The THREDDS Data Server (TDS) is a web server that provides metadata and data access for scientific datasets. It integrates THREDDS Catalog Services with data serving capabilities, including OPeNDAP, HTTP file serving, and OGC Web Coverage Server (prototype). In conjunction with the LDM, it can provide pull access to the IDD datastream. It can also be used to serve data archives.
The TDS is 100% Java, open source, and runs as a Tomcat web server application. TDS data serving capabilities are built on top of Unidata's netCDF-Java / CDM library. The CDM data model combines the NetCDF-3, DAP2, and HDF5 data models, into what is called the Common Data Model (CDM). It has a pluggable "I/O Service Provider" architecture that allows it to read various file formats into the CDM, including NetCDF, HDF5, GRIB, NEXRAD levels 2 and 3, and others, as well as datasets served through the OPeNDAP protocol. The TDS then builds data services on top of the CDM.