http://en.wikipedia.org/wiki/COFF
... you mean "Common Object File Format" format used in MS "Portable Executable" format?
djgpp ha a coff spec
http://delorie.com/djgpp/doc/coff/
Though primarily an object file format, it used to be used as a binary as well.
However, the format is limited and very old. These days, we use the "Executable and Linkable Format". You can convert COFF to ELF with the objcopy tool.
