Sustainability of Digital Formats
Planning for Library of Congress Collections
Sustainability of Digital Formats
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| Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact | |
| Full name | HDF5, Hierarchical Data Format, Version 5 |
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| Description | HDF5 is a general purpose library and file format for storing scientific data. HDF5 can store two primary types of objects: datasets and groups. A dataset is essentially a multidimensional array of data elements, and a group is a structure for organizing objects in an HDF5 file. Using these two basic objects, one can create and store almost any kind of scientific data structure, such as images, arrays of vectors, and structured and unstructured grids. You can also mix and match them in HDF5 files according to your needs. HDF5 does not limit the size of files or the size or number of objects in a file. HDF5 does not require all data to be written at once; datasets may be extended later if necessary.
HDF5 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. |
| Production phase | Generally used for middle- and final-state archiving. |
| Relationship to other formats | |
| Has subtype | Includes version 5.0 and later releases not documented separately here. |
| Affinity to | HDF4, Hierarchical Data Format, Version 4 |
| LC experience or existing holdings | None |
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| LC preference | None |
| Disclosure |
The HDF software was developed and supported by NCSA and is freely available. In July 2005, NCSA announced that the "Hierarchical Data Format group is spinning off from the National Center for Supercomputing Applications (NCSA) as a non-profit corporation supporting open source software and non-proprietary data formats."
Source code for the HDF libraries is available in Fortran and C. Some tools are available as Java source. |
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| Documentation | http://hdfgroup.org/HDF5/doc/ |
| Adoption | The press release for the spin-off of the HDF Gropup states, "These freely available tools are used by an estimated 2 million users in fields from environmental science to the aerospace industry and by entities including the U.S. Department of Energy, NASA, and Boeing. It is used world-wide in many fields, including Environmental Science, Neutron Scattering, Non-Destructive Testing, and Aerospace, to name a few. Scientific projects that use HDF include NASA's HDF-EOS project, and the DOE's Advanced Simulation and Computing Program." NASA's Earth Observing System, the primary data repository for understanding global climate change, uses HDF. |
| Licensing and patents | None. |
| Transparency | TBD. |
| Self-documentation | An HDF structure is self-describing, allowing an application to interpret the structure and contents of a file without any outside information. Supports user-defined attributes and annotations. |
| External dependencies | None. |
| Technical protection considerations | None. |
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| Normal rendering. | Normal rendering for datasets not established yet. |
| Tag | Value | Note |
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| Filename extension | hdf |
| General | There are two HDF formats, HDF (4.x and previous releases) and HDF5. These formats are completely different and NOT compatible. New projects are encouraged to use HDF5. |
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| History | The HDF Group was spun off from the National Center of Supercomputing Applications (NCSA) as a non-profit corporation in July 2005. The new corporation, "The HDF Group" (THG), will continue to support open source software and non-proprietary data formats.
A new web site has been set up for THG at: http://www.hdfgroup.org/. |
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