Yes. There are two ways to do it. You can set up the B2 (and BB1) to be NAS (Network Attached Storage), which makes the hard disk on the B2 accessible to your tablet (or computer) on the network. Then you can copy or edit files just like you would on a disk that was physically attached to the computer.
The other way to do it is to Export the contents of the B2 to a USB disk. That command copies all the music to the disk, which is what you want to do the have a backup of all your music.