What does an external DVD writer do?

Answer 1

An external DVD burner works essentially the same as an internal DVD burner, taking data from the computer and writing it onto a DVD disc. The main difference is that an external burner connects to the computer via a cable, typically through the USB port.

Answer 2

A DVD burner, or writer, is a device which encodes data onto a DVD. Some can burn one-time use DVDs while others can also burn re-writable ones. An external DVD burner is a type of DVD writer that is portable, not located inside a computer's case, and can be swapped from one computer to the other with relative ease, generally using a USB cable.