Matt Holder delves into the history of our display servers and introduces consoles.

CREDIT: Magictorch

In this month’s article, we are continuing our investigation of the internals of Linux distributions. In the last two articles of the series, we looked at the Linux kernel and discovered some of its capabilities, such as interacting with hardware, providing firewall functionality and a virtualisation platform, and much, much more. While we recommend reading the first two instalments, the content in this article can be considered as standalone and no prior knowledge is required.

This month, we are discovering the various ways in which we can interact with our distributions, from the humble console to the venerable X server, to the Wayland protocol, which has multiple implementations, including the Weston reference compositor.

The time of terminals

In many of our articles, you need to open a terminal application and run commands, which perform a task and then display output on the screen. This was one of the earliest ways to interact with the system and it takes time to learn the commands. If we go back in time, to the dark old days before we had internet access, learning about the commands we needed to use was not as simple as it is now – you probably had to visit your local library or book shop to borrow or purchase a book about the Linux operating system.

When using a terminal from a graphical user interface, this can be referred to as a virtual console. What we will discuss in the next paragraph is interaction with a console. This is not a historic skill to learn – many Linux servers are headless, meaning that access is via a protocol, such as SSH, and commands need to be run.

Before getting into display servers, let’s pretend we’re in the late ’90s or early 2000s. Before carrying out the following steps, ensure everything is saved and then press Ctrl+Alt+F3. This drops you to a console, which allows you to log in with your usual credentials and enter some commands. Long-running commands can be suffixed with & , which runs the command in the background and allows another task to be started as well. Experiment with running commands in the background and you’ll notice that you won’t see any output while the command runs. If you want to run multiple long-running tasks and see the output, you can press Alt+F2, Alt+F3 and so on, and this gives extra login prompts that you can use to log in. Switch between them with the Alt and F keys. Below is a list of commands that you can experiment with and enjoy the good old days.