Nintendo Wii U on sale Nov. 18; what you need to know
No, the Wii U will format the disk to its own specifications once you connect the drive to the console. Your Wii U drive will apparently use a proprietary file system since the drive can't moonlight as a back-up storage drive for your PC. It's not clear if you can partition a drive and use just one side for the Wii U.
An external drive formatted for the Wii U is also tied to one specific unit. That means you can't download a new game for the Wii U at home, store it to your external HDD, and then hook your HDD up to a friend's Wii U console later to play your new game.
Does the Wii U support multiple external hard drives
You can format multiple hard drives to work with the Wii U, but the console can currently handle just one external HDD at a time. Nintendo says it plans to roll out at a later date the ability to connect multiple external storage units on one Wii U.
What other features are included in the Wii U