• GalaTex XQuery Full-Text Search (XML query text search)
• 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
• DIG Open source web crawling software
• iHOP Information retrieval system for the biomedical domain
• MG full-text retrieval system Now maintained by the Greenstone Digital Library Software Project
• Information Storage and Retrieval Using Mumps

Tags: information retrieval, open source