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PREservation Metadata: Implementation Strategies (PREMIS) is the de facto digital preservation metadata standard. Digital preservation metadata defines the information that is needed to ensure the long-term usability of digital objects to keep them accessible in some form in the future. Digital preservation metadata is particularly important for repositories, places where information objects are stored and managed for a long time. Simply storing digital objects on a data carrier is not enough to keep them usable. They need to be managed in a repository so that they are protected from accidental or intentional damage and so that a full computing environment can be created in which they can be accessed and understood when they are needed. Information objects have descriptive metadata, information about the object that could be used to discover, access and identify the digital object. This metadata is, however, not enough to preserve the digital objects in the long-term. For example, the digital object's file format can become obsolete and unusable by future software applications. This would require either transforming the older format to a newer one (migration), or reproducing the original experience with newer technology (emulation). Both strategies would require the additional information, such as technical metadata about the original files, information about the older hardware and software that they ran on, and information about actions that have transformed the digital object over time. All of these are types of preservation metadata. Preservation metadata therefore supports activities intended to ensure the long-term usability of a digital resource. In the early 2000s it became clear that a shared community metadata standard was needed to ensure long-term preservation of the ever-increasing digital resources. Experts from key memory institutions and repository developers joined together to define it, resulting in The PREMIS Data Dictionary for Preservation Metadata, which has become a de facto standard that defines core metadata needed by most preservation repositories. The use of standards is important as it supports the development of a community of best practice; it helps practitioners learn from the insights of others, so that they do not inadvertently overlook key metadata in their own practice; it allows for development of tools to make metadata creation and management easier; and it enables organizations to more easily exchange information with each other.


History

The PREMIS working group was created to further the work of an earlier initiative sponsored by the
Online Computer Library Center OCLC, Inc., doing business as OCLC, See also: is an American nonprofit cooperative organization "that provides shared technology services, original research, and community programs for its membership and the library community at large". It was ...
OCLC and the
Research Libraries Group The Research Libraries Group (RLG) was a U.S.-based library consortium that existed from 1974 until its merger with the OCLC library consortium in 2006. RLG developed the Eureka interlibrary search engine, the RedLightGreen database of bibliograp ...
RLG: the Preservation Metadata Framework (PMF) working group. In 2001–2002 the PMF working group outlined the types of information that should be associated with an archived digital object. Their report, ''A Metadata Framework to Support the Preservation of Digital Objects'' (the ''Framework''), proposed a list of prototype metadata elements. At this stage these proposed elements could not be implemented and additional work was needed. In 2003 the PREMIS working group was asked to take the PMF group’s findings further and develop a
data dictionary A data dictionary, or metadata repository, as defined in the ''IBM Dictionary of Computing'', is a "centralized repository of information about data such as meaning, relationships to other data, origin, usage, and format". ''Oracle'' defines it ...
of core metadata for archived digital objects, as well as to give guidance and suggest best practice for
management Management (or managing) is the administration of an organization, whether it is a business, a nonprofit organization, or a Government agency, government body. It is the art and science of managing resources of the business. Management includ ...
: creating, managing, and using the metadata in preservation systems. PREMIS was “charged to define a set of semantic units that are implementation independent, practically oriented, and likely to be needed by most preservation repositories”. The working group consisted of a multi-national roster of more than thirty representatives from the cultural, government, and private sectors. It sought to understand how preservation repositories were actually implementing preservation metadata. A survey was performed on 70 organizations thought to be active in or interested in digital preservation. In December 2004 the PREMIS working group published its report, ''Implementing Preservation Repositories for Digital Materials: Current Practice and Emerging Trends in the Cultural Heritage Community''. The earlier ''Framework'' and the PREMIS Data Dictionary build on the
Open Archival Information System An Open Archival Information System (or OAIS) is an archive, consisting of an organization of people and systems, that has accepted the responsibility to preserve information and make it available for a Designated Community. The OAIS model can ...
(OAIS) reference model. The OAIS information model provides a conceptual foundation in the form of a taxonomy of information objects and packages for archived objects, and the structure of their associated metadata. The ''Framework'', through its deeply detailed mapping of preservation metadata to that conceptual structure, can be seen as an elaboration of OAIS. The PREMIS Data Dictionary, on the other hand, can be seen as a translation of the ''Framework'' into a set of implementable semantic units. The Data Dictionary and OAIS sometimes differ in terminology usage and these are noted in the Glossary. Differences usually reflect the fact that PREMIS semantic units require more specificity than the OAIS definitions provide, which is to be expected when moving from a conceptual framework to an implementation. In May 2005, PREMIS released ''Data Dictionary for Preservation Metadata: Final Report of the PREMIS Working Group''. This 237-page report includes: PREMIS Data Dictionary 1.0: a comprehensive, practical resource for implementing preservation metadata in digital archiving systems; accompanying report (providing context, data model, assumptions); special topics, glossary, usage examples; set of
XML schema An XML schema is a description of a type of XML document, typically expressed in terms of constraints on the structure and content of documents of that type, above and beyond the basic syntactical constraints imposed by XML itself. These constra ...
which was developed to support use of the Data Dictionary. The current Version 3.0 of PREMIS was released in June 2015.


Versions


Entities

The PREMIS data model consists of four interrelated entities: # Object (divided into three subtypes) # Event # Agent # Rights With each semantic unit in the data dictionary categorized in one of these areas. An Intellectual Object entity is a type of Object. It is a set of content that constitutes a discrete, coherent intellectual unit, such as a book or a database. These may be compound objects containing other intellectual entities and may have multiple digital representations.PREMIS Editorial Committee. (2008)
PREMIS Data Dictionary for Preservation Metadata, Version 2.0.
6. URL accessed April 28, 2008.
Descriptive metadata is usually applied at this level; given the proliferation of competing schemes, the working group did not define any further descriptive semantic units and allowed for interoperability through “extension containers” (containers hold a related group of semantic units) that can be used for external schemes. Most of the semantic units listed in the data dictionary relate to Object and Event entities, the former being further divided into three subtypes of file, bitstream, and representation. A file is the level at which most end users are used to working, a “named and ordered sequence of bytes that is known by an operating system.” It includes a variety of file system attributes, rendering it understandable by an operating system, encompassing bitstreams, which are “contiguous or non-contiguous data within a file that has meaningful common properties for preservation purposes.” A representation is, in a sense, the “highest level” of this model, for it may encompass several files in order to properly render the structure and content of an intellectual entity. Not all repositories will be concerned with preserving representations, depending on their purpose and the curatorial body’s need to preserve what might be considered the entity’s digital “intrinsic value.” Furthermore, intellectual entities may have multiple representations within a repository. Events interrelate with objects insofar as they involve actions that have an effect on them or agents ("a person, organization, or software...associated with Events...or with Rights attached to an object") associated with the object. Finally, the inclusion of rights entities responds to an increased awareness of and concern for the legal requirements of copyright and licensing. It also includes information about the specific actions permitted; for example, semantic unit 4.1.6.1, act, “the action the preservation repository is allowed to take,” includes such suggested values as replicate, migrate, and delete.


Data dictionary

PREMIS data dictionary entries include twelve attribute fields, not all of which are applied to every semantic unit (analogous to an "element" in other metadata schemes). In addition to the name and definition of the unit, the fields record such things as rationale for including the unit, usage notes, and examples of how the value might be filled in. Four of the attributes - object category, applicability, repeatability, and obligation - are linked, as the last three are defined for each of the object entity levels of file, bitstream, and representation. The dictionary is hierarchical; some semantic units are contained within others. For example, 1.3 preservationLevel, includes four semantic components, such as 1.3.1 preservationLevelValue and 1.3.2 preservationLevelRole.PREMIS Editorial Committee. (2008)
PREMIS Data Dictionary for Preservation Metadata, Version 2.0.
22-194. URL accessed April 28, 2008.


See also

*
Digital preservation In library and archival science, digital preservation is a formal endeavor to ensure that digital information of continuing value remains accessible and usable. It involves planning, resource allocation, and application of preservation methods and ...
* Preservation metadata * Metadata *
Digital library A digital library, also called an online library, an internet library, a digital repository, or a digital collection is an online database of digital objects that can include text, still images, audio, video, digital documents, or other digital ...
*
Protocol for Metadata Harvesting The Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) is a protocol developed for harvesting metadata descriptions of records in an archive so that services can be built using metadata from many archives. An implementation of OAI-P ...
(OAI-PMH) *
Metadata Encoding and Transmission Standard The Metadata Encoding and Transmission Standard (METS) is a metadata standard for encoding descriptive, administrative, and structural metadata regarding objects within a digital library, expressed using the XML schema language of the World Wid ...
(METS) maintained by the
Library of Congress The Library of Congress (LOC) is the research library that officially serves the United States Congress and is the ''de facto'' national library of the United States. It is the oldest federal cultural institution in the country. The library ...
*
Dublin Core 220px, Logo image of DCMI, which formulates Dublin Core The Dublin Core, also known as the Dublin Core Metadata Element Set (DCMES), is a set of fifteen "core" elements (properties) for describing resources. This fifteen-element Dublin Core has ...
, an ISO metadata standard


References


External links


PREMIS - Official Page (LC)
{{Authority control Digital preservation Preservation (library and archival science) Metadata