Hi Sergey Nameless,

Your undo reasoning is sound, but another way to simplify file system development is to use a virtual drive on a real system. There is a great one here:

hxxp://www.insidewindows.info/filedisk.zip

This allows you to create a sparse file which is mounted like a real hard drive. As the file is sparse, it will be only as big as the data you put on it. You can keep multiple copies, old problem setups and even do diffs via sourcesafe or another version control system.

hxxp://www.insidewindows.info/ also has a number of cool source file systems and recognizers based on the NTIFS.h (also on that site). If you're in a hurry you might also want to check out
hxxp://www.exetools.com/forum/showthread.php?t=4617

Enjoy, WFCC