I am considering getting an external hard drive like this one, which you can plug into your wireless router and then computers on your network can back up to it. It says it supports both Mac and Windows, but I assume it comes formatted as NTFS. Would I need to re-partition the drive and create 2 partitions - one NTFS partition for my Windows computers, and one HFS+ partition for my Mac? Or does it somehow support both Mac and Windows computers out of the box?