It would set up a few hidden programs the first time it's being executed, that would act as default filetypes (folder and plain text document). You could add more filetypes by putting more (hidden) programs on your calculator, like bitmap, compressed picture, movie, et cetera. And all files and directories are also little programs that you could put on your calculator, hidden if you want to. As you can see, it even supported directories in directories.
I never released it, because I had some very strange errors, and the external modules (read: filetypes) wouldn't be executed at progstart but at an unknown location, making developing modules quite tricky.
Anyway, from that experience I can advice you to stay away from directories on a calculator
It doesn't really add anything, and it's a pain in the ass because the OS doesn't really support it. If you'd - for instance - delete the folder Pictures with the Ti-OS, you'd have 6 files that claim to be located in a folder that does not exist, making it impossible to see or use those files, but they take up space nontheless... N00bs will never understand that kind of things with their brainwashed MS Windows XP logic...But something like a self-extracting ZIP-file would be a great idea, I think. And not so awfully difficult to make.
.
, but je parle français you know and english is not my native language. I'm still learning, like in BASIC (I still dont know how to use the IS and DS commands in TI-BASIC and I still havent figured out what is the difference between Ipart( and Int( 
