Code: The Hidden Language of Computer Hardware and Software, 2nd Edition

Chapter Twenty-Five

Peripherals

The central processing unit (CPU) is certainly the most important component of a computer, but it must be supplemented with other hardware. As you’ve seen, a computer also requires random access memory (RAM) that contains both machine-code instructions for the processor to execute and data for these instructions to access. As you’ll also recall, RAM is volatile—it loses its contents when the power is turned off. So another useful component of a computer is a long-term mass storage device that can retain code and data in the absence of power.

The computer must also include some way for those instructions to get into RAM, and some way for the results of the program to be examined. Modern computers also have microphones, ...