The core technical registry supports a number of specific services: The PRONOM registry provides a searchable web database of technical information about file formats, the software tools required to access them, and the technical environments required to access them. Users can search for formats and software using a variety of criteria, such as format or software name and
file extension. PRONOM also holds information about support periods for software products, and can also be queried on this basis. In addition to on-screen viewing, registry information can be exported in
XML,
CSV and printer-friendly formats. The PRONOM website allows users to submit new information for inclusion in PRONOM.
The PRONOM Persistent Unique Identifier (PUID) scheme The PRONOM Persistent Unique Identifier (PUID) is an extensible scheme of persistent, unique and unambiguous
identifiers for records in the PRONOM registry. Such identifiers are fundamental to the exchange and management of digital objects, by allowing human or automated user agents to unambiguously identify, and share that identification of, the representation information required to support access to an object. This is a virtue both of the inherent uniqueness of the identifier, and of its binding to a definitive description of the representation information in a registry such as PRONOM. At present, the PUID scheme is limited to one particular class of representation information: the
format in which a digital object is encoded. Formats were considered a particular priority for such a scheme, as no existing, universally applicable system provides for this.
Unix magic numbers and
Macintosh data forks do provide some of this functionality, but the same is not true within
MS-DOS or
Windows environments. The three-character
file extension is neither standardised nor unique, and is interpreted differently by different environments. Equally, the
IANA MIME-type scheme does not provide sufficient granularity or coverage to satisfy the requirements for unique identifiers. The PUID scheme has been developed for the single purpose of providing such identifiers. The scheme has been adopted as the recommended encoding scheme for describing file formats in the latest version of the
UK e-Government Metadata Standard. The scheme is designed to be extensible, and may be expanded in future to include other classes of representation information in PRONOM, such as
compression methods,
character encoding schemes, and
operating systems. PUIDs can be expressed as
Uniform Resource Identifiers using the info:pronom/ namespace, details of which are available from the
info URI registry. Neither the PUID scheme, nor its expression as an info URI, supports any inherent dereferencing mechanism, i.e. a PUID does not resolve to a
Uniform Resource Locator. However, The National Archives is planning to develop a range of services to expose PRONOM registry content, including a resolution service for PUIDs.
DROID DROID (Digital Record Object Identification) is a software tool developed by The National Archives to perform automated batch identification of file formats. It is one of a planned series of tools utilising PRONOM to provide specific digital preservation services. DROID uses internal (byte sequence) and external (file extension) signatures to identify and report the specific file format versions of digital files. These signatures are stored in an
XML signature file, generated from information recorded in the PRONOM technical registry. New and updated signatures are regularly added to PRONOM, and DROID can be configured to automatically download updated signature files from the PRONOM website via
web services. DROID allows files and folders to be selected from a file system for identification. After the identification process had been run, the results can be output in
XML,
CSV or printer-friendly formats. DROID is a platform-independent
Java tool. It includes a documented, public
API, and can be invoked from both
GUI and
command line interfaces.
Future services Proposed future services include format risk assessments and preservation planning, and the automated generation of migration pathways for converting between formats. == See also ==