iTunes Backup Method For Purchased Items
Since any items (music, TV shows, etc.) that you purchased from the iTunes Store are locked into your single iTunes account you have to keep them safe. So when you run out of on-disk space on your boot drive you’d want to copy the files before trashing them off you HD. Another HD is one solution but that disk could fail and get destroyed any second so that isn’t a good method. CD’s and DVD’s are the best option for this method. If you copy any items into a single playlist you can then burn that playlist to a disk. The files won’t lose their account encoding so they’ll only play on your mac but you do get the advantage of it being off-disk. When you next insert the disk you’ll see it show up in the “Devices” category of iTunes sources. Like any other optical media your disk will be able to both be imported and played straight off itself. Just note that DVD’s with only video aren’t encoded for DVD Player.app, just for iTunes.