File format reference
- Library of Congress Digital Formats Website: Provides information about digital content formats, including recommendations for preservation formats.
- PRONOM: Supplies technical information about the structure of those file formats, and the software products which support them.
- MIME Media Types
- Freebase: File Format
- Wikipedia: List of file formats
- GDFR, superceded by UDFR
- Note that some Operating Systems and other pieces of software (like web servers) include 'MIME Map' files, that map between file extensions and MIME Types/
- And of course Operating Systems tend to use file extension as the authoritative format identifier. Apple have a powerful hierarchical identifier scheme.
- A number of sites allow formats to be looked-up by extensions, e.g. http://www.wotsit.org/ or http://www.fileinfo.com/