Establishing your Designated Community The people who you service by preserving information for them Determining the knowledge base of the Designated Community and monitoring changes to this knowledge base Organisational views The Perspective of Preservation Long Term To do a preservation job which takes into account • Changing technology • Changing user community Organisational views Deciding whether Digital Objects need to be transformed (migrated) If they do, ensuring that nothing significant to future Consumers is lost Are there alternatives to transforming • Source code for original software • Emulation Organisational views Archive Interoperability The drivers for interoperability come from: • The Consumers • The Producers • The Management Organisational views Four basic models for interoperating in the OAIS Reference Model Independent - no interoperating Co-operating - common producers, common dissemination standards Federated - the most interoperating Shared Resource - reduce costs by sharing equipment Organisational views Federated archives Central site? Distributed Finding Aids Distributed Access Aids Issues: • Unique AIP Names - hierarchical namescheme • Duplicate AIPs Management - level of autonomy Summary and Questions Federated archives : Cedars Site A Site C Site B How Can a Digital Resource be prepared for good/lasting preservation? Give it a unique name Metadata Significant Properties OAIS Representation Information Representation Information Structure Information adds meaning OAIS fig 4-10 Semantic Information Cedars Representation Net AIP PDI Representation Information Primary Digital Object RAE UAF RAE RAE Transformer Format Description RAE Software Input format Output format Platform Gödel’s Theorem Some representations (e.g. plain ASCII text, MS-WORD, HTML) are defined outside the system All references to such a format are via the same CRID The ends of representation nets must be managed, to look out for obsolescence replace CRID destination with converter facility Evolution of the Representation Net AIP PDI Representation Information Primary Digital Object RAE UAF RAE RAE Transformer Format Description RAE Software Input format Output format Platform Evolution of the Representation Net AIP PDI Representation Information Primary Digital Object RAE UAF RAE RAE Transformer Format Description RAE RAE Software Input format Output format Platform Platform Evolution of the Representation Net AIP PDI Representation Information Primary Digital Object RAE UAF RAE RAE Transformer Format Description RAE RAE Software RAE Input format Output format Platform Platform Obsolete data formats Keep the original byte-streams Representation info leads to sofware capable of rendering the information Archive management must lookout for dependence on rendering software that is about to become obsolete. • Can use software preservation techniques to preserve rendering sofware Emulation of Yesteryear Today’s desktop machine far exceeds the mainframe of the 1970s or even 80s George3 (1970s UK system) • Emulate the George3 executive – i.e. order code + system calls Constructing RI for obsolete materials proves a valuable test-bed for the model Vital concepts CRIDS - give everything a unique name A byte-stream can be stored for ever • Complex data streams must be mapped into byte-streams, and mapped back again for use Representation Information preserves access to intellectual content • makes emulation possible Gödel Ends are monitored for obsolescence The Archival Information Package Preservation Description Information XML Representation Information Primary Digital Object Property list Packed into bytestream Packed together into one AIP bytestream using ASN.1 • Links to Representation Network • Links for other purposes Choices at Creation of AIP Geared towards easy/low maintenance Identify which parts of PDI are fixed/static Use current best archival method to map the digital resource into a bytestream (PDO then remains static) For common (esp. changing) metadata use indirection Rendering Instructions Format Descriptions Representation Information Technical Metadata Evolving Technology Representation Networks Controversy Three A Digital Message can be Preserved Indefinitely This is media - less The Preserved resource hops media long before temporal effects loose it Digitisation and Access have a place