Calc is arbitrary precision arithmetic system that uses a C-like language. It's useful as a calculator, an algorithm prototype, and as a mathematical research tool. More importantly, calc provides a machine-independent means of computation. Calc comes with a rich set of builtin mathematical and programmatic functions.
CUPS is a standards-based printing system for Mac OS X and other Unix-like operating systems. It provides the System V and Berkeley command line interfaces, and uses the Internet Printing Protocol ("IPP") as the basis for managing print jobs and queues. The Line Printer Daemon (LPD) Server Message Block (SMB), and AppSocket (a.k.a. JetDirect) protocols are also supported with reduced functionality. CUPS adds network printer browsing and PostScript Printer Description ("PPD") based printing options to support real world printing.
Librep is a shared library implementing a Lisp dialect that is lightweight, reasonably fast, and highly extensible. It contains an interpreter, byte-code compiler, and virtual machine. Applications may use the interpreter as an extension language, or it may be used for standalone scripts. Rep was originally inspired by Emacs Lisp. However one of the main deficiencies of elisp--the reliance on dynamic scope--has been removed. Also, rep only has a single namespace for symbols.
The Tecla library provides programs with interactive command line editing facilities, similar to those of the Unix tcsh shell. It supports recall and editing of previously entered command lines, TAB completion of file names and application specific tokens, and in-line wild-card expansion of filenames. The optionally reentrant modules which perform TAB completion and wild-card expansion are also available separately for general use. The library is smaller, more modular, makes more efficient use of the heap, and has a less restrictive license than GNU readline.
Wine is an implementation of the Windows API on top of X and Unix. It does not require Microsoft Windows, but can use native Windows DLLs if they are available. It provides both a development toolkit for porting Windows source code to Unix as well as a program loader, allowing many unmodified Windows programs to run on x86-based Unixes.
DirectFB is a thin library that provides developers with hardware graphics acceleration, input device handling and abstraction, an integrated windowing system with support for translucent windows and multiple display layers on top of the Linux framebuffer device. It is a complete hardware abstraction layer with software fallbacks for every graphics operation that is not supported by the underlying hardware.
The Genetic Algorithm Utility Library (GAUL) is a programming library for evolutionary algorithms. Both steady-state and generation-based evolution is supported, together with the island model. GAUL supports the Darwinian, Lamarckian, and Baldwininan evolutionary schemes. Standard mutation, crossover, and selection operators are provided, while code hooks additionally allow custom operators. It provides data structures and functions for handling and manipulation of the data required for a genetic algorithm. Additional stochastic algorithms are provided for comparison to the genetic algorithms. Much of the functionality is also available through a simple S-Lang interface.