You could get that version compiling with some work, but I don't think it's a very good idea. You'll still need to write a lot of code to deal with things like process management, which a user level kernel can't actually help with. Having device files for the disks only gets you so far.
You'd be better off just porting fossil (venti is ported) to the current Plan 9 from User Space, which does not depend on a central user-space kernel. http://swtch.com/plan9port/ If you still want a user-space kernel, the drawterm code is essentially that, though it doesn't contain any provisions for running "system calls" on behalf of other processes. http://swtch.com/drawterm/ Russ
