MSDOS file system as root

[vasant <v_kanchan%yahoo.com@localhost>]

Hi,

I have a custom init that I would like to run off a MSDOS file system.
Since I don't need any device special files or long names, I thought 
this should work. When I boot netbsd GENERIC on IBM Z50, it prints the following
message:
no file system for wd0 (dev 0x100)

What could be the problem ?. I can see that vfs_mountroot() scans through
all the file system.

Regards
Vasant