Information retrieval

Information retrieval (IR) is the art and science of searching for information in documents, searching for documents themselves, searching for metadata which describe documents, or searching within databases, whether relational stand alone databases or hypertext networked databases such as the Internet or intranets, for text, sound, images or data. There is a common confusion, however, between data retrieval, document retrieval, information retrieval, and text retrieval, and each of these have their own bodies of literature, theory, praxis and technologies.

Open source information retrieval systems

• Lemur Language Modelling IR Toolkit
• Lucene Apache Jakarta project
• SMART Early IR engine from Cornell University
• Terrier Information Retrieval Platform
• Xapian Open source IR platform based on Muscat
• Zettair
• ht://dig Open source web crawling software
• MG full-text retrieval system Now maintained by the Greenstone Digital Library Software Project
• Information Storage and Retrieval Using Mumps(Online GPL Text)