CD-ROM Standards

During the development of the CD-ROM format, the standards have evolved into what we have now today – a very standard interface in which all CD-ROM manufacturer use the same standard. In the beginning days, this was not the case, and the new medium was plagued with compatibility issues. But, manufacturers quickly handled this problem. The first standard was known as High Sierra, named after the California hotel in which major manufacturers met to agree upon the standard. The resulting, agreed-on standard was named the High Sierra format, and this dictated the structure of files on a CD. High Sierra remained the standard until the adoption of ISO 9660.

ISO 9660 was adopted because High Sierra was basically a United States creation and was this geared toward U.S. needs, without taking into account the needs of international markets. So, High Sierra was refined and tweaked and released as 9660. All current CD-ROMs used the ISO 9660 format, and this means that software can be written to use all CD-ROM drives without special needs.

Some of the different standards for CD-ROM technology are bound in different color booklets, with all documentation. They are:

• Red Book – the standard dictating the CD Audio standard. All audio CDs comply with this standard.


• Yellow Book – the standard which defines CD-ROM technology, the use of CDs for computer data. Mode 1 refers to the normal operating mode, whereas Mode 2 refers to using compressed data. Since the yellow standard is built off of the red standard, CD-ROM drives are all capable of playing audio CDs as well.


• Orange Book – the standard on which recordable CD technology is built upon.


• Green Book – Defines the standard for CD-Interactive


• White Book – Defines the standards for CD-ROM video.

One last standard is worth mentioning, and that is named El Torito, a standard which provides the hardware and software specs needed to implement a bootable CD-ROM. Normally, a CD-ROM requires drivers to operate correctly, so the PC must boot first so that the drivers can be loaded. This requires a floppy or hard drive. So, typically, if you want to use your CD-ROM to install an operating system, for example, you would have to boot first with a system disk, install the CD-ROM drivers somehow, then you can use the CD-ROM. El Torito was developed in 1995. To use it, you need a supporting drive, a BIOS that supports the ability to boot from a CD-ROM, and a CD with the necessary system files and operating system files to successfully boot the system.