Afriend knows i'm taking a technology class in college and asks me how a hard drive works. what should i say to a friend about how a hard drive work.

professionals can use many types of technology that can them. some examples are, computers (they research and can use for programs for data, they are also used for job applications, school work, and even to make new ideas), speedometers (can get data for unknown data), sometimes something as small as a pen (used for rough drafts, to insert data, and again job applications).

(because i need 20 chars)