Copy-protection (C)

Recently, some major recording publishers have begun to sell CDs that violate the Red Book standard for the purposes of copy prevention, using systems like Copy Control, or extra features such as DualDisc, which features a CD-layer and a DVD-layer. The CD-layer is much thinner, 0.9mm, than required by the Red Book, which stipulates 1.2mm. Philips and many other companies have warned them that including the Compact Disc Digital Audio logo on such non-conforming discs may constitute trademark infringement; either in anticipation or in response, the long-familiar logo is no longer to be seen on recent CDs, as well as stickers and warnings that the CD is not standard and may not play in all CD players.