<file format> (IFF) A generic file format used on the Amiga, designed by Electronic Arts. IFF was chunk-based and hierarchical so files could include other files and was easily extensible and was all round a good idea.
File types are generally known by their 4 character designation so the main image type is ILBM, audio is either AIFF or 8SVX, animations are ANIM etc.
The choice of extension is, I guess, rather arbitrary as the information is in the file itself (as it should be).
Microsoft WAV and AVI are all based around an almost identical scheme to IFF called RIFF.
(21 Apr 1995)