## 7 .MDZ files

This was written by Fabian Giesen, based on the original `.MDZ` description by Niklas Beisert.

### 7.1 What are `.MDZ` files?

`.MDZ` files are Module Description files (the MDZ is a short form of DIZ, which is in turn a short form of Description). The `.MDZ` format can, however, contain much more information than normal Module/Sound files, which normally only contain the song's title and sometimes a “song message”, which can be freely entered by the author. Things like the name of the author of a song, its playtime, a comment about it etc. which can be entered in OCP's Fileselector cannot be stored inside the module file, so they have to be stored somewhere else. Usually this is in the file `CPMODNFO.DAT`, which normally perfectly suits this task.

However, this format has some disadvantages. Imagine you give a module file to a friend. Simply copying your `CPMODNFO.DAT` together with the song on the disk is impractical, because this file overwrites your friend's `CPMODNFO.DAT` when he simply copies it. So he could take your description, write it down somewhere, and take it with him, but that is pretty uncomfortable.

That's why the `.MDZ` files were invented. `.MDZ` files contain the description of one or more module file(s), just like the `CPMODNFO.DAT`, but have attributes which make them interesting:

- `.MDZ` files are normal text files and therefore human readable
- The content of `.MDZ` files gets automatically inserted in the module description database `CPMODNFO.DAT` without need for user interaction
- `.MDZ` files can be exported from within the OCP fileselector with one keystroke (see section See Reference.)

### 7.2 Why should I use them?

(This section is intended for composers)

There are of course some good reasons for using them:

- Every OCP user sees your description automatically when he moves the cursor over the file
- The module type is also stored in `.MDZ` files, so you can explicitely force OCP to play your Module in Protracker (or FastTracker) mode, for example.
- Even if the user does not use OCP, he can still read your description, because `.MDZ` is a simple, human readable text format
- Creating `.MDZ` files is almost no extra work (you can create a complete `.MDZ` file from within OCP in less than one minute)

So, as you see, using `.MDZ` files has many advantages, but (almost) no disadvantages. It is surely worth trying.

### 7.3 The `.MDZ` file format

This is not documented here. If you want a complete description, wait for the soon to be released OCP Technical Reference Manual.