So this might seem like a really newbish question but if I dedicate an external HD to TimeMachine, its just going to keep backing up into this HD until its full and then start deleting old backups?
Since Time Machine automatically backsup every hour, day, month (without the option to choose how often it backs up...correct me if I'm wrong)
So basically once you dedicate an external HD to TimeMachine its only use is for your backups on that specific mac hardware (unless you partition it of course).