A little quote from a mail message that was highlighed to me

Particularly since building it into the OS or file system gets more end-programmers 
and end-users to use it (unlike libferris 
http://witme.sourceforge.net/libferris.web/index.html).

which can be found at: The reiserfs mailinglist msg link

I find it amusing that Alexander G. M. Smith doesn't consider LD_PRELOAD, NFS/CODA servers or indeed microkernel designs. Its not like libferris is by any means a statically cast code block that will never change.