I can't blame anyone for being confused. We've got three types of optical discs (CDs, DVDs, and BDs), with five different capacities between them. There are discs you can only read from, discs you can also write to, and discs you can write to, erase, and write to again. And the acronyms aren't always helpful.

Let's start with the acronym that appears the hyphen, which tells you the standardized disc format:

Compact Disc. These hold about 700MB of data. A CD drive can only read or write CDs.

Digital Video Disc or Digital Versatile Disc. They usually hold about 4.7GB. DVD drives can also handle CDs.