Digital preservation

In library and archival science, digital preservation is a formal endeavor to ensure that digital information of continuing value remains accessible and usable. It involves planning, resource allocation, and application of preservation methods and technologies, and it combines policies, strategies and actions to ensure access to reformatted and 'born-digital' content, regardless of the challenges of media failure and technological change. The goal of digital preservation is the accurate rendering of authenticated content over time.The Association for Library Collections and Technical Services Preservation and Reformatting Section of the American Library Association, defined digital preservation as combination of 'policies, strategies and actions that ensure access to digital content over time.' According to the Harrod's Librarian Glossary, digital preservation is the method of keeping digital material alive so that they remain usable as technological advances render original hardware and software specification obsolete. In library and archival science, digital preservation is a formal endeavor to ensure that digital information of continuing value remains accessible and usable. It involves planning, resource allocation, and application of preservation methods and technologies, and it combines policies, strategies and actions to ensure access to reformatted and 'born-digital' content, regardless of the challenges of media failure and technological change. The goal of digital preservation is the accurate rendering of authenticated content over time.The Association for Library Collections and Technical Services Preservation and Reformatting Section of the American Library Association, defined digital preservation as combination of 'policies, strategies and actions that ensure access to digital content over time.' According to the Harrod's Librarian Glossary, digital preservation is the method of keeping digital material alive so that they remain usable as technological advances render original hardware and software specification obsolete. Archival appraisal (or, alternatively, selection) refers to the process of identifying records and other materials to be preserved by determining their permanent value. Several factors are usually considered when making this decision. It is a difficult and critical process because the remaining selected records will shape researchers' understanding of that body of records, or fonds. Appraisal is identified as A4.2 within the Chain of Preservation (COP) model created by the InterPARES 2 project. Archival appraisal is not the same as monetary appraisal, which determines fair market value. Archival appraisal may be performed once or at the various stages of acquisition and processing. Macro appraisal, a functional analysis of records at a high level, may be performed even before the records have been acquired to determine which records to acquire. More detailed, iterative appraisal may be performed while the records are being processed. Appraisal is performed on all archival materials, not just digital. It has been proposed that, in the digital context, it might be desirable to retain more records than have traditionally been retained after appraisal of analog records, primarily due to a combination of the declining cost of storage and the availability of sophisticated discovery tools which will allow researchers to find value in records of low information density. In the analog context, these records may have been discarded or only a representative sample kept. However, the selection, appraisal, and prioritization of materials must be carefully considered in relation to the ability of an organization to responsibly manage the totality of these materials. Often libraries, and to a lesser extent, archives, are offered the same materials in several different digital or analog formats. They prefer to select the format that they feel has the greatest potential for long-term preservation of the content. The Library of Congress has created a set of recommended formats for long-term preservation. They would be used, for example, if the Library was offered items for copyright deposit directly from a publisher. In digital preservation and collection management, discovery and identification of objects is aided by the use of assigned identifiers and accurate descriptive metadata. An identifier is a unique label that is used to reference an object or record, usually manifested as a number or string of numbers and letters. As a crucial element of metadata to be included in a database record or inventory, it is used in tandem with other descriptive metadata to differentiate objects and their various instantiations. Descriptive metadata refers to information about an object's content such as title, creator, subject, date etc... Determination of the elements used to describe an object are facilitated by the use of a metadata schema. Extensive descriptive metadata about a digital object helps to minimize the risks of a digital object becoming inaccessible. Another common type of file identification is the filename. Implementing a file naming protocol is essential to maintaining consistency and efficient discovery and retrieval of objects in a collection, and is especially applicable during digitization of analog media. Using a file naming convention, such as the 8.3 filename, will ensure compatibility with other systems and facilitate migration of data, and deciding between descriptive (containing descriptive words and numbers) and non-descriptive (often randomly generated numbers) file names is generally determined by the size and scope of a given collection. However, filenames are not good for semantic identification, because they are non-permanent labels for a specific location on a system and can be modified without affecting the bit-level profile of a digital file. The cornerstone of digital preservation, 'data integrity' refers to the assurance that the data is 'complete and unaltered in all essential respects'; a program designed to maintain integrity aims to 'ensure data is recorded exactly as intended, and upon later retrieval, ensure the data is the same as it was when it was originally recorded'.