I've bootstrapped uml host 'uml-test', which is downloaded from www.stearns.org/uml-root/, root_fs.fc-3-base.pristine.20050605.bz2. I have to use 'devfs=mount' to make it, otherwise, I'll get 'Unable to open initial console' error. Here is my set-up to build uml:

Host Kernel:
Skas: skas-2.6.11-v8.2
guest: uml-2.6.11-bs4
uml utils: 20040406
Distribution: Fedora Core 3

Uml kernel is built with DEVFS_FS enabled.

I'm using ska patched host kernel, uml kernel, root_fs, as shown above. I followed the root_fs notes as posted.  But
uml host won't boot WITHOUT adding 'devfs=mount'. I don't understand why. According to uml Documentation, DEVFS_FS is OBSELETE already. Can someone advise it? Thanks very much!