Digital Library

          A digital library is a library in which wide range of collections are stored in digital formats as opposed to print, micro form, or other media and accessible by computers. The digital content may be stored locally, or accessed remotely via computer networks. A digital library is an information retrieval system of digitally stored contents.

Emergence of Digital Libraries

          In ancient times information stored in palm leaves, were collected and preserved in libraries (e.g. Nalanda Vishwa Vidyalaya in Bihar, Saraswathimahal Library in Tanjore etc.). From 19^th century, after the advent of printing machine, information available in the form of printed books, magazines research journals, documents, diagrams etc. were preserved in libraries and made available for use to the general public. In the later part of the 20^th century, existing information in the print form were transformed into advanced forms such as audio and video tapes, Cassette Discs, Microfilms etc. Libraries were considered as store houses of all types of information. The general publics were permitted to make use of the library either by visiting the books there or take them home on loan for a short period of time. When the applications of computer expanded its fold on human activities, libraries too came under its spell.

          To begin with he catalogue of books available in the library was digitized so that any one could with the help of his personal computer know whether the information needed by him is available in that particular library or not. This facility provided by libraries is called OPAC (Online Public Access System).

As information started pouring, day by day, books too multiplied in their number. as books and other information compilations required large space for their storage and preservation, space-crunch was felt in crowded libraries. In order to overcome this difficulty, publishers soon started to bring out books in C.D. Roms and micro-films. This advanced technologies enabled us to store vast information (books) in much smaller space; searching for information too became easier; time required for search is also very less; retrieved information could also be easily and quickly copied.

          Advancement in information and communication technology and computer applications combined together today to bring out a new dimension in information storage. As more number of people in the society today have basic knowledge and skills in handling computer, they store the needed information in their personal computers, copy them in a separate floppy / pendrive whenever required and carry it with ease to anywhere they go. This trend is becoming increasingly popular and such users often visit the web-sites in the internet, to pick up the information / data they need. Digital libraries are thus born to fulfil the needs of such people who rely on computers and the internet, to get at the information they need.

          Today information stored in the digital form are available in web-sites as books, journals, research articles, news bulletins, etc. those who have the facility of a computer and a proper internet connection can visit or download the information stored in web-sites, by using a proper browser. At present, navigators like 'Internet Explorer', 'Netscap Navigators' etc. are used internationally for browsing. The digital information storied in Web-sites is not only in text form but have also animation, natural and virtual environments, audio and video effects etc. and hence rich in quality. In any field on any topic, one can locate various kinds of information designed and stored as 'Blogs' in the Websites, which could be visited at any time from anywhere.

          Thus it could be summarized that digital library is a storehouse where information needed for users belonging to various fields are digitally stored and made available 'on-line', It is not only a wide range of collections and organizations, but also the on-line collection of information is managed by and made accessible to a community of users.

          Those websites alone which fulfil these two conditions viz. (i) digital storing of information (ii) online information is managed and made accessible to a community of users, are called digital libraries; and not all websites.

Advantages of Digital Library

1.    No Physical boundary.

2.    The user of a digital library need not go to the library physically; people from all over the world can gain access to the same information, as long as an internet connection is available.

3.    Round the clock availability of information.

4.    Multiple access: The same resources can be used simultaneously by any number of institutions and patrons.

5.    Information Retrieval: The user is able to use any search term (word, phrase, title, name, and subject) to search the entire collection.

6.    Preservation and Conservation: Unlike traditional books, digitized materials do not fall to degradation due to repeated visit of numerous users or their downloading.

7.    Space: Traditional libraries are limited by storage space; digital libraries have the potential to store much more information, simply because digital information requires very little physical space to contain it. As such, the cost of maintaining a digital library is much lower that that of a traditional library.

8.    Maintenance Cost: A traditional library must spend large sums of money paying for staff, book maintenance, rent for the building and cost of purchasing additional books. Digital libraries do away with these fees. Both type of libraries require cataloguing input to allow users to locate and retrieve material.

9.    Digitized materials are rich as they contain audio, video, and animation.

10.           Large chunk of information could be reached at a single source.

11.           Searching and downloading information take place rapidly in digital libraries.

12.           In downloading information, there is no chance for mistake or confusion to take place.

13.           The most significant aspect of digital library is that the information available are updated and get refined every day.

14.           Added Value: Certain characteristics of objects, primarily the quality of images may be improved. Digitization can enhance legibility and remove visible flaws such as strains and discolouration.

Demerits of Digital Library

1.    Copyright Confusion: Downloading and distributing information is very easy but there is confusion over the copyright owners. Works in digitized library cannot be shared over different periods of time in the manner of a traditional library. The republication of material on the Web by library. The republication of material on the Web by libraries may require permission from rights holders, and there is a conflict of interest between them and publishers who may wise to create web versions of their content for commercial purposes.

2.    Technological Changes: Technological changes over time and forward migration must be a constant consideration of every library. Migration is a means of transferring an unstable digital object to another more stable format, operating system or programming language. Migration allows the ability to retrieve and display digital objects that are in danger of becoming extinct. This is a rather successful short-term solution for the problem of aging and obsolute digital formats, but with ever-changing nature of computer technologies, migratin becomes this never-ending race to transfer digital objects to new and more stable formats. Migration is also flawed in the sense that when the digital files are being transferred, the new platform may not be able to capture the full integrity of the original object.

3.    Space required to record pictures and diagrams in the digital format is more than for the text and consequently involves high cost. Collection of information in a library is a continuous process. If libraries own the responsibility of updating information, digitizing pictures etc. or conserving information through forward migration then confusion results about who is to own the recurring cost of preservatin.

4.    Digitizing pictorial information / data is highly expensive.