Modify file structure so that a file can be composed of multiple subfiles, or files embedded in a file. In normal usage a subfile would appear to be inserted directly into the parent file, but alternative interfacing would allow a subfile to be opened independently. Could be viewed as an index into the parent file or as a dynamic concatenation of several files. Allows a dynamic insert of data - data literally inserted into a file by appending it to a subfile.

Steps: 1) fixed position layout/distribution changes 2) dynamic positions 3) subfile indexing 4) enabling interfaces