Definition
A set of characteristics describing a Data Object (such as the size of this object and the description of its content). Typically there will be multiple Data Objects conforming to the same Data Object Type.
Source: Consultative Committee on Space Data Systems. Producer-Archive Interface Specification. CCSDS 651.1-B-1.
Introduction
OAIS models information around the principle that "data interpreted using its representation information yields information." This principle enables libraries, archives, and museums to apply one conceptual data model to physical objects and digital objects.
Obtaining information from data. Consultative Committee on Space Data Systems. Open Archival Information System (OAIS) recommended practice, Figure 2-2. CCSDS 650.0-M-2.
This principle enables libraries, archives, and museums to apply one conceptual data model to physical objects and digital objects.
Characteristics
Data Object Types are described as part of a Transfer Object Type Descriptor. https://sanaregistry.org/r/daixml
<xsd:complexType name="dataObjectType"> <xsd:sequence> <xsd:element name="dataObjectTypeID" type="xsd:string"> <xsd:annotation> <xsd:documentation> Identifier of the Data Object Type. It shall be unique across the Producer-Archive Project. Uniqueness shall be checked by the Archive. This identifier can be used by a relationship element to refer to this Data Object Type. </xsd:documentation> </xsd:annotation> </xsd:element> <xsd:element name="dataObjectTypeDescription" type="xsd:string" minOccurs="0"> <xsd:annotation> <xsd:documentation> Explanatory text describing the meaning of this Data Object Type. </xsd:documentation> </xsd:annotation> </xsd:element> <xsd:element name="dataObjectTypeOccurrence" type="pais:occurrenceType"> <xsd:annotation> <xsd:documentation> Parent element supporting the number of instances (Data Objects) of this Data Object Type in each instance of its containing group. This may be expressed as one, or more, or as a range of values. This number may not be known at the time of descriptor creation and instantiation. In the case of a unique value, then minOccurrence = maxOccurrence = value. </xsd:documentation> </xsd:annotation> </xsd:element> <xsd:element name="dataObjectTypeFileOccurrence" type="pais:occurrenceType" minOccurs="0"> <xsd:annotation> <xsd:documentation> Parent element supporting the number of file instances in each Data Object Type instance. This may be expressed as one, or more, or as a range of values. This number may not be known at the time of descriptor creation and instantiation. In the case of a unique value, then minOccurrence = maxOccurrence = value. The absence of this element implies there shall be one file instance. </xsd:documentation> </xsd:annotation> </xsd:element> <xsd:element name="dataObjectTypeFormat" minOccurs="0"> <xsd:annotation> <xsd:documentation> Parent element supporting the identification of the format of this Data Object Type in the Transfer Object Group Type using a MIME type or a registration mechanism. </xsd:documentation> </xsd:annotation> <xsd:complexType> <xsd:sequence> <xsd:element name="mimeType" type="xsd:string" minOccurs="0"> <xsd:annotation> <xsd:documentation> MIME type for the Data Object Type (e.g., "application/octet-stream" MIME type as documented by the Internet Engineering Task Force (IETF)). </xsd:documentation> </xsd:annotation> </xsd:element> <xsd:element name="registrationInformation" minOccurs="0"> <xsd:annotation> <xsd:documentation> Parent element supporting information used to identify the format of this Data Object Type as registered with a specified registration authority. </xsd:documentation> </xsd:annotation> <xsd:complexType> <xsd:sequence> <xsd:element name="registrationAuthority" type="xsd:string" minOccurs="0"> <xsd:annotation> <xsd:documentation> Identifier of the organization or system that has registered and holds the format description (e.g.,IETF, CCSDS Control Authority(CA)). </xsd:documentation> </xsd:annotation> </xsd:element> <xsd:element name="registeredID" type="xsd:string" minOccurs="0"> <xsd:annotation> <xsd:documentation> Identifier of the format description within the context of the registration authority (e.g., NSSD0145 under CCSDS CA). </xsd:documentation> </xsd:annotation> </xsd:element> </xsd:sequence> </xsd:complexType> </xsd:element> </xsd:sequence> </xsd:complexType> </xsd:element> <xsd:element name="dataObjectTypeEncoded" type="pais:encodingType" minOccurs="0" maxOccurs="unbounded"> <xsd:annotation> <xsd:documentation> Characterization of how a Data Object has been encoded. May be used to describe possible nested encodings, for example a Data Object encoded in a zip file and then encoded in a binhex file. </xsd:documentation> </xsd:annotation> </xsd:element> <xsd:element name="dataObjectTypeAssociation" type="pais:associationType" minOccurs="0" maxOccurs="unbounded"> <xsd:annotation> <xsd:documentation> Parent element supporting the description of a relationship from this Data Object Type to the object type or collection having the identifier given by the targetID element (targeted object types include Data Object Type, Transfer Object Type, and Transfer Object Group Type). These are transversal links specifying the type of relation. </xsd:documentation> </xsd:annotation> </xsd:element> <xsd:element name="any" type="pais:extensionType" minOccurs="0"> <xsd:annotation> <xsd:documentation> Allows a conforming XML document to have any additional XML elements at this point in its structure. </xsd:documentation> </xsd:annotation> </xsd:element> </xsd:sequence> </xsd:complexType>
Types of Data Objects
Data Objects can be organized into two broad classes: physical and digital. Physical objects can include analog or digital information.
Physical
Analog
Motion picture film
Phonograph records
Photographic material
Magnetic tape
Magnetic audio tape
Magnetic video tape
Paper
Digital
Digital audio tape
Digital videocassette
Optical disc
Floppy disk
Hard drive
Digital
Email
Presentations
Rastor images
Word processing
Relationship to Descriptor Models
Section 3.2.2.5 of the Producer-Archive Interface Specification (PAIS) models Transfer Object Group Types. Each type of Transfer Object Group can have one or more types of data objects.