I have an ext. hdd that I was using for my PC some years ago that I recently dug back out. It was formatted NTFS. So after doing some reading on this topic, I know I can on read from this hdd and I'll have to reformat it to be able to read/write. So using the Disk Utility I guess I'm suppose to reformatted as Mac OS Extended (journaled) because it's most common. Can I partition the drive and reformatted only a portion of it?