I've never used Time Machine but have just got a 3TB drive mainly to accommodate my DVD collection (400-500 DVDs) which I plan to rip and encode for Apple TV. I thought I might partition the drive and use it to back up my MacBook Pro via Time Machine. If I set up a 1TB partition for Time Machine, am I right in thinking it should be big enough to keep two backups at a time of my 500GB MacBook Pro drive? And can I set it up to then back up say, once a week? Sorry if this seems like something obvious. Still trying to get my head round how Time Machine works.