Bigger "dev_t"s

[Guy Harris]

(Continued from previous rock)  Some people at Sun have suggested the
same idea, with "specfs" becoming not just a class of vnodes but a
"real" mountable file system.  Bill Shannon suggested making "/dev/fd" a
file system; this has the advantages that

	1) you might not have to whack up the VFS kernel's "open" code
	   to pass an extra argument to device drivers (as in Arnold
	   Robbins' "/dev/fd" driver);

	2) you would't have to create or destroy entries based on the
	   maximum number of file descriptors per process supported by
	   your kernel.  (You could even get *truly* perverse and have it
	   look different in different processes, so that it reflects
	   the number of *open* file descriptors....)