Hardware and software: what actually “is” the computer?

You buy a laptop. The salesman shows you the screen, the keyboard, the box that hums when it starts. You point at all of it and say “this is the computer”. He is only half right.

Unplug every wire and that box is still a laptop-shaped brick. Nothing happens until it is told what to do. A computer is a machine that can be programmed to accept data (input), process it into useful information (output), and store it for later.