I guess this is a combination hardware/software question also regarding Time Capsule and my Airport Extreme and my external hd so I put it here in the peripherals section. I picked up a usb hard drive kit from macsales a week or two back and hooked it up to my iMac without issue and am using it as my backup drive through Time Capsule. I just picked up an Airport Extreme from ebay which arrived yesterday and was set up in a matter of minutes. My plan was to always set up the drive as a network drive for back up for my iMac and my MBP. Is it too late to do that? Is it even possible to back up two different computers to the same external HD? Being new to this stuff, I'm just sort of trying to figure it all out and will likely replace the 500g drive I'm using with something bigger if I can backup both systems to the same drive. I don't work on anything major at these computers and am really just concerned about pictures and music primarily. More importantly I'd just like to have a working knowledge about the hardware and how it interacts with the software. Thanks in advance for all your help.