There are many terms which are used in this reference model and which need to have well- defined meanings. These terms are defined in this subsection. When first used in the text, they are shown in bold and are capitalized. Subsequent use employs capitalization only.
As this reference model is applicable to all disciplines and organizations that do, or expect to, preserve and provide information in digital form, these terms cannot match all of those familiar to any particular discipline (e.g., traditional Archives, digital libraries, science data centers). Rather, the approach taken is to use terms that are not already overloaded with meaning so as to reduce conveying unintended meanings. Therefore it is expected that all disciplines and organizations will find that they need to map some of their more familiar terms to those of the OAIS Reference Model. This should not be difficult and is viewed as a contribution, rather than a deterrent, to the success of the reference model. For example, archival science focuses on preservation of the ‘record’. This term is not used in the OAIS Reference Model, but one mapping might approximately equate it with ‘Content Information within an Archival Information Package’ (see definitions below, as well as 2.2 and 4.2 for context). A few such mappings are provided in annex B.
Access Functional Entity: The OAIS functional entity that contains the services and functions which make the archival information holdings and related services visible to Consumers.
Access Rights Information: The information that identifies the access restrictions pertaining to the Content Information, including the legal framework, licensing terms, and access control. It contains the access and distribution conditions stated within the Submission Agreement, related to both preservation (by the OAIS) and final usage (by the Consumer). It also includes the specifications for the application of rights enforcement measures.
'Access Aid: A software program or document that allows Consumers to locate, analyze, order or retrieve information from an OAIS.
Access Collection: A collection of AIPs that is defined by a Collection Description but for which there is no Packaging Information for the collection in Archival Storage.
Access Software: A type of software that presents part of or all of the information content of an Information Object in forms understandable to humans or systems.
Adhoc Order: A request that is generated by a Consumer for information the OAIS has indicated is currently available.
Administration Functional Entity: The OAIS functional entity that contains the services and functions needed to control the operation of the other OAIS functional entities on a day- to-day basis.
AIP Edition: An AIP whose Content Information or Preservation Description Information has been upgraded or improved with the intent not to preserve information, but to increase or improve it. An AIP edition is not considered to be the result of a Migration.
AIP Version: An AIP whose Content Information or Preservation Description Information has undergone a Transformation on a source AIP and is a candidate to replace the source AIP. An AIP version is considered to be the result of a Digital Migration.
Archival Information Collection (AIC): An Archival Information Package whose Content Information is an aggregation of other Archival Information Packages.
Archival Information Package (AIP): An Information Package, consisting of the Content Information and the associated Preservation Description Information (PDI), which is preserved within an OAIS.
Archival Information Unit (AIU): An Archival Information Package where the Archive chooses not to break down the Content Information into other Archival Information Packages. An AIU can consist of multiple digital objects (e.g., multiple files).
Archival Storage Functional Entity: The OAIS functional entity that contains the services and functions used for the storage and retrieval of Archival Information Packages.
Archive: An organization that intends to preserve information for access and use by a Designated Community.
Associated Description: The information describing the content of an Information Package from the point of view of a particular Access Aid.
Authenticity: The degree to which a person (or system) regards an object as what it is purported to be. Authenticity is judged on the basis of evidence.
Collection Description: A type of Package Description that is specialized to provide information about an Archival Information Collection for use by Access Aids.
Common Services: The supporting services such as inter-process communication, name services, temporary storage allocation, exception handling, security, and directory services necessary to support the OAIS.
Consumer: The role played by those persons, or client systems, who interact with OAIS services to find preserved information of interest and to access that information in detail. This can include other OAISes, as well as internal OAIS persons or systems.
Content Data Object: The Data Object, that together with associated Representation Information, comprises the Content Information.
Content Information: A set of information that is the original target of preservation or that includes part or all of that information. It is an Information Object composed of its Content Data Object and its Representation Information.
Context Information: The information that documents the relationships of the Content Information to its environment. This includes why the Content Information was created and how it relates to other Content Information objects.
Co-operating Archives: Those Archives that have Designated Communities with related interests. They may order and ingest data from each other. At a minimum, Co-operating Archives must agree to support at least one common Submission Information Package (SIP) and Dissemination Information Package (DIP) for inter-Archive requests.
Data: A reinterpretable representation of information in a formalized manner suitable for communication, interpretation, or processing. Examples of data include a sequence of bits, a table of numbers, the characters on a page, the recording of sounds made by a person speaking, or a moon rock specimen.
Data Dictionary: A formal repository of terms used to describe data.
Data Dissemination Session: A delivery of media or a single telecommunications session that provides Data to a Consumer. The Data Dissemination Session format/contents is based on a data model negotiated between the OAIS and the Consumer in the request agreement. This data model identifies the logical constructs used by the OAIS and how they are represented on each media delivery or in the telecommunication session.
Data Management Functional Entity: The OAIS functional entity that contains the services and functions for populating, maintaining, and accessing a wide variety of information. Some examples of this information are catalogs and inventories on what may be retrieved from Archival Storage, processing algorithms that may be run on retrieved data, Consumer access statistics, Consumer billing, Event Based Orders, security controls, and OAIS schedules, policies, and procedures.
Data Management Data: The data created and stored in Data Management persistent storage that refer to operation of an Archive. Some examples of this data are accounting data for Consumer billing and authorization, policy data, Event Based Order (subscription) data for repeating requests, preservation process history data, and statistical data for generating reports to Archive management.
Data Object: Either a Physical Object or a Digital Object.
Data Submission Session: A delivery of media or a single telecommunications session that provides Data to an OAIS. The Data Submission Session format/contents is based on a data model negotiated between the OAIS and the Producer in the Submission Agreement. This data model identifies the logical constructs used by the Producer and how they are represented on each media delivery or in the telecommunication session.
Derived AIP: An AIP generated by extracting or aggregating information from one or more source AIPs.
Descriptive Information: The set of information, consisting primarily of Package Descriptions, which is provided to Data Management to support the finding, ordering, and retrieving of OAIS information holdings by Consumers.
Designated Community: An identified group of potential Consumers who should be able to understand a particular set of information. The Designated Community may be composed of multiple user communities. A Designated Community is defined by the Archive and this definition may change over time.
Digital Migration: The transfer of digital information, while intending to preserve it, within the OAIS. It is distinguished from transfers in general by three attributes:
– a focus on the preservation of the full information content that needs preservation;
– a perspective that the new archival implementation of the information is a replacement for the old; and
– an understanding that full control and responsibility over all aspects of the transfer resides with the OAIS.
Digital Object: An object composed of a set of bit sequences.
Dissemination Information Package (DIP): An Information Package, derived from one or more AIPs, and sent by Archives to the Consumer in response to a request to the OAIS.
Event Based Order: A request that is generated by a Consumer for information that is to be delivered periodically on the basis of some event or events.
Federated Archives: A group of Archives that has agreed to provide access to their holdings via one or more common finding aids.
Finding Aid: A type of Access Aid that allows a user to search for and identify Archival Information Packages of interest.
Fixity Information: The information which documents the mechanisms that ensure that the Content Information object has not been altered in an undocumented manner. An example is a Cyclical Redundancy Check (CRC) code for a file.
Global Community: An extended Consumer community, in the context of Federated Archives, that accesses the holdings of several Archives via one or more common Finding Aids.
Independently Understandable: A characteristic of information that is sufficiently complete to allow it to be interpreted, understood and used by the Designated Community without having to resort to special resources not widely available, including named individuals.
Information: Any type of knowledge that can be exchanged. In an exchange, it is represented by data. An example is a string of bits (the data) accompanied by a description of how to interpret the string of bits as numbers representing temperature observations measured in degrees Celsius (the Representation Information).
Information Object: A Data Object together with its Representation Information.
Information Package: A logical container composed of optional Content Information and optional associated Preservation Description Information. Associated with this Information Package is Packaging Information used to delimit and identify the Content Information and Package Description information used to facilitate searches for the Content Information.
Information Property: That part of the Content Information as described by the Information Property Description. The detailed expression, or value, of that part of the information content is conveyed by the appropriate parts of the Content Data Object and its Representation Information.
Information Property Description: The description of the Information Property. It is a description of a part of the information content of a Content Information object that is highlighted for a particular purpose.
Ingest Functional Entity: The OAIS functional entity that contains the services and functions that accept Submission Information Packages from Producers, prepares Archival Information Packages for storage, and ensures that Archival Information Packages and their supporting Descriptive Information become established within the OAIS.
Knowledge Base: A set of information, incorporated by a person or system, that allows that person or system to understand received information.
Local Community: The community which would be served by the Archive outside of the context of Federated Archives.
Long Term: A period of time long enough for there to be concern about the impacts of changing technologies, including support for new media and data formats, and of a changing Designated Community, on the information being held in an OAIS. This period extends into the indefinite future. Long Term Preservation: The act of maintaining information, Independently Understandable by a Designated Community, and with evidence supporting its Authenticity, over the Long Term.
Management: The role played by those who set overall OAIS policy as one component in a broader policy domain, for example as part of a larger organization.
Member Description: An Associated Description that describes a member of a collection.
Metadata: Data about other data.
Non-Reversible Transformation: A Transformation which cannot be guaranteed to be a Reversible Transformation.
Open Archival Information System (OAIS): An Archive, consisting of an organization, which may be part of a larger organization, of people and systems, that has accepted the responsibility to preserve information and make it available for a Designated Community. It meets a set of responsibilities, as defined in section 4, that allows an OAIS Archive to be distinguished from other uses of the term ‘Archive’. The term ‘Open’ in OAIS is used to imply that this Recommendation and future related Recommendations and standards are developed in open forums, and it does not imply that access to the Archive is unrestricted.
Order Agreement: An agreement between the Archive and the Consumer in which the physical details of the delivery, such as media type and format of Data, are specified.
Ordering Aid: An application that assists the Consumer in discovering the cost of, and in ordering, AIPs of interest.
Other Representation Information: Representation Information which cannot easily be classified as Semantic or Structural. For example software, algorithms, encryption, written instructions and many other things may be needed to understand the Content Data Object, all of which therefore would be, by definition, Representation Information, yet would not obviously be either Structure or Semantics. Information defining how the Structure and the Semantic Information relate to each other, or software needed to process a database file would also be regarded as Other Representation Information.
Overview Description: A specialization of the Collection Description that describes the collection as a whole.
Package Description: The information intended for use by Access Aids.
Packaging Information: The information that is used to bind and identify the components of an Information Package. For example, it may be the ISO 9660 volume and directory information used on a CD-ROM to provide the content of several files containing Content Information and Preservation Description Information.
Physical Object: An object (such as a moon rock, bio-specimen, microscope slide) with physically observable properties that represent information that is considered suitable for being adequately documented for preservation, distribution, and independent usage.
Preservation Description Information (PDI): The information which is necessary for adequate preservation of the Content Information and which can be categorized as Provenance, Reference, Fixity, Context, and Access Rights Information.
Preservation Planning Functional Entity: The OAIS functional entity which provides the services and functions for monitoring the environment of the OAIS and which provides recommendations and preservation plans to ensure that the information stored in the OAIS remains accessible to, and understandable by, and sufficiently usable by, the Designated Community over the Long Term, even if the original computing environment becomes obsolete.
Producer: The role played by those persons or client systems that provide the information to be preserved. This can include other OAISes or internal OAIS persons or systems.
Provenance Information: The information that documents the history of the Content Information. This information tells the origin or source of the Content Information, any changes that may have taken place since it was originated, and who has had custody of it since it was originated. The Archive is responsible for creating and preserving Provenance Information from the point of Ingest; however, earlier Provenance Information should be provided by the Producer. Provenance Information adds to the evidence to support Authenticity.
Reference Information: The information that is used as an identifier for the Content Information. It also includes identifiers that allow outside systems to refer unambiguously to a particular Content Information. An example of Reference Information is an ISBN.
Reference Model: A framework for understanding significant relationships among the entities of some environment, and for the development of consistent standards or specifications supporting that environment. A reference model is based on a small number of unifying concepts and may be used as a basis for education and explaining standards to a non-specialist.
Refreshment: A Digital Migration where the effect is to replace a media instance with a copy that is sufficiently exact that all Archival Storage hardware and software continues to run as before.
Repackaging: A Digital Migration in which there is an alteration in the Packaging Information of the AIP.
Replication: A Digital Migration where there is no change to the Packaging Information, the Content Information, and the PDI. The bits used to represent these Information Objects are preserved in the transfer to the same or new media instance.
Representation Information: The information that maps a Data Object into more meaningful concepts. An example of Representation Information for a bit sequence which is a FITS file might consist of the FITS standard which defines the format plus a dictionary which defines the meaning in the file of keywords which are not part of the standard.
Another example is JPEG software which is used to render a JPEG file; rendering the JPEG file as bits is not very meaningful to humans but the software, which embodies an understanding of the JPEG standard, maps the bits into pixels which can then be rendered as an image for human viewing.
Representation Network: The set of Representation Information that fully describes the meaning of a Data Object. Representation Information in digital forms needs additional Representation Information so its digital forms can be understood over the Long Term.
Representation Rendering Software: A type of software that displays Representation Information of an Information Object in forms understandable to humans.
Retrieval Aid: An application that allows authorized users to retrieve the Content Information and PDI described by the Package Description.
Reversible Transformation: A Transformation in which the new representation defines a set (or a subset) of resulting entities that are equivalent to the resulting entities defined by the original representation. This means that there is a one-to-one mapping back to the original representation and its set of base entities.
Search Session: A session initiated by the Consumer with the Archive during which the Consumer will use the Archive Finding Aids to identify and investigate potential holdings of interest.
Semantic Information: The Representation Information that further describes the meaning beyond that provided by the Structure Information.
Structure Information: The Representation Information that imparts meaning about how other information is organized. For example, it maps bit streams to common computer types such as characters, numbers, and pixels and aggregations of those types such as character strings and arrays.
Submission Agreement: The agreement reached between an OAIS and the Producer that specifies a data model, and any other arrangements needed, for the Data Submission Session. This data model identifies format/contents and the logical constructs used by the Producer and how they are represented on each media delivery or in a telecommunication session.
Submission Information Package (SIP): An Information Package that is delivered by the Producer to the OAIS for use in the construction or update of one or more AIPs and/or the associated Descriptive Information.
Succession Plan: The plan of how and when the management, ownership and/or control of the OAIS holdings will be transferred to a subsequent OAIS in order to ensure the continued effective preservation of those holdings.
Transformation: A Digital Migration in which there is an alteration to the Content Information or PDI of an Archival Information Package. For example, changing ASCII codes to UNICODE in a text document being preserved is a Transformation.
Transformational Information Property: An Information Property the preservation of the value of which is regarded as being necessary but not sufficient to verify that any Non- Reversible Transformation has adequately preserved information content. This could be important as contributing to evidence about Authenticity. Such an Information Property is dependent upon specific Representation Information, including Semantic Information, to denote how it is encoded and what it means. (The term ‘significant property’, which has various definitions in the literature, is sometimes used in a way that is consistent with its being a Transformational Information Property).
Unit Description: A type of Package Description that is specialized to provide information about an Archival Information Unit for use by Access Aids.
--Please retain original text above for reference. Propose amendments or additions below this line or respond using the Discussion tab above--
These wiki pages are licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. Attribute as "Community forum for digital preservation and curation standards http://wiki.dpconline.org/". The content on this wiki represents the opinions of the author and not the Digital Preservation Coalition. This wiki is not associated with ISO, the OAIS Standard or the CCSDS.