Storage Management Strategies for the CIO
The Red Book is the 1980 document that provides the specifications for the standard compact disc (CD) developed by Sony and Philips. According to legend, the document was in a binder with red covers, originating the tradition for subsequent adaptations of CD specifications to be referred to as variously colored books. The Red Book described the CD's physical specifications, such as the tracks, sector and block layout, coding, and sampling. Sony and Philips referred to the discs as CD-DA (digital audio), defined as a content medium for audio data digitized at 44,100 samples per second (44.1KHz) and in a range of 65,536 possible values (16 bits).
The CD Format
According to Red Book specifications, a standard CD is 120 mm (4.75 inches) in diameter and 1.2 mm (0.05 inches) thick and is composed of a polycarbonate plastic substrate (underlayer - this is the main body of the disc), one or more thin reflective metal (usually aluminum) layers, and a lacquer coating. CDs are divided into a lead-in area, which contains the table of contents (TOC), a program area, which contains the audio data, and a lead-out area, which contains no data. An audio CD can hold up to 74 minutes of recorded sound, and up to 99 separate tracks. Data on a CD-DA is organized into sectors (the smallest possible separately addressable block) of information. The audio information is stored in frames of 1/75 second length. 44,100 16-bit samples per second are stored, and there are two channels (left and right). This gives a sector size of 2,352 bytes per frame, which is the total size of a physical block on a CD.
CD data is not arranged in distinct physical units; data is organized into frames (consisting of 24 bytes of user data, plus synchronization, error correction, and control and display bits) which are intricately interleaved so that damage to the disc will not destroy any single frame, but only small parts of many frames.
The Red Book specifications form the basis for all later CD technologies.