Simple Data format
This page describes one of several known SDF file formats, and at least two formats called simple data format. This is the Simple Data Format by George H Fisher, Space Sciences Lab, UC Berkeley. It provides a simple "way of reading and writing output data from numerical simulations that preserves full precision, is simple, easy to use, that supports large (> 2GB) files, works in C, Fortran77, Fortran95, and IDL/GDL, compiles out of the box in the most common operating systems (Linux, Windows, OS X, Solaris), and is not affected by platform endian-ness".
The format is described in the Manifesto. That document and http://swan.gsfc.nasa.gov/RoR_WWW/workshops/2007/presentations/day4/fisher-sdf-ccmc-2007.pdf seem to provide its main specification.
Version 0.74 (the latest known) dates from September 2007.
There is a Wikipedia page about this version of the Simple Data Format but it has very little information.
SDF has been tested on many different platforms including Linux and other UNIX variants, Windows and MacOSX. It can be used from C, different versions of FORTAN, and IDL. The software can be downloaded as a tarball from http://solarmuri.ssl.berkeley.edu/~fisher/public/software/SDF.
Bytes 0-10 of a SDF file contain the string "SDF Format" including null terminator.
The file extension is .sdf and the MIME Type is not known.
As noted, the format is described inthe Manifesto at http://solarmuri.ssl.berkeley.edu/~fisher/public/software/SDF/SDF_MANIFESTO.txt.