Isearch is open-source[further explanation needed] text retrieval software first developed in 1994 by Nassib Nassar as part of the Isite Z39.50 information framework.
One of the limiting factors, however, of the Isearch design was that it was not well suited to handle the extremely large data sets that became popular in the mid to late 1990s.
Isearch was widely adopted and used in hundreds of public search sites, including many high profile projects such as the U.S. Patent and Trademark Office (USPTO) patent search, the Federal Geographic Data Clearinghouse (FGDC), the NASA Global Change Master Directory, the NASA EOS Guide System, the NASA Catalog Interoperability Project, the astronomical pre-print service based at the Space Telescope Science Institute, The PCT Electronic Gazette at the World Intellectual Property Organization (WIPO), Linsearch (a search engine for Open Source Software designed by Miles Efron), the SAGE Project of the Special Collections Department at Emory University, Eco Companion Australasia (an environmental geospatial resources catalog), Australian National Genomic Information Service (ANGIS), the Open Directory Project and numerous governmental portals in the context of the Government Information Locator Service (GILS) GPO mandate (ended in 2005?).
From 1994 to 1998 most of the development was centered on the Clearinghouse for Networked Information Discovery and Retrieval (CNIDR) in North Carolina (Engine core) and BSn in Germany (Doctypes).
As of 2010, the open source version of Isearch is still used on 250+ nodes of FGDC, and by ANZLIC in Australia and selected Geospatial OneStop contributors to facilitate harvesting by GOS, including NOAA, Census Bureau and the Tenn. Field Office of the US Fish and Wildlife Service, among others.