a general purpose library and file format for storing scientific data. It arranges data into datasets (multidimensional arrays) and groups (a structure for organizing objects). With extra software support like a viewer, etc...
a library for reading and editing the meta-data of several popular audio formats. Currently it supports both ID3v1 and ID3v2 for MP3 files, Ogg Vorbis comments and ID3 tags and Vorbis comments in FLAC files.
an open source viewer for Portable Document Format (PDF) files. he Xpdf project also includes a PDF text extractor, PDF-to-PostScript converter, and various other utilities.
an interface for array-oriented data access and a library that provides an implementation of the interface. The netCDF library also defines a machine-independent format for representing scientific data.