The ATLAS (Automatically Tuned Linear Algebra Software) project is an ongoing research effort focusing on applying empirical techniques in order to provide portable performance. It provides C and Fortran77 interfaces to a portably efficient BLAS implementation, as well as a few routines from LAPACK.
The mission of the Apache Portable Runtime (APR) project is to create and maintain software libraries that provide a predictable and consistent interface to underlying platform- specific implementations. The primary goal is to provide an API to which software developers may code and be assured of predictable if not identical behaviour regardless of the platform on which their software is built, relieving them of the need to code special-case conditions to work around or take advantage of platform-specific deficiencies or features.
The Extended Universal Resource Locator library provides a complete virtualization of file-like objects. How data is stored is completely transparent to the client, since the library is meant to replace java.io.File. It provides implementations for handling local files, Jar/Zip archives, and XML documents. (Implementations for CVS and FTP are available seperately.) Other storage providers can be written and plugged in. It also provides a merged filesystem implementation that allows multiple hierarchies to appear as one and to override each other in a controlled way. Other features include notification of changes to files, and support for attaching (dynamically updatable) actions to file objects.
FLTK (pronounced "fulltick") is a cross-platform C++ GUI toolkit for UNIX/Linux (X11), Microsoft Windows, and Mac OS X. It provides modern GUI functionality without the bloat, and supports 3D graphics via OpenGL and its built-in GLUT emulation. FLTK is designed to be small and modular enough to be statically linked, and also works fine as a shared library. It also includes an excellent UI builder called FLUID that can be used to create applications in minutes.
FXL Template an easy to use template engine offering all the basic features of a template system. It supports simple text/array assignments, blocks, and nested blocks. Well-used regular expressions and the simple template syntax are responsible for quick template processing. The template markup is quite easy to learn, even for those not into programming. A Memcache extension for high traffic pages is freely available.
Light-Weight Visual Components Library (LwVCL) is a powerful, small, fast, efficient, framework of visual components that provides a rich set of customizable, flexible user interface components. There are versions for J2SE/J2ME Personal Profile, J2ME MIDP, .NET, and SWT. This provides a unified GUI framework for different platforms that provides the same API, the same concepts, and the same look and feel.
PVM (Parallel Virtual Machine) is a portable message-passing programming system, designed to link separate host machines to form a ``virtual machine'' which is a single, manageable computing resource. The virtual machine can be composed of hosts of varying types, in physically remote locations. PVM applications can be composed of any number of separate processes, or components, written in a mixture of C, C++ and Fortran. The system is portable to a wide variety of architectures, including workstations, multiprocessors, supercomputers and PCs.