4.1 Introduction
4.1.1 A digital sound recording, whether stored on a mass storage system or on discrete carriers, must be able to be identified and retrieved. An item cannot be considered preserved if it cannot be located, nor linked to the catalogue and metadata record that gives it meaning. There is a need for every digital item to be unambiguously and uniquely named. In ensuring that the digital object is unambiguously and uniquely named the first step in the identification is to determine what is being named, and at what level.
4.1.2 All computer records by their very nature have some sort of system identifier that enables them to be stored without conflict. This identifier may be an acceptable public identifier, but more often than not such identifiers are system oriented and subject to change based on system requirements. There is a subsequent need for a persistent public identifier to maintain an item’s accessibility, to ensure that it can be located and displayed by those who wish to use it so that citations and links made to it continue to provide access to it. There is also a requirement for that identifier to resolve to the item to which it refers regardless of where it has been stored or what its system identifier may have become.
4.1.3 The Resource Description Framework (RDF) standard is an important reference for the identification of digital objects (http://www.w3.org/RDF/ ). RDF is based on the concept of identifying things using Web identifiers called URIs (Universal Resource Identifiers). The identification systems are based on two basic mechanisms. The first is the naming of an item by creating an identifier based on semantics or other rules of labelling such that the identifier will remain attached to the item. In the RDF standard, such identifiers are called URNs (Universal Resource Names). The second is the locator, which is organising a location system so that the item intended to be identified could be found from the locator. In the RDF standard, such identifiers are called URLs (Universal Resource Locator).
4.1.4 There have been many proposed schemes for naming a digital object, some specifically for audio or audiovisual objects, amongst them the EBU Technical Recommendation R99-1999 ‘Unique’ Source Identifier (USID) for use in the <OriginatorReference> field of the Broadcast Wave Format (BWF). Such schemes are intended to provide a unique number within a particular community. Such schemes have not been successful in obtaining universal acceptance.
