Why are storage devices are output and input?

Storage devices are considered both input and output devices because they can receive data (input) from a computer system to store it for later use, and they can also provide data (output) back to the computer system when requested. For example, when you save a document to a hard drive, the hard drive acts as an input device by receiving the data. When you retrieve that document later, the hard drive acts as an output device by providing the data back to the computer system for display or processing.