Information Storage and Retrieval systems

An information storage and retrieval system (ISRS) is a network with a built-in user interface that facilitates the creation, searching, and modification of stored data.

Characteristics of an ISRS include lack of centralization, graceful degradation in the event of hardware failure, and the ability to rapidly adapt to changing demands and resources. The lack of centralization helps to ensure that catastrophic data loss does not occur because of hardware or program failure, or because of the activities of malicious hackers. Graceful degradation is provided by redundancy of data and programming among multiple computers. The physical and electronic diversity of an ISRS, along with the existence of multiple operating platforms, enhances robustness, flexibility, and adaptability. In addition to these features, some ISRSs offer anonymity, at least in theory, to contributors and users of the information.

There are several basic types of information-storage-and-retrieval systems. Document-retrieval systems store entire documents, which are usually retrieved by title or by key words associated with the document. In some systems, the text of documents is stored as data. This permits full text searching, enabling retrieval on the basis of any words in the document. Database systems store the information as a series of discrete records that are, in turn, divided into discrete fields (e.g., name, address, and phone number); records can be searched and retrieved on the basis of the content of the fields (e.g., all people who have a particular telephone area code). Reference-retrieval systems store references to documents rather than the documents themselves. Such systems, in response to a search request, provide the titles of relevant documents and frequently their physical locations. Such systems are efficient when large amounts of different types of printed data must be stored. They have proven extremely effective in libraries, where material is constantly changing