The Machine Hierarchy

We can view a typical computer as an upside down layer cake:

The hardware layer is made out of circuit boards and computer chips. It can do basic arithmetic and logic and is hard to use.

The other layers are made out of software. They are progressively richer in what they can do and are easier to use.

The operating system layer makes the computer work like a virtual office.

Most people know computers through the applications or programs that run on them. Word processors, web browsers, and games constitute the application layer.

The application layer is the user's view of the computer. The programming layer is the programmer's view.