The first thing we need of a file is to check: Does it contain IFF data and, if so, does it contain the kind of data we're looking for? So we come to the notion of a "data section". A "data section" or IFF "FORM" is one self-contained "data object" that might be stored in a file by itself. It is one high level data object such as a picture or a sound effect, and generally contains a grouping of chunks. The IFF structure "FORM" makes it self-identifying. It could be a composite object like a musical score with nested musical instrument descriptions. Group FORM Composite FORMs Designing New Data Sections