The NCBI (National Center for Biotechnology Information) development toolkit, containing various libraries needed by NCBI applications, as well as a software suite containing, amongst other things, NCBI BLAST 2.0. From the README: The NCBI Software Development Toolkit was developed for the production and distribution of GenBank, Entrez, BLAST, and related services by NCBI. We make it freely available to the public without restriction to facilitate the use of NCBI by the scientific community. However, please understand that while we feel we have done a high quality job, this is not commercial software. The documentation lags considerably behind the software and we must make any changes required by our data production needs. Nontheless, many people have found it a useful and stable basis for a number of tools and applications. -- Tony Maher