GD-ROM Dumping Guide
From Redump Wiki
WORK IN PROGRESS
This is a step-by-step guide designed to be easy to follow so that you can make reproducible, good dumps of your GDs to the Redump standard.
What are GDs?
GDs—or Gigadiscs—are the type of optical media used by the Sega Dreamcast as well as the Sega NAOMI, Sega NAOMI 2, Sega Chihiro and Triforce arcade systems. It is special compared to its relative—the CD—in that it contains both a low density (LD) and a high density (HD) area. To get a good dump, you need to extract them both from the disc.
How do I know if I have a GD?
If you have any of the officially released discs for the Dreamcast or any of the above mentioned arcade systems, you are pretty much guaranteed to have a GD. The Dreamcast did however support loading of MIL-CDs, which lead to a number of unlicensed software being pressed on regular CDs. Check for the GD-ROM mark on the disc or check the reflective side of the disc for a visible LD–HD divide if you are unsure.
