Chrome OS unfortunately only supports data CDs/DVDs/Blurays (the file formats must also be supported). So no DVD films, audio CDs or similar. Only data can be read and not written. FAQ (in English): http://www.chromebookhq.com/chromebook...

As you can see, the Chromebook is practically unsuitable for external drives. Otherwise, you can use practically any plug&play-capable external drive: https://www.digitec.ch/de...