forms with users whose applications require greater performance, and the tip associated the most powerful computational platforms with the users requiring the greatest performance for “hero” applications. The same approach can be used to create a Data Pyramid (see Figure 2) to frame today’s digital information and stewardship options.

The Data Pyramid outlines the spectrum of data-collection and data-stewardship alternatives. The bottom includes data of individual (“local”) value whose stewards focus primarily on individual needs (such as personal tax records and digital family photographs and videos). We back this up on our hard drives, with an additional copy off-site if we are methodical, but little of this data will ever be considered of great societal value.

At the top is data of widespread and/ or societal value whose stewards are primarily public-interest institutions (such as government agencies, libraries, museums, archives, and universities). Included are official records, data infeasible or too expensive to replace (such as the Shoah Collection of holocaust survivor testimony, college. usc.edu/vhi/, and digital photographs from the most recent NASA space voyage). Much of it must be preserved over the long term by trusted institutions. It is typically replicated many times, the focus of explicit plans for preservation, and hosted by only the most reliable cyberinfrastructure.

In the middle of the Pyramid is data of value to a specific community whose stewards range from individuals to community groups to companies to public-interest institutions. It includes digital records from your local hospital, scientific research data preserved in community repositories, and digital copies of motion pictures preserved for decades, commercially valuable in the future in the form of, say, the “ director’s cut.” In every sector, groups are beginning to grapple with the responsibility of creating plans for data stewardship that are cost-effective, support reliable digital preservation, and are not subject to the whims of markets and/or community social dynamics.

The Data Pyramid makes it easy to see that multiple solutions for sustainable digital preservation must be

Digital Data Terms
and Conditions

The following definitions are derived from a number of sources, including the american library association ( www.lita.org/ala/), National information assurance glossary ( www.cnss.gov/), and Joint information systems committee Digital information briefing paper ( www.jisc.ac.uk):

aPPRaisaL

evaluation and selection of digital material for long-term curation and preservation, documented policies, guidance, and legal requirements may require that it be done securely;

authentication

security measure designed to establish the validity of a transmission, message, or originator or a means of verifying an individual’s authority to receive specific categories of information;

cuRation

Digital curation, broadly interpreted, is about maintaining and adding value to a trusted body of digital information for current and future use. it builds on the underlying concepts of digital preservation while emphasizing opportunities for added value and knowledge through annotation and continuing resource management;

DiGitaL RiGhts manaGement

The use of technologies to control how digital content is used and reused;

inGest

controlled or secure transfer of material to an archive, repository, data center, or other custodial environment in adherence to documented guidance, policies, or legal requirements;

inteGRity

The condition when data is unchanged from its source and has not been accidently or maliciously modified, altered, or destroyed;

metaData

Documentation relating to data content, structure, provenance (history), and context (such as experimental parameters and environmental conditions). standards for metadata provide a basis for widespread community data sharing; and

PReseRvation action

actions undertaken to ensure the long-term viability and availability of the authoritative nature of digital material. preservation actions should ensure the material remains authentic, reliable, and usable while its integrity is maintained; such actions include validation, assigning preservation metadata, assigning representation information, and ensuring acceptable data structures and file formats.