DVD writers typically do it all, they both read and write both CDs and DVDs. All current DVD writers can write DVD+R, DVD+RW, DVD-R, and DVD-RW discs interchangeably. Most models can also write dual-layer DVD+R DL and/or DVD-R DL discs which store about 8.5 GB rather than the 4.7 GB capacity of standard single-layer discs. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.