I am purchasing either an MP-7 or a Yamaha RM1X and I have a couple of questions I use an alesis DATADISK can I store my sequences on it since the MP-7 doesn't have a disk drive? If not how do I save things to disk? Why should I buy an MP7 vs. the Yamaha? Can You mute tracks while they are playing? Will a new MP come with the newest O.S. or will I have to get it myself? Thanks Hopefully a future emu user (Very Very Very near future)