Getting Started

User Interfaces

Introduction
The way a computer looks when you use it is a function of its Graphical User Interface (GUI), which defines the "look and feel" of the operating system. A GUI is a visual way you interact with a program. When you use a graphical program (including an operating system), you are dealing with a GUI, not the actual program. In Windows and Mac OS, you don't have a lot of say in the GUI you use, as you are pretty much only given one. (There are some exceptions. In Windows XP, for example, you can choose to have an appearance similar to the Windows 9X systems, or the new XP look and feel, but both are pretty much the same.) In Linux, however, there are a bunch of vastly different interfaces. Unlike Windows or Mac OS, Linux does not have a definitive "look and feel."

First, some terminology. You will probably hear people talking about both "X Windows" (or just "X") and "FVWM." (There may be some others, too.) Basically, X Windows is the tacit standard for displaying windows (all those frames that programs appear in) in Linux and other UNIX variants. So, almost any GUI for Linux or UNIX will use X Windows. While you can operate in straight X Windows, you would lack a lot of basic functionality, like menus, the ability to move and resize windows, etc. As a result, people have built a number of Window Managers that manage the X Windows and create a more robust environment.

FVWM
By default, your account uses a Window Manager called FVWM*. FVWM is one of the most minimal X Window Managers. It provides some simple menus, a virtual desktop (we'll explain that later), and key and mouse interaction. In fact, FVWM is so close to pure X Windows that you will often hear people just refer to the environment as X Windows. Technically, calling an environment X could imply any window manager, but if people say that they are using X (as opposed to Gnome or KDE, other window managers), they probably mean FVWM. If you really don't like making friends, you can start correcting everyone.

FVWM is the environment you get by choosing to start an XSession. This further muddles the nomenclature, as the "XSession" technically just starts straight X Windows, but your account has been configured to launch the FVWM manager when you start X. Bottom line: X is the toolbox, FVWM the window manager, and the two if them together create your GUI.

Why FVWM?
We have made FVWM the standard manager for a few reasons:

• Performance - FVWM has less overhead and and greater stability than most other managers. As a result, it runs faster and is less likely to crash.
• Usability - FVWM has some features, like the way it handles active windows and the virtual desktop, that make it well suited for a programming class.
• Flexibility - FVWM gives you more control over your environment than most other managers. It is almost infinitely customizable, whereas it can be more difficult to change the look and feel of another interface.

That said, you are welcome to play around with the other environments available on the Session menu. (The Session menu is in the upper-left corner of the login box.) You may find that you like another manager, such as KDE or Gnome (both of which have a feel more like Microsoft Windows), better than FVWM. However, this tutorial, and everything else in CS9, will be based on the assumption that you are using FVWM. If you choose to use another environment, things might not work exactly the same, and you should know enough to be able to sort it out, as the TAs might not know how to help you with another window manager. Unless you are very familiar with Linux, you should at least complete this tutorial using FVWM, as all of the screen shots and step-by-step instructions are based on that.

* Also referred to as FVWM2 because this is the second version, and it has some substantial performance differences from the first. We will probably use both terms throughout this tutorial, and when you hear FVWM around the department, you can bet FVWM2 is implied.