I-files are an intermediate data format between stage2 data files and graphical music notation; they are a parametric description of the graphical layout of printable music notation. I-files come in two varieties: "linear" i-files which describe the graphical notation for a single part in each file on a single long (linear) system with no line or page breaks. "Linear" i-files are used to produce "Page-specific" i-files (either for parts, or for scores). Each page-specific i-file contains a description of the graphical music notation layout for a single printable page of the score/part. Here is the formal description of the i-file format displayed in a fixed-width font and color markers as it would be displayed within the dmuse IDE.
The i-files are typically produced by the autoset program which takes stage2 files as input. The files typically are stored in a standard sub-directory called outputs off of the main working director for a work. Within the outputs directory there is a project directory for a particular typesetting project, such as score or parts. With one of these sub-directories, i-files will be stored within a directory called i-files and then within a directory which matches the movement directory of the original stage2 sub-directory structure.
Here are some example i-files for Corelli's Op. 1, No. 12 sonata. The first column gives the filename and directory location within the main work directory (op1n12) if the sub-directory for the typesetting project is called score.
|op1n12/outputs/score/i-files/01/01||Violino 1 i-file|
|op1n12/outputs/score/i-files/01/02||Violino 2 i-file|
|op1n12/outputs/score/i-files/01/03||Violone e Organo i-file|