In some email I received from Chris Torek, sie wrote:
> >Excuse my ignorance for a moment, but if you have a merged devsw entry,
> >how do you know which of the character/block devices you get by calling
> >open() if you're explicitly after one set of semantics and not the other?
> 
> Outside the kernel, in /dev, the file is still a "character" or
> "block" special file, and is opened as such.  This gives it a
> different kind of vnode with a different set of ops.  (Actually it
> just goes through spec_read and spec_write, which switch on vp->v_type
> again, which is silly, but never mind all that.)
[...]

Ah, I understand.  For some reason I was picturing merging the devsw's
as meaning we'd lose one of block/character devices (as is found on
Linux) but of course this is not necessarily the case.

Cheers,
Darren