Final answer:
An external hard drive and music CDs/DVDs are magnetic storage media sealed in a case and used for storing and retrieving digital information. They utilize magnetic or optical technologies to provide high-capacity and quick access to data.
Step-by-step explanation:
An external hard drive is magnetic storage media usually sealed in a case inside the computer. It works by magnetically encoding information that can be stored or retrieved quickly. The information is stored on a coated, spinning disk, and read and written using a thin stylus.
Similarly, music CDs and DVDs store information digitally and have a larger information-storage capacity. They have pits made by a laser that are read by a laser beam scattering from the pits as the CD or DVD spins, revealing the encoded digital pattern and the information.
Both the external hard drives and CDs/DVDs use magnetic or optical technologies to store and retrieve data, providing high-capacity and quick access to information.