INFORMATION RETRIEVAL SYSTEM

                      An information retrieval System

The term ‘information retrieval’ was coined by Calvin Mooers in 1950. It gained popularity in the research community from 1961 onwards, when computers were introduced for information handling. The term information
retrieval was then used to mean retrieval of bibliographic information from stored document databases. But those information retrieval systems (IRS) were document retrieval systems. These were designed to retrieve information about the existence (or non-existence) of bibliographic documents relevant to a user’s query. In other words, early IRS were designed to retrieve an entire document (a book, an article, etc.) in response to a search request. Although this is what today’s IRS do, but over the years, many advanced techniques have been developed and applied to design the IRS. Over the years, the connotation of information retrieval has changed and it has been variously denoted by
information professionals and researchers. Some of these include, information storage and retrieval, information organization and retrieval, information processing and retrieval, text retrieval, information representation and retrieval and information access.

The principal function of any library is to make available to the users, the information they need. In order to fulfill this function, the information which is stored in the library must be retrieved from the library database. Information
retrieval (IR) is the activity of obtaining information resources relevant to an information need from a collection of information resources. Information retrieval is the process of selecting information from the stored information.
The process is becoming increasingly dependent on computers and telecommunications technology. The design of information retrieval systems has presently become an important area of applied information technology.

INFORMATION RETRIEVAL SYSTEM
The concept of Information Retrieval System (IRS) is self-explanatory from the terminological point of view and refers to a ‘system which retrieves information’. IRS is concerned with two basic aspects:

(i) How to store information, and

(ii) How to retrieve information.
One may simply denote such a system as one that stores and retrieves information. IRS is comprised of a set of interacting components, each of which is designed to serve a specific function for a specific purpose. All these
components are interrelated to achieve a goal. The concept of IR thus is based on the fact that there are some items of information which have been organized in a suitable order for easy retrieval.
An information retrieval system is designed to analyze, process and store sources of information and retrieve those that match a particular user’s requirements. Modern information retrieval systems can either retrieve
bibliographic items or the exact text that matches a user’s search criteria from a stored database of documents. IRS originally meant text retrieval systems as they were dealing with textual documents. Modern information retrieval
systems deal not only with textual information but also with multimedia information comprising text, audio, images and video. Thus, modern information retrieval systems deal with storage, organization and access to text, as well as
multimedia information resources.
Thus, an IR system is a set of rules and procedures, for performing some or all of the following operations:
a) Indexing (or constructing of representations of documents);
b) Search formulation (or constructing of representations of information
needs);
c) Searching (or matching representations of documents against representations
of needs); and
d) Index language construction (or generation of rules of representation)
So information retrieval is collectively defined as a “science of search” or a process, method and procedure used to select or recall, recorded and/or indexed information from files of data.