I've read a lot of posts on how folks are using external SSD drives and placing them in Thunderbolt compatible enclosures for speeding up their MAC's performance. I have a 2011 iMac and want to boot off an external SSD via the Thunderbolt enclosures that I have read about. However, I am not sure what files I need to copy to the SSD so the iMAC boots up. I assume I need to move the O/S files but am not sure how this is done. I bought the iMAC at the Apple Store but no boot up disks came with this machine so if I need those, I don't have 'em. Also, how do I move apps? Is it just as simple as holding down the CMD key and dragging them to the SSD drive? Once I can boot off the external drive, I'd like to also move the apps off the hard drive too and keep the hard drive space more available. Thanks ahead of time.