DMRAID DOS format handler?

[Gaston, Jason D]

What is the DMRAID DOS format handler used for?

When I have an NTFS partition on a raid set, I get an additional level
of nesting displayed in device-mapper.  The NTFS partition shows up as a
linear raid level above my other raid level (mirror or stripe).  This
seemed strange to me, so I experimented with removing the DOS format
handler from DMRAID.  When I did this, I was no longer able to see the
NTFS partition sitting on top of my mirror.  Note:  I setup the NTFS
partition using Windows and the Intel Matrix Storage Manager.  I was
then able to make an ext3 file system on the mirror and write data to
it, in Linux.  I can now move the drive set back and forth with the
Windows system and see the NTFS and data on Windows and the ext3 and
different data in Linux.  How can both file systems exist on the raid
set?

Any info helping me to understand what is going on would be great!

Thanks,

Jason