It is a Java-based open source XML repository with search and discovery system.
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The Digital Discovery System (DDS) is a Java-based open source XML repository, search and discovery system that is built with Lucene.
Its repository is accessed through Web service APIs that may be used for a wide variety of applications. The Digital Discovery System (DDS) software is developed by Digital Learning Sciences (DLS) at the University Corporation for Atmospheric Research (UCAR). It is a component of the NSDL EduPak software platform and is also distributed separately as a stand-alone repository system.
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