A1. Definition of Key Terms

Access Master Copy – is a working copy of the preservation master and is the source file for all other derivatives.

Checksum - is a file generated from digital data for the purpose of detecting accidental errors that may have been introduced during its transmission or storage. The integrity of the data can be checked at any later time by recomputing the checksum and comparing it with the stored one. If the checksums match, this shows that the file has not been altered (either intentionally or unintentionally).

Collection – is a general term to describe a body of records, and may include documents, photographs, audio/visual material, maps, etc., in both physical and electronic forms.

Content – is information contained in or on a resource that can be copied by traditional copying processes or digitization. For audio/visual material, the content is the signal encoded in the sound recording. For a photograph, it is the image itself and not the medium the image is held on, i.e. paper, glass, or plastic. For a digital photograph, content is the image and embedded metadata.

Data integrity - refers to the trustworthiness of system resources over their entire life cycle.

Derivative/Surrogate Copy/Version – is a copy that has been derived from the access master for purposes of access such as screen viewing, web delivery, printing, thumbnail galleries, etc.

Digital Asset/Resource – is a digital file that is considered to have value. It can be either “born digital” or the result of the digitization of information content held on an analogue medium, e.g. audio tape, film, etc.

Digital Object – Digital data stored in binary format, consisting of a bit-stream and relevant metadata. Digital objects can include text, photographs, audio files, and videos.

Digital Preservation – is the managed activities necessary for ensuring both the long-term maintenance of digital information and the continued accessibility of its contents. To support digital preservation, it is critical to capture administrative, structural and technical data associated with each object (see metadata).

Digitization – is the process of copying analogue material in any form (text, photographs, voice, etc.) to a digital file form using a device such as a scanner, a camera, or any other electronic device.

Electronic document management system (EDMS) - is software that manages the creation, storage, and control of semi-structured documents.

Lossless formats - are file formats that are stable and therefore compatible with long-term preservation efforts. In general, these formats have the following characteristics: openly documented; supported by a range of software platforms; widely adopted; lossless data compression or no compression; non-proprietary; and does not contain embedded files or embedded programs.

Master File - represents the highest quality version/copy possible, and has permanent value and should be managed in an appropriate environment. Once preservation masters are produced and an access copy created, they are not handled. Access masters are the working copies of the preservation master from which all other derivative files are created.

Metadata – Metadata is structured information that describes, explains, locates, or otherwise makes it easier to retrieve, use, or manage an information resource. Metadata is often called data about data or information about information. It includes all cataloguing or indexing information created to locate, describe and manage the preservation of a resource. For example, metadata recorded for a digital image or photograph would include data about the content of the image, the photographer, the date of creation, date(s) of modification, technical information such as resolution, file type, file format, and its relationship with other related files and their locations.

Metadata can be grouped into general categories, including, but not limited to:

Administrative metadata provides information to help manage a resource, such as when and how it was created, file type and other technical information, and who can access it. There are several subsets of administrative data; two that sometimes are listed as separate metadata types are:
i. Rights management metadata, which deals with intellectual property rights,
ii. Preservation metadata, which contains information needed to archive and preserve a resource.
Descriptive metadata describes a resource for purposes such as discovery and identification. It can include elements such as title, abstract, author, and keywords. For digital resources, descriptive metadata is the information used for the indexing, discovery and identification of a resource. Examples include Dublin Core (DC), and Canadian Rules for Archival Description (RAD).
Structural metadata indicates how compound objects are put together, for example, how pages are ordered to form chapters. For digital resources, structural metadata is the information used to display and navigate digital resources; information on the internal organization of the digital resource; information on viewer or reader plug-in needed to open the digital resource.

Non-proprietary format - a file format where the mode of presentation of its data is transparent and/or its specification is publicly available. Open formats are ordinarily standards fixed by public authorities or international institutions whose aim is to establish norms for software interoperability. There are cases of open formats promoted by software companies which choose to make the specification of the formats used by their products publicly available.

Preservation – refers to activities undertaken to repair or treat damaged materials, activities undertaken to prevent future damage or degradation of materials, and activities associated with maintaining the content of materials for use.

Preservation Master Copy –is the “archival quality” digital copy of material that is stored securely on a physical format or carrier, e.g. compact disc, DVD, magnetic tape, or digital file format, which is likely to be accessible in the future. It may be duplicated in an emerging physical or digital format, to protect its content and structure over time and can serve as a template for producing derivatives or performing other preservation actions.

Preservation Methods/Strategies – include 3 main methods for preserving digital media: migration, encapsulation, emulation, and software and hardware archiving.

  • Migration – involves ensuring that the digital information is re-encoded in new formats before old formats become obsolete.
  • Emulation – involves programming computers to emulate older, obsolete computer platforms and operating systems.
  • Software and Hardware Archiving – involves preserving the original software and hardware that was used to create the information so that it can be accessed in the future.

Proprietary format - a file format where the mode of presentation of its data is opaque and its specification is not publicly available. Proprietary formats are developed by software companies in order to encode data produced by their applications: only the software produced by a company who owns the specification of a file format will be able to read correctly and completely the data contained in this file. Proprietary formats can be further protected through the use of patents and the owner of the patent can ask royalties for the use or implementation of the formats in third-party's software.