From Fedora Project Wiki
CD sizes are measured in MiB (so the size of a "700 MB" CD is actually closer to 700 MiB - see http://en.wikipedia.org/wiki/CD-ROM#Capacity), but DVDs are measured in GB (so a "4.7 GB" DVD is almost exactly 4,700,000,000 bytes - see http://en.wikipedia.org/wiki/DVD#DVD_capacity). I'm not sure about the minimum size - is it 2 MiB, or 2 MB? -Robatino
Edit: I've been told there's no specific minimum size, so it doesn't really matter. -Robatino