Cd’s

Enhanced CD, also known as CD Extra and CD Plus, is a certification mark of the Recording Industry Association of America for various technologies that combine audio and computer data for use in both compact disc and CD-ROM players. The primary data formats for enhanced CD disks are mixed mode (Yellow Book/Red Book), CD-i, hidden track, and multisession (Blue Book).

The technology was popular in the late 90s with the increase of computer usage. Music CDs often included music videos, wallpapers, and other various content. However, more recently, acts wishing to include enhanced content often include a DVD instead, with the advantage of it playing in both a computer's DVD-ROM drive and in a standard DVD player.

Sometimes computer CD-ripping programs (particularly cdparanoia) have problems ripping some enhanced CDs, especially those that have the data in a separate session after the audio section. These CDs have the data 11,400 sectors (2m32s) after the audio, but some CD rippers may try to rip this blank section with the last track; the end result is that the ripper stalls during the last track, or simply reports errors.

A Compact Disc (also known as a CD) is an optical disc used to store digital data, originally developed for storing digital audio. The CD, available on the market since October 1982, remains the standard physical medium for sale of commercial audio recordings to the present day. A thin layer of aluminum or, more rarely, gold is applied to the surface to make it reflective, and is protected by a film of lacquer that is normally spin coated directly on top of the reflective layer, upon which the label print is applied. Common printing methods for CDs are screen-printing and offset printing.