In 2003 the OCLC and RLG established Preservation Metadata: Implementation Strategies
(PREMIS), an international working group.
Preservation metadata is the information infrastructure that supports all processes associated with digital preservation (Lei Zeng and Qin, 60). In the 2008 OCLC-RLG report: “The Data Dictionary defines preservation metadata [as] that [which]:
• Supports the viability, renderability, understandability, authenticity, and identity of
digital objects in a preservation context;
• Represents the information most preservation repositories need to know to preserve
digital materials over the long-term;
• Emphasizes “implementable metadata”: rigorously defined, supported by guidelines for
creation, management, and use, and oriented toward automated workflows; and
• Embodies technical neutrality: no assumptions made about preservation technologies,
strategies, metadata storage and management, etc.
In addition to the Data Dictionary, the working group also published a set of XML schema to
support implementation of the Data Dictionary in digital archiving systems.”
For an example of this PREMIS xml schema, see http://www.loc.gov/standards/premis/premis.xsd
The PREMIS working group was established to build on the earlier work of another initiative
sponsored by OCLC and 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. However, to make the data implementable, the working group was asked to take the PMF’s work further to incorporate archived digital objects — and thus the PREMIS working group was established.
In the image/graphic above, an intellectual entity is a set of content that is considered a single intellectual unit for purposes of management and description: for example, a particular book, map, photograph, or database. An Intellectual Entity can include other Intellectual Entities; for example, a Web site can include a Web page; a Web page can include an image. An Intellectual Entity may have one or more digital representations. An Object (or Digital Object) is a discrete unit of information in digital form. An Event is an action that involves or impacts at least one Object or Agent associated with or known by the preservation repository. An Agent is a person, organization, or software program/system associated with Events in the life of an Object, or with Rights attached to an Object. The Rights are assertions of one or more rights or permissions pertaining to an Object and/or Agent.
The PREMIS Data Dictionary defines semantic units. Each semantic unit defined in the Data
Dictionary is mapped to one of the entities in the data model. In this sense, a semantic unit may
be viewed as a property of an entity. For example, the semantic unit size is a property of an
Object entity. Semantic units have values: for a particular Object the value of size might be
“843200004.”
The intention of preservation metadata is to make the metadata of digized/digital objects self-documenting over time. Preservation metadata is used to document the attributes of digitized materials in a consistent way that makes it possible to identify the provenance of an item as well as the terms and conditions that govern its distribution and use (Lei Zeng and Qin, 60).
For more detailed information and to see how it is implemented, see the 237-page report (v.2) below, under Sources, or the XML shema link.
Sources:
http://www.loc.gov/standards/premis/ (The updated dealings/decisions of the working group)
http://www.oclc.org/research/projects/pmwg/premis-final.pdf (v.1, 2005)
http://www.loc.gov/standards/premis/v2/premis-2-0.pdf (v.2, 2008)
http://www.oclc.org/research/projects/pmwg/(OCLC portal)
http://www.loc.gov/standards/premis/premis.xsd (XML schema)
Lei Zeng, Marcia and Jian Qin. “Current Standards,” in Metadata (New York: Neal-Schumann Publishers, Inc.: 2008), 60-63.
http://www.idealliance.org/papers/extreme/proceedings/html/2007/Ramalho01/EML2007Ramalho01.html (Relational database preservation through XML Modeling)