external HDD usage

Using Disk Utility, create two partitions, one Mac OS Extended Journaled and the other Ex FAT, then format the Ex FAT partition in Windows as NTFS. You can change the size of each partition to your liking. This is what I did with my 4TB external hard drive.

 

I have no clue what magictheif is talking about. Perhaps he thinks you'll just split the drive in half and use half for windows, and half for OS X.


This is not what I do though. I have a 1TB external, and I have 2 partitions on it for different reasons. The first is a 200GB recovery partition that I back up my Time Machine too. Disabling local copies saves even more space on my internal SSD. The second partition i use is partitioned as exFAT. This is very similar to NTFS, and can be read and written to by both my MacBook Air and my Windows 7 Desktop. If you don't want to bother with External Time machine stuff you can always just do 1 large ExFat partition. I formatted both partitions with the Disk Utility on OSX, but I'm sure you can do it under windows also either with the included utilities or through a different third party program.