GNU/Linux distribution timeline

Understanding Linux Distributions

Microsoft Windows is an Operating System (OS), so is GNU/Linux (often incorrectly referred to as only Linux). Windows OS has versions (Windows 2000, XP,Vista, 7, 8, 10) but GNU/Linux OS has distributions which in turn have versions (typically a number). These distributions (or distros) are a source of confusion for Windows users.

An operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs (applications). A typical OS installation will come with standard applications. So for the purpose of discussion here, we will consider these applications as well to understand the nuances.

GNU and Linux evolved as Free Software, allowing people to create variations. The upside is that it can be innovative. However, the downside is variations (or lack of consistency) which makes adoption for new users difficult. But once you know the underlying differences (and similarities), you will realize that they are all pretty much the same. Adopting and switching among the many distributions should be less intimidating. Some typical distributions are Debian, Ubuntu, Red Hat, CentOS, Fedora and Ubuntu.

Under the hood

The GNU/Linux OS and applications has the following systems (over simplified) under the hood.


Linux is the low level system program that interacts with the hardware and allocates the machine’s resources to the other programs that you run.

System Tools/Libraries

GNU software provides the low level Operating System functionalities.

Package Manager

Automates the process of installing, upgrading, configuring, and removing programs in a consistent manner.
Examples: dpkg, apt, rpm, yum and others

Graphical User Interface (Desktop Environment)

Desktop Environment provides the front end to an Operating System and its programs. It’s a set of programs that use a common Graphical User Interface (GUI) so all programs will have a similar look and feel. A Desktop Environment consists of a Window Manager 1 and a Windowing System 2.
Examples: GNOME, KDE, Xfce and others

User Applications

These are eventually the programs that make the computer and operating system useful to a large audience.
Examples: Text Editor, Music Player, Video Player and others

Finally, a Distribution

A combination of these systems will make up a distribution. So you can imagine the possible variations. Most variations come from the Package Manager, default GUI 3 and default applications. However, since the kernel and system tools/libraries are relatively constant, the core of any distribution is similar.


Historically, distributions have evolved over time each with it’s own development philosophy, plan and strategy. In some cases, active development may derive from another distribution. But the bottom line is that they are more similar than different – simply a GNU/Linux Operating System.

  1. The Window Manager controls the placement and appearance of windows within a windowing system. Most window managers are designed to help provide a desktop environment. It provides functionality to open, close, minimize, maximize, move, resize and keep track of running windows, including window decorators. Many window managers also come with additional utilities and features like docks, task bars, program launchers, desktop icons and wallpaper.
    Examples: Metacity(GNOME), KWin(KDE), Xfwm(Xfce) and others 
  2. The Windowing System manages separately different parts of display screens. It implements the windows, icons, menus and pointer paradigm for a user interface.
    Examples: X Window System, Wayland and others 
  3. Many distributions may even support multiple GUIs (Desktop Environments), so the user has the ability to pick one or switch at a later time.