GD-ROM (an abbreviation of "
Gigabyte
The gigabyte () is a multiple of the unit byte for digital information. The prefix ''giga'' means 109 in the International System of Units (SI). Therefore, one gigabyte is one billion bytes. The unit symbol for the gigabyte is GB.
This defini ...
Disc
Read-Only Memory
Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing sof ...
") is a proprietary
optical disc
In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc that encodes binary data (bits) in the form of pits and lands on a special material, often aluminum, on one of its flat surfaces. ...
format originally used for the
Dreamcast
The is a home video game console released by Sega on November 27, 1998, in Japan; September 9, 1999, in North America; and October 14, 1999, in Europe. It was the first sixth-generation video game console, preceding Sony's PlayStation 2, N ...
video game console, as well as its arcade counterpart, the
Sega NAOMI
Sega is a video game developer, publisher, and hardware development company headquartered in Tokyo, Japan, with multiple offices around the world. The company's involvement in the arcade game industry began as a Japan-based distributor of coin-o ...
and select Triforce arcade board titles. It was developed by
Yamaha Yamaha may refer to:
* Yamaha Corporation, a Japanese company with a wide range of products and services, established in 1887. The company is the largest shareholder of Yamaha Motor Company (below).
** Yamaha Music Foundation, an organization estab ...
to curb piracy common to standard
CDs and to offer increased storage capacity without the expense of the fledgling
DVD-ROM
The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any ki ...
. It is similar to the standard
CD-ROM
A CD-ROM (, compact disc read-only memory) is a type of read-only memory consisting of a pre-pressed optical compact disc that contains data. Computers can read—but not write or erase—CD-ROMs. Some CDs, called enhanced CDs, hold both comput ...
except that the pits on the disc are packed more closely together, resulting in a higher storage capacity of 1
gigabyte
The gigabyte () is a multiple of the unit byte for digital information. The prefix ''giga'' means 109 in the International System of Units (SI). Therefore, one gigabyte is one billion bytes. The unit symbol for the gigabyte is GB.
This defini ...
,
a 42% increase over a conventional CD's capacity of 700 megabytes.
The Dreamcast ended up being the only sixth-generation console with a disc based on CD technology rather than DVD technology; even the
Nintendo
is a Japanese Multinational corporation, multinational video game company headquartered in Kyoto, Japan. It develops video games and video game consoles.
Nintendo was founded in 1889 as by craftsman Fusajiro Yamauchi and originally produce ...
GameCube
The is a home video game console developed and released by Nintendo in Japan on September 14, 2001, in North America on November 18, 2001, and in PAL territories in 2002. It is the successor to the Nintendo 64 (1996), and predecessor of the Wii ...
's smaller 8 cm discs held 50% more data due to being based on DVD technology. In addition, GD-ROM proved to be an ineffective anti-piracy measure when it was discovered the Dreamcast's forgotten
MIL-CD
MIL-CD or Music Interactive Live CD is a compact disc format created by the video game company Sega in 1998. The main purpose of MIL-CD was to add multimedia functions to music CDs, for use in Sega's Dreamcast video game console. For example, MIL- ...
functionality could be exploited to boot games burned to CD albeit with some content removed.
After the discontinuation of the Dreamcast worldwide on March 31, 2001, Sega continued to use the GD-ROM format in arcades with the
Sega NAOMI 2
Sega is a video game developer, publisher, and hardware development company headquartered in Tokyo, Japan, with multiple offices around the world. The company's involvement in the arcade game industry began as a Japan-based distributor of coin-o ...
,
Triforce
The is a fictional artifact and icon of Nintendo's ''The Legend of Zelda'' series of video games. It first appeared in the original 1986 action-adventure game ''The Legend of Zelda'' and is a focus of subsequent games in the series, including ...
and
Sega Chihiro
Sega is a video game developer, publisher, and hardware development company headquartered in Tokyo, Japan, with multiple offices around the world. The company's involvement in the arcade game industry began as a Japan-based distributor of coi ...
. With the release of the
Sega Lindbergh
Sega is a video game developer, publisher, and hardware development company headquartered in Tokyo, Japan, with multiple offices around the world. The company's involvement in the arcade game industry began as a Japan-based distributor of coin-o ...
in 2005, Sega moved on to DVD discs and continued to use satellite and internet technology in the arcade. The last disc-based Naomi 2 and Triforce games were released in 2006 which marked the final releases using the GD-ROM format.
History
The format was developed for
Sega
is a Japanese multinational corporation, multinational video game and entertainment company headquartered in Shinagawa, Tokyo. Its international branches, Sega of America and Sega Europe, are headquartered in Irvine, California and London, r ...
by
Yamaha Yamaha may refer to:
* Yamaha Corporation, a Japanese company with a wide range of products and services, established in 1887. The company is the largest shareholder of Yamaha Motor Company (below).
** Yamaha Music Foundation, an organization estab ...
, and first commercially appeared with the Dreamcast's Japanese launch in November 1998. GD-ROM was created because the standard CD-ROM was prone to piracy and reaching the limits of its storage capacity, while implementing the then brand-new
DVD-ROM
The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any ki ...
technology would have made console production too costly. However, the Dreamcast did retain the ability to read standard CD-ROM discs, and thus still suffered from software piracy as bootleggers managed to fit certain games on CDs and exploit the Dreamcast console's compatibility with the
MIL-CD
MIL-CD or Music Interactive Live CD is a compact disc format created by the video game company Sega in 1998. The main purpose of MIL-CD was to add multimedia functions to music CDs, for use in Sega's Dreamcast video game console. For example, MIL- ...
format. As the GD-ROM format can hold about of data,
illegally copying Dreamcast games onto a CD-ROM sometimes required the removal of certain game features, although this did not prevent piracy.
The main difference between GD-ROM and MIL-CD is that MIL-CD can boot on an unmodified Dreamcast like original SEGA's disk, making piracy extremely easy. At the end of 1999 Sega released a new revision of the Dreamcast hardware which was not able to boot MIL-CDs, therefore preventing piracy.
Before the Dreamcast was released, Sega "confirmed that Dreamcast owners will one day be able to upgrade the GD-ROM drive to DVD," as information indicated Sony's upcoming
PlayStation 2
The PlayStation 2 (PS2) is a home video game console developed and marketed by Sony Computer Entertainment. It was first released in Japan on 4 March 2000, in North America on 26 October 2000, in Europe on 24 November 2000, and in Australia on 3 ...
would use the DVD format with its much larger capacity 4.7 GB single-layered up to 8.5 GB double-layered discs compared to the 1 GB capacity of the GD-ROM. Despite displaying a Dreamcast DVD display unit at E3 2000, the plans for a DVD add-on or fully separate unit never materialized during the short production run of the Dreamcast.
GD-ROM was also made available as an upgrade for the Dreamcast's arcade cousin,
Sega NAOMI
Sega is a video game developer, publisher, and hardware development company headquartered in Tokyo, Japan, with multiple offices around the world. The company's involvement in the arcade game industry began as a Japan-based distributor of coin-o ...
and the later
Sega NAOMI 2
Sega is a video game developer, publisher, and hardware development company headquartered in Tokyo, Japan, with multiple offices around the world. The company's involvement in the arcade game industry began as a Japan-based distributor of coin-o ...
, providing alternate media to its cartridge-based software. It is also used as an option on both the
Sega Chihiro
Sega is a video game developer, publisher, and hardware development company headquartered in Tokyo, Japan, with multiple offices around the world. The company's involvement in the arcade game industry began as a Japan-based distributor of coi ...
and
Triforce
The is a fictional artifact and icon of Nintendo's ''The Legend of Zelda'' series of video games. It first appeared in the original 1986 action-adventure game ''The Legend of Zelda'' and is a focus of subsequent games in the series, including ...
.
Regions
There are three data areas on a GD-ROM disc. The first is in conventional CD format, and usually contains an audio track with a warning that the disc is for use on a Dreamcast, and can damage CD players. These vary by region. This section is 4 minutes long with the data size of 35
MB.
The CD section also contains a data segment, which is only readable in PCs. Although most discs include only text files identifying the game, its copyright and bibliography, some contain bonus material for home computer users (for example, ''
Sonic Adventure
is a 1998 platform game for Sega's Dreamcast and the first main '' Sonic the Hedgehog'' game to feature 3D gameplay. It follows Sonic the Hedgehog, Miles "Tails" Prower, Knuckles the Echidna, Amy Rose, Big the Cat, and E-102 Gamma in their ...
'' contains images of
Sonic characters to use on the desktop). There then follows a separator track which contains no data except for the text ''Produced by or under license from Sega Enterprises LTD Trademark Sega'' (Similar to the
Sega Saturn
The is a home video game console developed by Sega and released on November 22, 1994, in Japan, May 11, 1995, in North America, and July 8, 1995, in Europe. Part of the fifth generation of video game consoles, it was the successor to the succ ...
, it was believed that the security key was stored in this area to prevent piracy). The final (outer) section of the disc contains the game data itself in a higher density format. This section is 112 minutes long (almost two hours), with a data size of 1.0
GB.
A normal CD-reader will not read beyond the first track because, according to the CD
table of contents
A table of contents, usually headed simply Contents and abbreviated informally as TOC, is a list, usually found on a page before the start of a written work, of its chapter or section titles or brief descriptions with their commencing page number ...
(TOC), there is no data there. With modified
firmware
In computing, firmware is a specific class of computer software that provides the low-level control for a device's specific hardware. Firmware, such as the BIOS of a personal computer, may contain basic functions of a device, and may provide h ...
on a few optical drive models that looks for a second TOC in the high-density region it is possible to read data from the high-density region. One can also utilize a "swap-trick" by first letting the CD-reader read the TOC from an audio CD with a special 99 minute TOC and then swapping that disc with a GD-ROM in a way that avoids alerting the CD-reader that a new disc has been inserted. It is then possible to read as much data from the high-density region as indicated by the TOC from the first disc.
The most popular way to access data from GD-ROMs, however, is to use the Dreamcast itself as a drive, and copy the data to a computer by means of a "coder's cable" or a
Dreamcast Broadband Adapter
The Dreamcast is a home video game console by Sega, the first one introduced in the sixth generation of video game consoles. With the release of the Dreamcast in 1998 amid the dot-com bubble and mounting losses from the development and introducti ...
. Another alternative is modding the Dreamcast to add a USB connector.
Sega has discontinued production of GD-ROM media.
Warnings
The second section (in conventional CD format) usually contains a message informing users that the disc can damage AV equipment. This is possible because a
CD player
A CD player is an electronic device that plays audio compact discs, which are a digital optical disc data storage format. CD players were first sold to consumers in 1982. CDs typically contain recordings of audio material such as music or aud ...
can interpret the game data track as an audio track, which will result in loud noise being played through the speakers. Different discs, usually varying by region, contain different messages.
NTSC-U discs usually contain the message, "Warning: This disc is only for use on Sega Dreamcast.", "This disc is for use only on Sega Dreamcast." or "This is a Dreamcast game disc. The first track contains game data. Please, do not play it on a normal CD player." Some discs contain light-hearted or humorous messages from the game's characters (for example, ''
Skies of Arcadia
''Skies of Arcadia'' is a 2000 role-playing video game developed by Overworks and published by Sega. Players control Vyse, a young air pirate, and his friends as they attempt to stop the fictional Valuan Empire from reviving ancient weapons with t ...
'' gives the message, "We can't save the world from a CD player, so just put us back in the Dreamcast so we can do our job!"). This is also common on NTSC-J discs.
PAL region discs contain the message, "This is a Dreamcast disc, and is for use only on a Dreamcast unit. Playing this disc on a hi-fi or other audio equipment can cause serious damage to its speakers. Please stop this disc now." The message is also repeated in French, German, Spanish and Italian. Some PAL region games, however, use the NTSC messages.
Technical information
The GD-ROM in the Dreamcast works in
constant angular velocity
In optical storage, constant angular velocity (CAV) is a qualifier for the rated speed of any disc containing information, and may also be applied to the writing speed of recordable discs. A drive or disc operating in CAV mode maintains a const ...
(CAV) mode, like the majority of modern optical drives. Very old CD-ROM drives read with a
constant linear velocity
In optical storage, constant linear velocity (CLV) is a qualifier for the rated speed of an optical disc drive, and may also be applied to the writing speed of recordable discs. CLV implies that the angular velocity (i.e. rpm) varies during an ...
(CLV) design, however (usually 12× or slower). Sega achieved the higher density by decreasing the speed of the disc to half and by letting the standard CD-ROM components read at the normal rate thus nearly doubling the disc's data density. This method allowed Sega to use cheaper off-the-shelf components when building the Dreamcast.
The
NetBSD
NetBSD is a free and open-source Unix operating system based on the Berkeley Software Distribution (BSD). It was the first open-source BSD descendant officially released after 386BSD was forked. It continues to be actively developed and is a ...
project has developed a GDRom driver for NetBSD. A port of that driver for
Linux
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...
exists, though due to licensing issues and the poor compatibility of that driver with Linux kernel interfaces, a new Linux driver is under development.
Linux kernel
The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU ope ...
2.6.25 comes with support for the GD-ROM drive on the Dreamcast.
See also
*
Nintendo optical discs
Nintendo optical discs are physical media used to distribute video games on three of Nintendo's consoles that followed the Nintendo 64. These are the GameCube Game Disc, Wii Optical Disc, and Wii U Optical Disc. The physical size of a GameCube Ga ...
*
Double-density compact disc The double-density compact disc (DDCD) is an optical disc technology developed by Sony using the same laser wavelength as a compact disc, namely 780 nm. The format is defined by the ''Purple Book'' standard document. Unlike the compact-disc technolo ...
*
MIL-CD
MIL-CD or Music Interactive Live CD is a compact disc format created by the video game company Sega in 1998. The main purpose of MIL-CD was to add multimedia functions to music CDs, for use in Sega's Dreamcast video game console. For example, MIL- ...
*
Universal Media Disc
The Universal Media Disc (UMD) is a discontinued optical disc medium developed by Sony for use on its PlayStation Portable handheld gaming and multimedia platform. It can hold up to 1.8 gigabytes of data and is capable of storing video games, ...
References
External links
Sega's GD-ROM Presentation
{{DEFAULTSORT:Gd-Rom
Computer-related introductions in 1998
120 mm discs
Dreamcast
Sega hardware
Video game distribution