I just formatted a new DVD-R disc in the SuperDrive of my G4. What happened to the other .4GB?
When formatting a DVD-R disc for the SuperDrive, a portion of disc space must be reserved for storing HFS and ISO data structures, and for catalog information. Other types of disks also dedicate space to formatting. The amount of space used may seem more noticeable due to the larger capacity of DVD media. Thus the formatted capacity of a DVD disc is less than the unformatted 4.7GB capacity. After formatting your DVD disc, you should have just under 4.3GB of space available. You can verify capacity and available disc space by selecting the disc’s icon and choosing Show Info from the File menu.