Definition

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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 (PAIS). Recommendation for Space Data System Standards, CCSDS 651.1-B-1. Blue Book. Issue 1. Washington, D.C.: CCSDS, February 2014. [Equivalent to ISO 20104:2015]

Introduction

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Submission Information Packages (SIPs) include one or more Transfer Objects. A Transfer Object is a set of one or more Transfer Object Groups containing at least one Data Object that are to be transferred to the Archive.

PAIS 2.2 explains that:

One of the objectives of the Formal Definition Phase is to define the Data Objects, where hereafter a Data Object is understood to be one or more data files, to be transferred as possibly more complex data structures called Transfer Objects. Each Transfer Object is an instance of a particular Transfer Object Type. Each Transfer Object Type is described in detail by a Transfer Object Type Descriptor. A Transfer Object Type Descriptor consists of a set of mandatory, optional, and possibly user-defined attributes, and is generated for each type of Transfer Object.

Open Archival Information System (OAIS)

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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.

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

Code Block <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

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Data Objects can be organized into two broad classes: physical and digital. Physical objects can include analog formats or digital storage devices.

• Physical

  • Analog

    • Motion picture film

    • Phonograph records

    • Photographic material

    • Magnetic tape

      • Magnetic audio tape

      • Magnetic video tape

    • Paper

  • Digital storage device

    • Digital audio tape

    • Digital videocassette

    • Optical disc

    • Floppy disk

    • Hard drive

• Digital

  • Email

  • Presentations

  • Rastor images

  • Word processing

Relationship to Descriptor Models

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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.

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