Preservation of Digital Resources:
Digital preservation is a process by which data is preserved in digital form in order to ensure usability, durability and intellectual integrity of the information contained therein. A more precise definition as given by Kelly (1999), “The storage, maintenance, and accessibility of digital object (include any digital material such as a text document, an image file, a multimedia CD-ROM or a database) over the long term, usually as a consequence of applying one or more digital preservation strategies. The term digital preservation is used in different ways. Fresco (1999) defines the terms as, “the storage, maintenance and access to digital objects over the long term”. The key point of this definition is that it is about ensuring that intellectual content, which is already in digital form, remains accessible to future generations.
1. Preservation of Digital Resources:
“Digital Preservation” means taking steps to ensure long term access to digital documents. Unlike print publications, digital preservation is more complex as one has to take care of many aspects of the documents such as content, presentation, functionality, authenticity, etc. At the time of selection and acquisition only one must think of the preservation of digital resources. Digital technology, as well as other technologies such as the Internet and Web technologies, are continuously changing due to the up-gradation of software and hardware, the proliferation of standards and protocols for file formats, network interfaces, storage media, and devices, etc. As a result of which there is constant danger of “techno-obsolescence”.
Issues Relating to Digital Preservation
The fundamental problem of preserving electronic documents or “digital objects” stems from the nature of the objects themselves. Digital objects are accessible only through combinations of hardware and software. The hardware and software become obsolete in cycles of less than three years. Ensuring ongoing access, therefore, requires currency with technology changes, and moving digital objects from obsolete to current file formats, storage media, operating systems and so on.
1. Technological Obsolescence:
Innovation in computer hardware, storage, and software industries continues at a rapid pace, usually yielding greater storage and processing capacities at a lower cost. Devices, processes, and software for recording and storing information are being replaced with new products and methods at regular three to five years cycles, driven primarily by market forces. Records created in digital form in the first instance and those converted retrospectively from paper or microfilm to digital form are equally vulnerable to technological obsolescence. It is costly and difficult for vendors to assure that their products are either backwardly compatible with the previous version or that they can inter-operate with competing products.
2. Migration of Digital Information:
Migration is the periodic transfer of digital materials from one hardware or software configuration to another or from one generation of computer technology to a subsequent generation. The purpose of migration is to preserve the integrity of digital objects and to retain the ability for clients to retrieve, display, and otherwise use them in face of constantly changing technology. It has always been a problem with the preservationists to make an exact copy or replica of databases or other digital objects as hardware and software change makes the object incompatible with the new generation of technology.
3. Legal and Organizational Issues:
The barriers to decisive preservation action are caused by widespread uncertainty about legal and organizational requirements for managing the intellectual property that digital information presents. Any preservation strategy will require permission from the copyright holders. Permission could be needed to digitize a work of art; store the digitized image in an archive; move the digital image between archives; grant permission for authorization to the digital image; change file formats; change storage media; and also for the possible deletion of the digital image.
For digital preservation, the organizational effort-the process of building infrastructure-necessarily involves multiple, interrelated factors such as institutions, services, technologies, and qualified personnel capable of supporting a distributed system of the digital archives. The effort to meet the cultural imperative of digital preservation required a complex iteration and reiteration.
5. Conceptual Frame Work or Standards:
Another challenge is the absence of established standards, protocols, and proven methods for preserving digital information. There is a lack of adequate research in areas such as framing key problems associated with digital information, defining critical issues, establishing standards for digital preservation, etc. Hedstrom & Montgomery (1998), in their survey Digital Preservation Needs and Requirements in RLG (Research Library Groups) Member Institutions’ found that majority of member institutions have not developed policies for the acquisition, storage, freshing and migration of digital information and have not developed methods to preserve digital information.
Hence preservation policy for digital resources is of prime importance and should take care of the following aspects
- Preservation of digital resources as different levels depending on its usability functionalities;
- Continuous reviewing of the digital resources ensuring long term access to them;
- Weeding out obsolete information and invalid websites.
Preservation of digital resources can be possible in three ways.
Preservation of digital resources can be possible in three ways.
i. Technology preservation: The older technology can be preserved for viewing digital objects in their original formats but it is not feasible in the long term due to cost, space and technical support requirements. e.g. Hardware.
ii. Technology emulation: It refers to creating new software that copies the operations of older hardware and software thus ensuring it’s originality in terms of physical presence, content, and functionality. Some digital resources are highly dependent on particular hardware or software. Emulation techniques can be useful in such cases. However, emulation for preserving digital resources over the long term has not been tested.
iii. Data migration: Migration covers a range of activities to periodically copy, convert or transfer digital information from a medium that is becoming obsolete or physically deteriorating to a newer one ( e.g. Floppy disk to CD-ROM), and/or converting from one format to another (e.g. Microsoft Word to ASCII), and/or moving documents from one platform to another (e.g. VAX to UNIX). Migration certainly preserves the physical presence and the content of the digital object.
Strategies for Digital Preservation
Digital preservation is defined as the storage, maintenance, and access to digital objects over the long term, usually as a consequence of applying one or more digital preservation strategies. A digital preservation strategy should be evaluated against a set of criteria such as technological feasibility, cost-effectiveness, effectiveness in retaining the essential attributes of digital information, acceptance by creators, managers of digital repositories, and user communities. Hendly (1998) identified three potential strategies for ensuring long term access to digital information. These include:
1. Technology preservation,
2. Technology emulation and
3. Digital information migration.
However, Russel (1999) and Bullock (1999) have accepted “output to the permanent paper of microfilm” as a low-tech strategy for preservation
Technology Preservation: Another method for ensuring ongoing access to digital objects would be to simply keep older technology available for use. The most obvious way of ensuring that the object is preserved as it was created is to preserve the environment used to create and use resources, that preserve the software and hardware environment that was used to access the resource when it was created. For some digital objects, this may be the best solution at least in the short-run because it ensures that the material is accessible by preserving the access tools as well as the object itself.
Digital Preservation: Building on the work of the Commission on Preservation and Access (CPA) CLLR and the DLF remain committed to maintaining long-term access to the digital intellectual and scholarly record. They have a particular interest in practical initiatives and in research into most poorly understood areas. This page links to CUR, DLF, and CPA preservation initiatives, research reports, and related information resources.
- Full Reference Article: Selvakumar, A. (2002). Acquisition and preservation of digital library resources. University.