“Digital preservation is the active management of digital content over time to ensure ongoing access.”1 It is an integral part of a larger process of curation, which consists of the activities across the content lifecycle described throughout this textbook: selection and appraisal, description, ongoing care and management, long-term access, and/or deaccessioning/disposal.
Without active management which includes many of the activities outlined in this chapter, digital assets and their associated content are at risk, potentially through media failure, human error, inaccessibility due to format obsolescence, or barriers to discoverability due to poor metadata. The functions of digital preservation reduce these risks and together help to ensure that content remains accessible over time.
At the heart of a preservation strategy is risk management. The opportunities for loss or damage to digital collections is inherent in providing access to users, who may include digital collections managers, IT staff, students, the public, and others. A preservation strategy can be an effective way to mitigate these risks to the greatest extent possible.
The nature of risks are varied and may be human-generated, mechanical, or natural. The human risks to technology may be purposeful (file formats are not selected for migration, metadata is not captured), nefarious (viruses, cyber-attacks), or accidental (deletions, misfiling or misnaming files). Organizational risks include insufficient planning and policies, which lead to a loss of or lack of sustainable funding to support trained staff and/or appropriate technologies. Risks may also be mechanical, such as when files change at the bit level without human awareness or media and storage fail. Risks may also come from nature; floods and fires can destroy electronic media on which files are stored.
Over time, risks evolve based on the organization and its resources as well as industry-wide technical changes. As risks change, how institutions identify, respond, and monitor them must change, too. Successful preservation strategies must be flexible, yet cautious, to be able to react to risk effectively. Through planning and management, risks can be mitigated as they emerge.
Due to the varied nature of risks to digital assets, it is important that digital preservation be approached from a programmatic standpoint with administrative support that makes preservation a priority. One approach to thinking about preservation management is illustrated by the concept of the “three-legged stool,” in which the organizational infrastructure, technological infrastructure, and resources all have equal footing to create a stable digital preservation program.Nancy McGovern’s Digital Preservation Management: Implementing Short-term Strategies for Long-term Problems describes these three interlocking structures as follows:
Determining the “what” (organizational infrastructure), the “how” (technological infrastructure), and the “how much” (resources framework) helps to identify an institution’s needs for a sustainable digital preservation program.
Many industries employ standards to make certain they comply with accepted practice, ensure the safety of their customers and employees, and provide a foundation upon which new technologies can be built. Two international standards documents serve as the cornerstone for the management of digital collections, guiding institutions in the development of sustainable preservation programs and serving as benchmarks for institutions that are maintaining preservation management technologies. These are:
The Open Archival Information System (OAIS) reference model is a conceptual framework for an archival system dedicated to preserving and maintaining access to digital assets over the long-term. Because it is a conceptual model, it is not inherently prescriptive. Instead of specifying technology, staffing, or resources, it provides guidance about best practice for building a sustainable preservation environment. OAIS states that archival storage is necessary, but does not specify how that storage will be implemented, the technology required, or how many staff are needed to maintain it. Likewise, access is a component of the OAIS model, although how access is provided will be unique to each organization. Each component represents a process within a system but not the specific resources and technology required to support that process.
|Open Archival Information System (OAIS) reference model.|
The framework takes into account producers (creators) of content (and their embodiment as file-based assets and data that will be preserved); the system (technology, workflows) in which the content is preserved; the administration, management, and preservation planning structure that administers the program; and the consumers (users) that will use the content at some point in the future. Content is packaged in different formats throughout its lifecycle (reflected in the orange ovals in the graphic above):
The value of OAIS is that it provides a model for functions that should occur in a preservation environment and the types of content that must be managed over time. It is an example of a holistic approach to digital preservation, taking into account not only the technology but also the people, resources, and organization as well. Compare this conceptualization to the three-legged stool analogy above.
ISO 16363 is the international standard that describes the characteristics of a trustworthy digital repository (TDR). It includes categories of metrics that identify the individual components that together comprise a TDR. The OAIS framework is the basis for the TDR. The expectation is that any TDR will embody the OAIS model, including a robust submission and ingest process, an archival storage and data management system, and an access component—all overseen by a fully developed organizational and management structure that ensures programmatic longevity and stability. See the figure above to see how these facets interact. Digital objects in ISO 16363 are referred to as “information packages,” as in the OAIS standard. Other vocabulary from OAIS appear in the standard as well.
While the standard was developed to provide a framework for certifying a digital preservation program as “trustworthy,” the reality is that the great majority of institutions will probably not attain certification. Instead, many organizations use the standard’s 109 metrics to guide development and growth of their program and archive and to focus energy and resources on areas for improvement.
Standards offer comprehensive guidance on the making of highly functional and robust digital preservation environments. However, implementing these standards can be a major undertaking, requiring significant resources and cooperation from numerous stakeholders. If an organization lacks the resources to build a local system that meets these standards, there are a number of alternatives available to it, but these standards should still be consulted to provide guidance in choosing the right option.
Look for partnership organizations. Many, often larger, organizations have built their digital preservation infrastructure with standards in mind. Partnering with them to deposit into their archive might be a more sustainable option than building your own. Review a partner organization’s documentation and talk to its staff to understand their approach to digital preservation and whether it complies with OAIS and TDR.
Consider consortial or partnership organizations. Organizations like DPN, MetaArchive, and others have built communities around their digital preservation services. They work together to ensure that these services are built within the ISO framework.
Purchase preservation storage services. DuraCloud and Preservica are just two of several digital preservation products built with guidance from the ISO standards.
No matter which direction an organization takes--building its own preservation system or looking outward for services--the ISO standards should be kept in mind. Whatever the approach, standards-based decision making will help to build a robust and sustainable digital preservation program.
About Digital Preservation. Library of Congress.
“Definition of Digital Preservation.” Association for Library Collections and Technical Services. http://www.ala.org/alcts/resources/preserv/defdigpres0408
“Digital Preservation.” Digital Preservation Handbook.
“What is Digital Curation?” Digital Curation Centre.
ISO 14721:2012, Space data and information transfer systems -- Open archival information system (OAIS) -- Reference model.
ISO 16363:2012, Space data and information transfer systems -- Audit and certification of trustworthy digital repositories.
Data Seal of Approval. Guidelines 2014-15.
National Digital Stewardship Alliance (NDSA) Levels of Digital Preservation.
Section 2: Organizational Infrastructure ›