Be careful how you count the gigs/megs/k. Some hard disk manufacturers like to say a megabyte is a million bytes. It allows them to say that their hard disks are bigger than they really are. A million bytes is actually significantly less than a real megabyte. A real megabyte is 1024 kilobytes, which, in turn, is 1024 bytes. So a real megabyte 1,048,576 bytes, and a real gigabyte (1024 megabytes) is 1,073,741,824 bytes. It's possible that there's a lot less overhead than you think, because you're getting your assumed totals from two different sources: one that calculates correctly, and one that assumes meg=million.