GDIS is a visualization program for small molecules, crystals, and solution cells. It is in development, but is nonetheless fairly functional. It has support for BIOSYM, XYZ, XTL, MARVIN, and GULP files, and assorted tools for visualization, animation, and model creation. Rendering of molecules and energy minimization are also possible via Povray and GULP.
gEDA is a suite of electronic design automation (EDA) tools. Currently, the project offers a mature suite of free software applications for electronics design, including schematic capture, attribute management, bill of materials (BOM) generation, netlisting into over 20 netlist formats, analog and digital simulation, and printed circuit board (PCB) layout.
Genius is an arbitrary precision integer and multiple precision floating point calculator. It includes its own programming language similar in some aspects to C, bc, or Pascal. It can deal with rational numbers and complex numbers. It has matrix support as well. It uses the gmp library so it is very fast for calculations of large numbers. It has a command line and a GNOME interface. The GNOME interface supports plotting functions and 3D surfaces.
Genpak is a small set of utilities designated to process DNA, RNA, and protein sequences in a very Un*x-like manner. This way, Genpak programs can be combined using pipes and redirections, as well as easily incorporated into CGI scripts. The utilities include a program for calculating GC content, Tm, translating DNA/RNA sequences into protein sequences, quick sequence retrieval, random sequence generation, and finding promoter sequences using a Hertz matrix.
GEODAS (GEOphysical DAata System) is an interactive database management system developed by the National Geophysical Data Center (NGDC) for use in the assimilation, storage and retrieval of geophysical data. The GEODAS software is presently being used with several types of data: Marine Trackline Geophysical Data, Hydrographic (bathymetric sounding) Survey Data, Aeromagnetic Survey Data, and Coastal Relief Model (bathymetric/topographic) grids. Searches by geographic area, year of survey, source, platform/project, survey identifier, or data type are available.
Ghemical is a molecular modelling software package with some nice 3D visualization tools. It supports methods based on both molecular mechanics and quantum mechanics (using MOPAC7, and MPQC for QM). The geometry optimization (for MM and QM) and molecular dynamics (for MM) algorithms are included. Ghemical is written in C++, and hopefully offers a good framework for a generic freeware molecular modelling tool.