  Preserving access to file content requires preserving not just bits but also
meaningful logical structures. The ongoing development of the Data Format
Description Language (DFDL) is a completely general standard that addresses
this need. The Defuddle parser is a generic parser that can use DFDL-style
format descriptions to extract logical structures from ASCII or binary files
written in those formats. DFDL and Defuddle provide a preservation capability
that has minimal format-specific software and cleanly separates issues related
to bits, formats, and logical content. Such a system has the potential to
greatly reduce overall system development and maintenance costs as well as the
per-file-format costs for long term preservation.
