The Advanced Linux Sound Architecture (ALSA) project is used to implement sound card drivers in Linux. Apart from the Kernel API, ALSA also provides a library API exposing the same functionality as the Kernel API but with a simpler and more usable interface. In this post, we will explore how the PCM Interface can be used for sound playback. There are quite a few options for dealing with audio on Linux. On one hand, we have high level libraries such as SDL or OpenAL that allow us to play a sound with a few lines of code. Then we also have entire frameworks devoted to multimedia such as GStreamer.

The X Window System is a windowing system commonly used in UNIX-based operating systems. The latest version of X is version 11 (released 2012), that’s why it’s often abbreviated as X11. X11 is based on a client-server architecture. The server is the one who has direct access over the hardware devices such as the monitor screens, the keyboard and the mouse. Client applications should make requests to the server in order to achieve any kind of graphical output to the screen. X is not the only Window System available for Linux and other UNIX-like operating systems. Wayland is a more modern project with the aim of replacing X.