Text Retrieval Packages:
Text retrieval comprises storage and subsequent retrieval of rat girds, essentially textual rather than numerical, tabular or graphical. Although, each of the earlier mentioned software can be used for text retrieval purposes to some extent. there re special purpose packages which are written specially for the type of retrieval function related to libraries and information centres. The characteristic features of such software packages are: (a) the software is normally self-contained and can be set up with a minimum involvement of a computer specialist staff; (b) the records in this software are independent, of variable length and are composed mostly of natural language texts; (c) access to data is by content rather than by structural position; (d) primary access is through inverted file of text terms drawn from the records as they are placed on the database. Thus, an important feature of the package Is user interfaces, which allows a non-programmer to understand and use them directly. Search and indexing facilities are the most important features of this type of software.