(MESS) famicom: converted the disk system add-on to be a cart
in the softlist. The official syntax to launch disk games is now
  mess famicom -cart disksys -flop gamename
which corresponds to inserting the RAM expansion cart with
connected the disk drive into the cartslot and the desired disk
in the disk drive (exactly like you would have done with the
real thing). In this way, you cannot mount anymore both a cart and 
a disk in the Family Computer (as in a real unit). 
Users that cannot cope with this limitation and/or with the new 
syntax can still use the famitwin driver (which offers both cart and 
disk options) or the newly added driver fds which emulates a
famicom with the expansion always inserted: in both latter cases
the old syntax
  mess famitwin -flop gamename
will launch the game, as previously. [Fabio Priuli]

(MESS) famicom: fixed disk system IRQ latch clear in Kaettekita
Mario Bros. based on investigations by FHorse. [Fabio Priuli]


Out of whatsnew: For the moment I gave up the original plan to 
also modernize the floppy drive and the disk format. If anyone 
wants to look into these, be my guest :-)