In the Windows world I can create a file system filter (upper or lower) in order to hook my driver to action when a file is changed (for example auditing or creating virtual drives).
Do you know which is the similar model in a Mac? the I/O Kit talks about driver development but does not specify the storage model or file system. Is there another kit?
Looks like there is a private API that spotlight uses, some source available here:
http://osxbook.com/software/fslogger/
If you want to create your own filesystem (like what a virtual drive would be), use MacFuse