I am running a mac os x/xp dual boot system. I have a very large external drive that I want to use as as backup for each system. I have formatted one partition (120GB) as NTFS using xp. I am using this partition to backup my xp system. I want use mac os x to format the rest of the unallocated space (110GB) in a mac format so that I can backup my mac system to this new partition. Using the mac disk utility I cannot figure out how to format the unallocated space without deleting all the information on my NTFS partion. I am a lifelong PC user and am new to this mac stuff. If anyone can tell me how to do this, that would be great!