1.1. User Interface versus Graphical User Interface
Learning Objectives
You will be able...
• ...to explain what a User Interface is.
• ...to describe what a Graphical User Interface (GUI) is and list at least three features of a today's GUI.
Introduction
If you click on an arbitrary button (pdf, glossary or help button, etc.) or interactive item (interactive index, link, etc.) while
reading this lesson, you interact with the computer system.
When you sit in front of the screen of a running computer, you always face a User Interface (UI). As the name implies, a
User Interface is an interface between the user and the computer. The first user interfaces were command-line interfaces
where you only could interact with the computer by typing commands on the keyboard (some Unix users still use this
kind of interface). Today, we (Mac, Linux and Windows-Users) expect to interact with the computer using a mouse,
launching programs by clicking on icons, and manipulate various windows on the screen using graphical controls. Such
user interfaces are called Graphical User Interfaces (GUI), since they use graphics and pictures to represent the input and
output of a program.