What Are Linux Distributions?

1. Introduction

A Linux distribution is an integrated collection of software packages, designed to be a complete operating system (OS) based on the Linux kernel. Unlike proprietary operating systems such as Windows or macOS, Linux distributions are usually composed of free and open-source software.

In this tutorial, we’ll discuss what Linux distributions are by first covering the Linux kernel, then the GNU userland, and finally, the Linux desktop.

2. Linux Distributions

A Linux distribution, often shortened as a distro, is a comprehensive package of software that forms a complete operating system. These distributions are specifically designed to cater to various user needs, ranging from servers and desktops to embedded systems. Unlike a single philosophy, a distribution is a practical implementation of software customized for specific purposes.

Distributions are designed based on different goals and user requirements. The versatility of Linux distributions comes from their modular structure. In other words, distros consist of several integrated components that work together to create a functional and efficient OS:

• Linux kernel
• GNU userland
• desktop environment

Notably, distributions don’t need to include a desktop environment, especially in use cases such as servers or embedded systems. Although only the first one is mandatory, the combination of these components ultimately forms what is known as the software stack.

3. The Linux Kernel

The kernel is the core component of any operating system. In the case of Linux, it’s referred to as the Linux kernel. In addition, it serves as the interface between the computer’s hardware and its processes. Moreover, it manages resources and facilitates communication between hardware and software.

Linux kernel handles various processes:

• Device Drivers: enable the kernel to communicate with hardware devices
• Process Management: handles the execution of processes, including multitasking, process scheduling, and inter-process communication
• Memory Management: manages system memory, ensuring efficient allocation and protection of memory spaces for different processes
• Filesystem Management: provides support for various filesystems

Hence, these processes ensure the efficient operation of the entire OS.

3.1. Device Drivers

Device drivers are specific types of system software that enable the kernel to communicate with hardware devices. In particular, these include drivers for graphics cards, network adapters, peripheral devices such as printers and USB drives, and others. In addition, these device drivers ensure that the Linux distribution can support a wide range of hardware configurations.

Moreover, device drivers are a critical part of the kernel that translates the generic commands from the operating system into specific actions that the hardware can perform. Therefore, a variety of device drivers ensures that the Linux kernel can support diverse hardware configurations, enhancing compatibility and performance.

3.2. System-Level Software

System-level software includes essential utilities and tools that manage and maintain the system. This includes everything from filesystem management tools to networking utilities and security features. Moreover, these tools are crucial for the administration and smooth operation of the Linux system.

Now, let’s look at some system-level software available around the Linux kernel:

• File System Management: tools that handle the creation, maintenance, and access of file systems, such as mkfs, fsck, and mount
• Networking Utilities: programs that manage network connections and configurations, like ip, netstat, and ifconfig
• Security Features: modules and utilities that enhance system security, such as SELinux (Security-Enhanced Linux) and firewalls like iptables

Hence, these essential tools ensure that a Linux kernel can be configured and administered for smooth operation.

4. The GNU Userland

The GNU userland is a collection of programs and tools that are fundamental to the functionality of a Linux distribution. GNU stands for GNU’s Not Unix, reflecting the project’s origins and philosophy. In other words, the philosophy of free software and open collaboration.

Moreover, this collection of software provides the tools needed for user interaction, system management, and software development.

4.1. User Interface Software

User interface software includes shells like bash (Bourne Again SHell), which provide a command-line interface for users to interact with the system. The shell interprets user commands and translates them into actions performed by the operating system. Other shells such as zsh and fish offer alternative user experiences.

4.2. Development Tools: Compiler, Linker, Parser-Generator

The GNU userland includes essential development tools such as compilers, linkers, and parser-generators, enabling users to develop software directly on the Linux system.

Moreover, compilers like GCC (GNU Compiler Collection) enable users to compile source code into executable programs. Additionally, the linker combines object files into a single executable, while parser-generators like Bison assist in the creation of language parsers. These tools can be indispensable for software development on Linux.

4.3. Application Software

The GNU userland also includes various application software designed to perform specific tasks:

• Emacs: a highly extensible text editor with powerful features for programming and text manipulation
• BC: an arbitrary-precision calculator that supports interactive execution of statements
• Coreutils: basic file, shell, and text manipulation utilities, including commands like ls, cp, mv, and grep

These applications provide essential functionality for everyday tasks and advanced computing needs.

4.4. System Libraries

System libraries are a collection of pre-written code that applications can use to perform common tasks. Let’s look at some of the system libraries that are part of the GNU userland:

• GNU C Library (glibc): the core library for the Linux system, providing essential APIs for system calls, memory management, and I/O operations
• libstdc++: the standard C++ library, offering support for C++ language features and standard templates
• OpenSSL: a toolkit for secure communication protocols, widely used for secure network communication

Thus, these libraries collectively enhance the capabilities of the GNU userland. In other words, these ensure efficient and secure software development on Linux.

4.5. Package Management Systems

An essential aspect of Linux distributions is their package management systems, which handle the installation, update, and removal of software. In addition, these systems manage software packages and their dependencies, ensuring that the software stack remains consistent and up-to-date. Some of the package management systems include APT, YUM, and Pacman.

Moreover, package management systems involve various tools:

• Package Managers: Tools like APT (Advanced Package Tool) for Debian-based systems, YUM (Yellowdog Updater, Modified) for Red Hat-based systems, and Pacman for Arch Linux
• Shells: Command-line interfaces like Bash, Zsh, and Fish enable users to execute commands and scripts
• System Monitoring Tools: Applications like top, htop, and GNOME System Monitor provide real-time information about system performance and resource usage

Hence, package management systems are crucial for maintaining the integrity and security of the Linux distribution, providing a streamlined and user-friendly approach to software management.

5. Desktop Environment

A desktop environment provides a graphical user interface (GUI) for users, making it easier to interact with the system. As compared to the CLI, GUIs are widely popular. Popular desktop environments include GNOME, KDE Plasma, and XFCE.

A typical desktop environment includes several key components:

• Window Manager: manages the positioning and appearance of windows
• Panel: usually a bar that contains application launchers, a system tray, and various applets
• File Manager: provides a graphical interface to manage files and directories
• Desktop Widgets: small applications that run on the desktop and provide quick access to information tools
• Settings Manager: a centralized place to configure system and application settings

Now, let’s look at the main software components of a Linux desktop environment.

5.1. Hardware Abstraction Software

Within the desktop environment, hardware abstraction software ensures smooth communication between hardware devices. For example, PulseAudio manages audio devices, ensuring smooth playback and recording across different applications.

Similarly, NetworkManager simplifies network configuration and management. Hence, these tools abstract the complexity of hardware management, providing a consistent and user-friendly experience.

5.2. Application Software

A typical desktop environment also includes a suite of applications for user needs:

• word processor
• spreadsheet program
• Web browser
• media player
• convenience software

Moreover, such applications can be essential for everyday tasks and make the Linux desktop environment a viable alternative to other operating systems.

6. Variations in Distros

Linux distributions can vary significantly in their design and functionality. The variations depend on the different user needs and preferences. Let’s go over some of the key components that often differ between distributions.

6.1. General Use and Specialized Distributions

General use distributions are user-friendly and suitable for a wide range of applications. For example, Ubuntu is a popular general-use distribution that offers versions for desktops, netbooks, and servers.

On the other hand, specialized distributions are designed for specific purposes or environments. For instance, CHAOS is a small operating system designed to run on high-performance computing cluster nodes. Another example is TinyCore, which is made for use on old hardware, focusing on minimal resource usage.

6.2. Design Decisions

Distributors often make design decisions on behalf of the user based on what they expect the user wants. These decisions include desktop environments, pre-installed software, and package management systems.

To begin with, different distributions may come with different default desktop environments. For example, Ubuntu typically comes with GNOME, while Kubuntu (a variant of Ubuntu) comes with KDE Plasma. This affects the overall look and feel of the operating system.

Furthermore, the selection of pre-installed applications can vary. For example, Ubuntu includes LibreOffice and Firefox by default.

Lastly, package management software, which is part of the GNU userland, varies between distributions. Different distributions use different package managers to handle software installation, updates, and removals. For instance, Debian-based systems like Ubuntu use APT, Red Hat-based systems use YUM or DNF, and Arch Linux uses Pacman.

7. Conclusion

In this article, we covered what Linux distributions are and defined them as a collection between the Linux kernel, GNU components, and a desktop environment.

First, we discussed the main kernel and its components. After that, we explored the GNU userland. Then, we covered the Linux desktop environment. lastly, we went through distribution variations.

In conclusion, Linux distributions bundle various components together usually towards a given goal. This makes it easier for users to get a fully functional operating system without having to build it themselves.