tmpfs now operational in development branch

[Matthew Dillon]

    We now have a very nice port by Naoya Sugioka of TMPFS from NetBSD
    in our main development branch.  It is brand new and still considered
    experimental but should be reasonably stable.

    TMPFS is a better alternative to MFS and MD for temporary filesystems.
    It doesn't have the data duplication issue that MFS has and its data
    is swap-backed using a very nice algorithm that only pages data to swap
    when the system is under real memory pressure (and not due to buffer
    cache flushes, fsyncs, or anything else).

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>