Case : the unit that contains the components of the computer system that enable data to be processed according to a series of instructions. It is also known as the system unit or console.

Enclosures :

Internal : Internal refers to drives that are installed inside a desktop computer.
External : External refers to drives that work outside of a computer, via some sort of connecting wire.

Plug-In Module : This refers to drives that are used inside of laptop computers.
Proprietary : Proprietary burners have much higher production output, and are generally used when making a very large number of copies.