Packages are a zipped package of scripts and data files that can be added to the base J system, see howto.
FFTW is a Fast Fourier Transform for Windows.
Image 3 supports reading and writing image files.
JAR is a database for J words, data, test cases and general scripts.
LAPACK (Linear Algebra Package) is a set of routines for solving systems of simultaneous linear equations, least-squares solutions of linear systems of equations, eigenvalue problems, and singular value problems.
LBFGS is the Limited Memory Broyden-Fletcher-Goldfarb-Shanno (BFGS) method to solve an unconstrained nonlinear optimization problem. Also includes L-BFGS-B for solving large nonlinear optimization problems with simple bounds on the variables.
SFL is the Standard Function Library from iMatix, a portable function library for C/C++ programs.
Tara reads and writes Excel files.