Thanks a lot, I have't noticed QAbstractFileEngine class.

As I've understood I should implement my own QAbstractFileEngine and QAbstractFileEngineHandler classes. And one question.

Documentation:
When you open a file, Qt chooses a suitable file engine by passing the file name from QFile or QDir through an internal list of registered file engine handlers.
I need access to whole file system, so I should use my own file name format, like fat:c:\windows or ntfs:d:\folder? Or something else? So, how can I say that some filesystem path must be processed using my file engine?