The Yellow Book is the informal name for Philips and Sony's ECMA-130 standard specification for compact disc, read-only-memory (CD-ROM). Published by the two companies in 1988, the Yellow Book is an extension of the Red Book that enables the CD to contain data other than audio data. In 1989, the Yellow Book was issued by the International Organization for Standardization (ISO) as ISO/IEC 10149, Data Interchange on Read-Only 120mm Optical Discs (CD-ROM). Because the Yellow Book only defines the physical arrangement of the data on the disc, other standards are used in conjunction with it to define directory and file structures. They include ISO 9660, HFS (Hierarchical File System, for Macintosh computers), and Hybrid HFS-ISO.
In addition to the disc specification, optical stylus parameters, the control/display system, and sector structure, the Yellow Book includes modulation and error correction data. Definitions include two data modes, mode 1 and mode 2.
CD-ROM, Mode 1 is the standard data storage mode used by almost all standard data CDs (CD-ROMs). Of the 2,352 bytes of data in each block, 2048 are allocated for the data that the user sees. The remaining 304 bytes are used for added error detection and correction code.
CD-ROM, Mode 2 can contain 2336 bytes of user data. It is the same as Mode 1, except that the error detection and code correction bytes are not included. The Mode 2 format offers a flexible method for storing graphics and video. It allows different kinds of data to be mixed together, and became the basis for another standard known as CD-ROM XA (Extended Architecture). The specification for CD-ROM XA was published as an extension to the Yellow Book in 1991.