HDF5 is a library and file format for storing scientific data. It was
designed to address some of the limitations of the HDF 4.x library and to
address current and anticipated requirements of modern systems and
applications. HDF5 includes the following improvements.

- A new file format designed to address some of the deficiencies of
HDF4.x, particularly the need to store larger files and more
objects per file.
- A simpler, more comprehensive data model that includes only two
basic structures: a multidimensional array of record structures,
and a grouping structure.
- A simpler, better-engineered library and API, with improved
support for parallel i/o, threads, and other requirements imposed
by modern systems and applications.