GD-ROM

GD-ROM (an abbreviation of "Gigabyte Disc Read-Only Memory") is a proprietary optical disc format originally used for the Dreamcast games console, as well as its arcade counterpart, the Sega NAOMI. Developed by Yamaha, 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.

Sega's use of the format instead of the new DVD-ROM technology supported by the PlayStation 2 has been considered a mistake that contributed to the Dreamcast's early demise. The DVD-ROM format allowed for larger storage capacity than the GD-ROM, as well as support for DVD Video playback that the Dreamcast lacked.

Despite the failure of the Dreamcast, Sega continued to use the GD-ROM format in arcades with the Sega NAOMI 2, Sega Chihiro and Triforce.