PC Hardware in a Nutshell, 3rd Edition

Writable CD Formats

The physical and logical format used by writable CDs is defined in the rainbow books described in Chapter 10. The following sections provide an overview of how data is physically and logically stored on writable CDs. For further detail, refer to the rainbow books.

Tip

CD-R discs are manufactured with a pregroove track that is 600 nanometers (nm) wide with a 1,600 nm pitch. The pregroove includes an impressed timing wobble of ±30nm radial excursion at 22.05 KHz, with an FM carrier modulated at 1 KHz superimposed on the pregroove. This modulation provides an absolute clock signal (called absolute time in pregroove, or ATIP) that provides an absolute location reference for any sector on the CD-R disc. Absolute addresses on the CD-R disc are specified in the form HH:MM:SS using ATIP information. Audio CDs are addressable in this manner with resolution of 1 second (75 sectors). Data CDs are addressable to the individual sector level.