A long time ago, in a galaxy far, far away, floppy disks were the best thing that anyone had for removable data storage. Back then, 1.44 MB was sometimes enough to save a whole program. But if not, the only other option was to create a multi-disk archive file. All it means is that you have one zip file stored over multiple disks, and the archive includes information on the order in which they are to be unzipped.