CD-ROM² systems/Boot ROM

Back to: CD-ROM² systems.

The original Japanese CD-ROM² boot ROM, version 1.00. Note the lack of a superscript ² next to "CD-ROM" in the title, which was added in subsequent revisions.

One of the most important components in a CD-ROM² system is a boot ROM - an interface which appears when the console is given power. While a PC Engine HuCard can boot almost instantaneously, CD-ROMs require verification and loading, which depending on the quality of the disc or drive, can take several seconds. In addition to help drive the CD-ROM, the CD-ROM² boot ROM informs the user that the console is in CD-ROM² mode, and crucially gives them something more interesting to look at than a blank screen.

The boot ROM was originally not something built-in to the original CD-ROM² unit nor the Interface Unit, but was rather distributed in the form of special HuCards known as System Cards to be inserted into the PC Engine or TurboGrafx-16, allowing these systems to interface with the CD-ROM² unit. All later units, such as the Super CD-ROM² unit as well as the PC Engine Duo and its variants, come with the boot ROM pre-installed.

Functions

Compared to later CD-based systems from other manufacturers, CD-ROM² boot ROMs feature a basic interface and offer the same functionality - principly to run CD-ROM² games. Most models can also play music CDs, with support for CD+G discs added in version 2.00 onwards. Upon boot, the user is instructed to press  RUN  to boot the inserted disc, displaying "LOAD ERROR!" if the disc could not be recognised.

In addition, the user can manage data saved within the CD-ROM² unit's 2kB backup RAM by pressing  SELECT  on the main screen to display a menu. In this menu, the user can choose to delete specific files they no longer need to make room for new files, or format the backup RAM entirely.

Version 2.10, available exclusively in Japan on stand-alone System Cards, added the ability to auto-detect disc changes. Version 3.00, designed for the Super CD-ROM² format, has "SUPER" appended to the main screen and was distributed on Super System Cards, as well as on the Arcade Card Pro and Arcade Card Duo.

Screenshots

Main screen

• 

  JP 1.00

• 

  JP 2.00

• 

  US 2.00

• 

  JP 2.10

• 

  JP 3.00

• 

  US 3.00

Audio CD playback

• 

  JP 1.00

• 

  JP/US 2.00-3.00

Backup RAM menu

• 

  JP 1.00-3.00

• 

  US 2.00-3.00

Hidden content

Main article: CD-ROM² systems/Boot ROM/Hidden content.

Production credits

• PRODUCER: 中本伸一
• DIRECTOR: 野沢勝広
• CD-ROM SIMULATOR: 本迫芳夫
• BIOS MAIN CODE, CD-PLAYER: 小林敬樹
• BIOS CHECK MONITOR, SRAM MANAGER: 飛田雅宏
• BACKUP MEMORY MAINTENANCE: 金田孝司
• CD-PLAYER SUB: 三上　哲
• PSG DRIVER: 岩淵貴幸
• GRAPHIC DRIVER: 岩崎啓真
• GRAPHIC DRIVER SUB: 及川克之
• 8x8 ANK FONT: 松浦浩司
• CD-PLAYER DESIGN: 伊藤真樹
• TITLE DESIGN: 武田真理
• 12x12 KANJI FONT: 角谷　篤, 山口もと, 岡田寿夫
• NEC Home Electoronics: 鈴木孝治, 牧野　孝, 益子泰尚, 野坂和彦, 新井宏昭

1988 Sep. Written by TAKAKI KOBAYASHI

Source:

Hidden in ROM data

Technical information

ROM dump status

System	Hash	Size	Build Date	Source	Comments
?	CRC32 3f9f95a4 MD5 2b7ccb3d86baa18f6402c176f3065082 SHA-1 a39a66da7de6ba94ab84d04eef7afeec7d4ee66a	256kB	1988-09	Card (JP)	v1.00
?	CRC32 52520bc6 MD5 3a456f0eccff039eb5ff045f56ec1c3b SHA-1 f92ea593c8a935f58f8e1c3b2fc730951ec4fa71	256kB		Card (JP)	v2.00
?	CRC32 283b74e0 MD5 3cdd6614a918616bfc41c862e889dd79 SHA-1 88da02e2503f7c32810f5d93a34849d470742b6d	256kB		Card (JP)	v2.10
?	CRC32 6d9a73ef MD5 38179df8f4ac870017db21ebcbf53114 SHA-1 79f5ff55dd10187c7fd7b8daab0b3ffbd1f56a2c	256kB		Card (JP)	v3.00
?	CRC32 ff2a5ec3 MD5 94279f315e8b52904f65ab3108542afe SHA-1 2bea3dac98f84b2f2f469fa77ea720b8770d598d	256kB		Card (US)	v2.00
?	CRC32 2b5b75fe MD5 0754f903b52e3b3342202bdafb13efa5 SHA-1 d02611d99921986147c753df14c7349b31d71950	256kB		Card (US)	v3.00