bincmp is intended as a cross-platform, tiny and fast binary comparer of two files. it is much faster than "fc /b", for example.
bincmp2 is more powerful, but currently windows-only.
small and fast library dealing with signal processing
Tiny-DSP library contains c sources of a fast, tiny, portable and generic FFT (Fast Fourier transform) and inverse FFT. Supported are all power of two sizes (like 2,4,8,16,32,...) for one and two dimensional floating point arrays.