Ironically, SEGA's GD-Rom technology was created as DVDs were not available for SEGA, and they wanted to create a disc that would be hard for pirates to copy and use.

"Sega intended to use the format to curb piracy common to standard compact discs and to offer increased storage capacity. It is similar to the standard CD-ROM except that the pits on the disc are packed more closely together, resulting in a higher storage capacity: around 1.2 gigabytes, which is almost double the storage capacity of a typical CD"

The Dreamcast is infamous for being the easiest console to pirate games on.
Contributed by retrolinkx