From HDF's manpage: hdf - Hierarchical Data Format library Description: HDF is a multi-object file format that facilitates the transfer of various types of scientific data between machines and operating systems. Machines currently sup- ported include the Cray, Convex, HP, Vax, Sun, IBM RS/6000, Silicon Graphics, Macintosh, and IBM PC comput- ers. HDF allows self-definitions of data content and easy extensibility for future enhancements or compatibility with other standard formats. HDF includes Fortran and C calling interfaces,and utilities to prepare raw image of data files or for use with other NCSA software. The HDF library contains interfaces for storing and retrieving compressed or uncompressed 8-bit and 24-bit raster images with palettes, n-Dimensional scientific datasets and binary tables. An interface is also included that allows arbitray grouping of other HDF objects.