The proposed second generation of compact discs, developed independently by Philips/Sony and Toshiba/Time Warner. Two varieties of HDCD allow for much higher storage capacities than conventional, first generation CDs. The Philips/Sony disc, called the multimedia CD, can hold up to 3.7 gigabytes. The Toshiba/Time Warner disc, called the super density format, is double-sided and can hold up to 4.2 gigabytes per side. Higher storage density is achived by using a red laser, which possesses a shorter wavelength.
However, both versions of the HDCD were incorporated into a new standard format adopted by the computer industry called the digital versatile disc, which includes a double-sided, double-layer technology developed by 3M that allows for a capacity of 4.7 gigabytes per side per layer, for a total capacity of 17 gigabytes. See Digital Versatile Disc.