There was actually only a short period of time when only write-once DVDs existed. By 2005 just about any computer DVD drive you could buy supported all combinat

There was actually only a short period of time when only write-once DVDs existed. By 2005 just about any computer DVD drive you could buy supported all combinations of {CD,DVD}±{R,RW} that existed. Blank RW disks were, of course, more expensive than R's, though.