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GD-ROM

The GD-ROM is a proprietary optical disc format developed as a collaboration between Sega and Yamaha for the Dreamcast and other Sega systems.

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May 30, 2026
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GD-ROM
The underside of a GD-ROM disc
Media typeOptical disc
Capacity1 GB
Developed byYamaha
Usage

The GD-ROM (gigabyte disc read-only memory) is a proprietary optical disc format developed as a collaboration between Sega and Yamaha for the Dreamcast and other Sega systems.1

Specification

A double-density format based on the CD-ROM2 that could hold up to 1 GB, it consists of a single-density track near the disc's center surrounded by a double-density track comprising much of the disc's capacity.1 The GD-ROM was created in response to developers exceeding the typical 650 MB storage capacity of the CD-ROM; while DVD-ROM would have addressed this limitation, implementing its then-new technology would have made console production cost prohibitive.1 Along with the format's general novelty, the extra capacity also had the theoretical benefit of curbing video game piracy,34 a major concern of CD-based consoles that was validated by its rampancy on the PlayStation.56

Dreamcast console

The Dreamcast was considered by the video game industry as one of the most secure consoles on the market with its use of the GD-ROM,7 but this was nullified by a flaw in the Dreamcast's support for the MIL-CD format, a Mixed Mode CD first released on June 25, 1999, that incorporates interactive visual data similarly to CD+G.89ab A hacker group self-named Utopia released their exploit in June 2000, having discovered that they could replace the visual data with Dreamcast code, enabling games burned onto CD-Rs to run on the console without any modding;812 boot discs were initially used to facilitate this effort, but hackers subsequently discovered the ability to have burned games self-boot without the need for a boot disc.1213 The main protection was to scramble the EXE file on the disc. The Dreamcast console would unscramble it in memory if a GD-ROM was inserted; however when loading from an MIL-CD, the EXE file was loaded directly into memory, bypassing the copy protection 14. While copying Dreamcast games onto a CD-ROM sometimes required the removal of certain game features, this did not affect their playability; such games were typically distributed on file sharing networks such as Internet Relay Chat.1215 Sega initially responded by aggressively pursuing cease and desist orders against online marketplaces selling pirated games, announcing the effort a month after the exploit's release;7 the company eventually released a new revision of the Dreamcast hardware that removed MIL-CD support towards the end of 2000, closing the loophole.161718 Games released around that time also began to incorporate a more robust copy protection system to thwart illegitimate use.19

Before the Dreamcast was released, Sega "confirmed that Dreamcast owners will one day be able to upgrade the GD-ROM drive to DVD" as part of its general expansion system to keep it competitive against more powerful contemporaries.20 In June 1999, The Nihon Keizai Shimbun reported on the development of a DVD distribution system by Sega alongside Hitachi, Nippon Columbia, and an additional partner; one known planned use for it involved encrypted multi-title releases that were to be accessed via downloadable product keys.21 Despite displaying a Dreamcast DVD display unit at E3 2000,22 the plans for a DVD add-on or fully separate unit never materialized during the short production run of the Dreamcast, rendering it the only sixth generation console to not adopt the format.

Arcade systems

GD-ROM was also made available as an upgrade for the Dreamcast's arcade cousin, Sega NAOMI and the later Sega NAOMI 2, providing alternate media to its cartridge-based software.2324 It is also used as an option on both the Sega Chihiro and Triforce, respectively based on the Xbox and GameCube consoles.2526

The GD-ROM drive in the Dreamcast reads data in constant angular velocity (CAV) mode at up to 12× speed.1

GD-ROM drive as an option on Triforce source ↗
See also

See also

Notes

Notes

  1. The MIL-CD is only compatible with Japanese Dreamcast consoles due to regional lockout.10
  2. Unlike other mixed mode CDs, MIL-CD was capable of muting its data section from playback on typical CD players, preventing potential damage to connected speakers.910 Some GD-ROM titles include such a warning as an audio track.11
References

References

  1. Hagiwara, Shiro; Oliver, Ian (November–December 1999). "Sega Dreamcast: Creating a Unified Entertainment World". IEEE Micro. 19 (6): 29–35. doi:10.1109/40.809375.
  2. Kent, Steven (November 23, 1998). "Here comes Sega's Dreamcast". ZDNet. Archived from the original on October 8, 2024. Retrieved July 5, 2024.
  3. Ohbuchi, Yutaka (September 30, 1998). "New Look at Dreamcast". GameSpot. Archived from the original on December 4, 2024. Retrieved July 5, 2024.
  4. Robinson, John (September 9, 1999). "Sega unleashes a 128-bit monster on the gaming world". CNN. Archived from the original on November 8, 2012. Retrieved July 5, 2024.
  5. Scullion, Chris (30 November 2023). "The Games". The Dreamcast Encyclopedia: Every Game Released for the Sega Dreamcast. White Owl. p. 12. ISBN 978-1-5267-7224-4. Retrieved July 4, 2024 – via Google Books.
  6. Diver, Mike (April 18, 2024). "Dreamcast". THE CON50LE: 50 Years of Home Video Gaming. White Owl. p. 120. ISBN 978-1-3990-4050-1. Retrieved July 4, 2024 – via Google Books.
  7. "Sega Crushes Dreamcast Pirates". Wired. July 20, 2000. Archived from the original on June 16, 2024. Retrieved June 15, 2024.
  8. Kohler, Chris (October 2005). "Retro-Hack the Dreamcast". Retro Gaming Hacks. O'Reilly Media. ISBN 9780596009175. Archived from the original on 2024-06-15. Retrieved 2024-06-15.
  9. "First MIL CDs released in Japan". IGN. June 28, 1999. Archived from the original on June 15, 2024. Retrieved June 15, 2024.
  10. Gantayat, Anoop (June 7, 2000). "Soundtrack Review: Kitahe - Pure Songs and Pictures". IGN. Archived from the original on June 21, 2024. Retrieved June 17, 2024.
  11. Johnston, Chris (February 1999). "Hands On: Dreamcast". Electronic Gaming Monthly. No. 115. Ziff Davis. p. 26.
  12. Borland, John (June 30, 2000). "Hackers break Dreamcast safeguards, distribute games online". CNET. Archived from the original on October 29, 2014. Retrieved October 28, 2014.
  13. Carless 2004, p. 217
  14. "Dreamcast: GD-ROM vs Mil-CD".
  15. "Sega Shuts Down Computer Game Pirates". ABC News. July 21, 2000. Retrieved July 4, 2024.
  16. Carless 2004, p. 199
  17. Gantayat, Anoop (January 16, 2001). "Sega Kills MIL CD Format". IGN. Archived from the original on May 10, 2024. Retrieved June 10, 2024.
  18. Zackheim, Ben (January 27, 2005). "The Dreamcast never dies". Engadget. Archived from the original on June 15, 2024. Retrieved June 13, 2024.
  19. Bramwell, Tom (January 18, 2001). "Sega Fights Piracy". Eurogamer. Archived from the original on June 14, 2024. Retrieved June 15, 2024.
  20. "Dreamcast Expandability" (PDF). Electronic Gaming Monthly. Vol. 122. Ziff Davis. September 1999. p. 204. Archived (PDF) from the original on 2023-04-04. Retrieved 2020-06-18.
  21. "Sega to Co-Develop DVD Technology for Use with Dreamcast?". IGN. June 8, 1999. Retrieved June 11, 2024.
  22. Justice, Brandon (May 12, 2000). "E3 2000: First Look – Dreamcast DVD Player". IGN. Archived from the original on November 16, 2020. Retrieved November 14, 2020.
  23. Gantayat, Anoop (September 20, 2000). "JAMMA 2000: Naomi 2 Revealed". IGN. Archived from the original on June 15, 2024. Retrieved June 12, 2024.
  24. "SEGA Arcade Continues Its Dominance". IGN. February 9, 2001. Archived from the original on June 15, 2024. Retrieved June 12, 2024.
  25. Gantayat, Anoop (September 19, 2002). "JAMMA 2002: First Look at Chihiro". IGN. Archived from the original on June 15, 2024. Retrieved June 12, 2024.
  26. Gantayat, Anoop (February 21, 2002). "AOU2002: First Triforce Game Footage". IGN. Archived from the original on June 28, 2021. Retrieved June 12, 2024.
Bibliography

Bibliography

Carless, Simon (2004). Gaming Hacks. O'Reilly Media. ISBN 978-0-596-00714-0 – via Google Books.

External links