View source for GD-ROM

{{short description|Proprietary optical disc format used in the Dreamcast and other Sega systems}}
{{Infobox storage medium
| name          = GD-ROM
| logo          = [[File:GD-ROM logo.png|frameless|130px|class=skin-invert]]
| logo_size     =
| image         = Gdrom.jpg
| caption       = The underside of a GD-ROM disc
| type          = [[Optical disc]]
| encoding      = 
| capacity      = 1 [[gigabyte|GB]]
| blocksize     = 
| read          = 
| write         = 
| standard      = 
| owner         = [[Yamaha Corporation|Yamaha]]
| use           = {{Unbulleted list
   | [[Dreamcast]]
   | [[Sega Chihiro]]
   | [[Sega NAOMI]]
   | [[Triforce (arcade system board)|Triforce]]
   }}
| dimensions    = 
| weight        = 
| extended from = 
| extended to   = 
}}
{{Optical disc authoring}}
The '''GD-ROM''' ([[gigabyte]] disc [[read-only memory]]) is a proprietary [[optical disc]] format developed as a collaboration between [[Sega]] and [[Yamaha Corporation|Yamaha]] for the [[Dreamcast]] and other Sega systems.<ref name="Unified">{{cite journal |last1=Hagiwara |first1=Shiro |last2=Oliver |first2=Ian |date=November–December 1999 |title=Sega Dreamcast: Creating a Unified Entertainment World |journal=[[IEEE Micro]] |volume=19 |pages=29–35 |doi=10.1109/40.809375 |number=6}}</ref>

== Specification ==
A double-density format based on the [[CD-ROM]]<ref>{{cite news |last1=Kent |first1=Steven |title=Here comes Sega's Dreamcast |url=https://www.zdnet.com/article/here-comes-segas-dreamcast/ |access-date=July 5, 2024 |work=[[ZDNet]] |date=November 23, 1998 |language=en}}</ref> that could hold up to {{val|1|ul=GB}}, it consists of a single-density [[track (optical disc)|track]] near the disc's center surrounded by a double-density track comprising much of the disc's capacity.<ref name="Unified" /> The GD-ROM was created in response to developers exceeding the typical {{val|650|ul=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.<ref name="Unified" /> Along with the format's general novelty, the extra capacity also had the theoretical benefit of curbing [[video game piracy]],<ref>{{cite news |last1=Ohbuchi |first1=Yutaka |title=New Look at Dreamcast |url=https://www.gamespot.com/articles/new-look-at-dreamcast/1100-2464977/ |access-date=July 5, 2024 |work=[[GameSpot]] |date=September 30, 1998}}</ref><ref>{{cite news |last1=Robinson |first1=John |title=Sega unleashes a 128-bit monster on the gaming world |url=http://www.cnn.com/TECH/computing/9909/09/dreamcast/ |access-date=July 5, 2024 |work=[[CNN]] |date=September 9, 1999}}</ref> a major concern of [[CD]]-based consoles that was validated by its rampancy on the [[PlayStation (console)|PlayStation]].<ref>{{cite book |last1=Scullion |first1=Chris |title=The Dreamcast Encyclopedia: Every Game Released for the Sega Dreamcast |date=30 November 2023 |publisher=[[White Owl (books)|White Owl]] |isbn=978-1-5267-7224-4 |page=12 |chapter-url=https://books.google.com/books?id=vFXHEAAAQBAJ&pg=PA12 |access-date=July 4, 2024 |language=en |chapter=The Games |via=[[Google Books]]}}</ref><ref>{{cite book |last1=Diver |first1=Mike |title=THE CON50LE: 50 Years of Home Video Gaming |date=April 18, 2024 |publisher=[[White Owl (books)|White Owl]] |isbn=978-1-3990-4050-1 |page=120 |chapter-url=https://books.google.com/books?id=byrqEAAAQBAJ&pg=PA120 |access-date=July 4, 2024 |language=en |chapter=Dreamcast |via=[[Google Books]]}}</ref>

== 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,<ref name="Wired">{{cite magazine |title=Sega Crushes Dreamcast Pirates |url=https://www.wired.com/2000/07/sega-crushes-dreamcast-pirates/ |access-date=June 15, 2024 |magazine=[[Wired (magazine)|Wired]] |date=July 20, 2000}}</ref> 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]].<ref name="Kohler">{{cite book |last1=Kohler |first1=Chris |chapter=Retro-Hack the Dreamcast |chapter-url=https://www.oreilly.com/library/view/retro-gaming-hacks/0596009178/ch04s20.html |title=Retro Gaming Hacks |date=October 2005 |publisher=[[O'Reilly Media]] |isbn=9780596009175 |language=en}}</ref><ref name="MIL-CD release - IGN">{{cite news |title=First MIL CDs released in Japan |url=https://www.ign.com/articles/1999/06/29/first-mil-cds-released-in-japan |access-date=June 15, 2024 |work=[[IGN]] |date=June 28, 1999 |language=en}}</ref>{{efn|The MIL-CD is only compatible with Japanese Dreamcast consoles due to [[regional lockout]].<ref name="Kitahe - IGN">{{cite web |last1=Gantayat |first1=Anoop |title=Soundtrack Review: Kitahe - Pure Songs and Pictures |url=https://www.ign.com/articles/2000/06/08/soundtrack-review-kitahe-pure-songs-and-pictures |website=IGN |access-date=June 17, 2024 |language=en |date=June 7, 2000}}</ref>}}{{efn|Unlike other mixed mode CDs, MIL-CD was capable of muting its data section from playback on typical [[CD player]]s, preventing potential damage to connected speakers.<ref name="MIL-CD release - IGN" /><ref name="Kitahe - IGN" /> Some GD-ROM titles include such a warning as an audio track.<ref name="EGM115">{{cite magazine |title=Hands On: Dreamcast |last=Johnston |first=Chris |date=February 1999 |magazine=[[Electronic Gaming Monthly]] |publisher=[[Ziff Davis]] |issue=115 |page=26}}</ref>}} 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-R]]s to run on the console without any [[modding]];<ref name="Kohler" /><ref name="Hackers">{{cite news |last=Borland |first=John |date=June 30, 2000 |title=Hackers break Dreamcast safeguards, distribute games online |url=http://news.cnet.com/2100-1023-242686.html |archive-url=https://web.archive.org/web/20141029093337/http://news.cnet.com/2100-1023-242686.html |archive-date=October 29, 2014 |access-date=October 28, 2014 |work=[[CNET]]}}</ref> 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.<ref name="Hackers" /><ref>{{Harvnb|Carless|2004|page=217}}</ref> 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]].<ref name="Hackers" /><ref>{{cite news |title=Sega Shuts Down Computer Game Pirates |url=https://abcnews.go.com/Technology/story?id=119647 |access-date=July 4, 2024 |work=[[ABC News (United States)|ABC News]] |date=July 21, 2000 |language=en}}</ref> 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;<ref name="Wired" /> the company eventually released a new revision of the Dreamcast hardware that removed MIL-CD support towards the end of 2000, closing the loophole.<ref>{{Harvnb|Carless|2004|page=199}}</ref><ref>{{cite news |last1=Gantayat |first1=Anoop |title=Sega Kills MIL CD Format |url=https://www.ign.com/articles/2001/01/17/sega-kills-mil-cd-format |access-date=June 10, 2024 |work=IGN |date=January 16, 2001 |language=en}}</ref><ref>{{cite news |last1=Zackheim |first1=Ben |title=The Dreamcast never dies |url=https://www.engadget.com/2005-01-27-the-dreamcast-never-dies.html |access-date=June 13, 2024 |work=[[Engadget]] |date=January 27, 2005}}</ref> Games released around that time also began to incorporate a more robust copy protection system to thwart illegitimate use.<ref>{{cite news |last1=Bramwell |first1=Tom |title=Sega Fights Piracy |url=https://www.eurogamer.net/article-29995 |access-date=June 15, 2024 |work=[[Eurogamer]] |date=January 18, 2001 |language=en}}</ref>

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.<ref>{{cite magazine |url=https://retrocdn.net/images/2/26/EGM_US_122.pdf |title=Dreamcast Expandability |magazine=Electronic Gaming Monthly |publisher=Ziff Davis |volume=122 |date=September 1999 |page=204}}</ref> 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 key]]s.<ref>{{cite news |title=Sega to Co-Develop DVD Technology for Use with Dreamcast? |url=https://www.ign.com/articles/1999/06/09/sega-to-co-develop-dvd-technology-for-use-with-dreamcast |access-date=June 11, 2024 |work=IGN |date=June 8, 1999 |language=en}}</ref> Despite displaying a Dreamcast DVD display unit at E3 2000,<ref>{{Cite web|last=Justice|first=Brandon|url=https://www.ign.com/articles/2000/05/12/e3-2000-first-look-a-dreamcast-dvd-player?amp=1|title=E3 2000: First Look – Dreamcast DVD Player|work=IGN|date=May 12, 2000}}</ref> 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.<ref>{{cite news |last1=Gantayat |first1=Anoop |title=JAMMA 2000: Naomi 2 Revealed |url=https://www.ign.com/articles/2000/09/21/jamma-2000-naomi-2-revealed |access-date=June 12, 2024 |work=IGN |date=September 20, 2000 |language=en}}</ref><ref>{{cite news |title=SEGA Arcade Continues Its Dominance |url=https://www.ign.com/articles/2001/02/10/sega-arcade-continues-its-dominance |access-date=June 12, 2024 |work=IGN |date=February 9, 2001 |language=en}}</ref> It is also used as an option on both the [[Sega Chihiro]] and [[Triforce (arcade system board)|Triforce]], respectively based on the [[Xbox (console)|Xbox]] and [[GameCube]] consoles.<ref>{{cite news |last1=Gantayat |first1=Anoop |title=JAMMA 2002: First Look at Chihiro |url=https://www.ign.com/articles/2002/09/19/jamma-2002-first-look-at-chihiro |access-date=June 12, 2024 |work=IGN |date=September 19, 2002 |language=en}}</ref><ref>{{cite news |last1=Gantayat |first1=Anoop |title=AOU2002: First Triforce Game Footage |url=https://www.ign.com/articles/2002/02/21/aou2002-first-triforce-game-footage |access-date=June 12, 2024 |work=IGN |date=February 21, 2002 |language=en}}</ref>

The GD-ROM drive in the Dreamcast reads data in [[constant angular velocity]] (CAV) mode at up to 12× speed.<ref name="Unified" />

[[File:Triforce hardware (2).png|thumb| GD-ROM drive as an option on Triforce]]

== See also ==
*[[Nintendo optical discs]]
*[[Double-density compact disc]]
*[[MIL-CD]]
*[[Universal Media Disc]]

== Notes ==
{{notelist}}

== References ==
{{reflist}}

== Bibliography ==
{{cite book |last1=Carless |first1=Simon |author-link=Simon Carless |title=Gaming Hacks |date=2004 |publisher=[[O'Reilly Media]] |isbn=978-0-596-00714-0 |url=https://books.google.com/books?id=zrqz84QUuSEC |language=en |via=[[Google Books]]}}

== External links ==
* [https://web.archive.org/web/20080218151806/http://mc.pp.se/dc/gdrom.html Sega's GD-ROM Presentation]
* [https://segaretro.org/images/5/5d/Gdfm_k214e.pdf GD-ROM Format Basic Specification Ver. 2.14]

{{Optical storage media}}
{{Sega|Dreamcast}}
{{Dreamcast}}

{{DEFAULTSORT:Gd-Rom}}
[[Category:Computer-related introductions in 1998]]
[[Category:120 mm discs]]
[[Category:Dreamcast]]
[[Category:Sega hardware]]
[[Category:Video game distribution]]