DVD CDs

DVD, also known as "Digital Versatile Disc" or "Digital Video Disc," is an
optical disc storage media format. Its main uses are video and data storage. DVDs
are of the same dimensions as compact discs (CDs) but store more than six times
as much data.

Variations of the term DVD often describe the way data is stored on the discs:
DVD-ROM (Read Only Memory), has data that can only be read and not written, DVD-R
and DVD+R can record data only once and then function as a DVD-ROM. DVD-RW,
DVD+RW and DVD-RAM can both record and erase data multiple times. The wavelength
used by standard DVD lasers is 650 nm,[1] and thus the light has a red color.
DVD-Video and DVD-Audio discs respectively refer to properly formatted and
structured video and audio content. Other types of DVDs, including those with
video content, may be referred to as DVD-Data discs.

As next generation High Definition more advanced optical formats such as Blu-ray
Disc also use a disc identical in some aspects, the original DVD is occasionally
given the retronym SD DVD (for standard definition).[2][3] However, the
trademarked HD DVD discs have been discontinued since Blu-ray absorbed their
market share.