What is ALSA in the Linux kernel?

Question

What is ALSA? I read the Wikipedia page but couldn't understand it. All I understand is that it is a module in the kernel that has something to do with sound.

What happens if you don't include it in the kernel, does it mean that the speakers won't work or something. I am asking because I am trying to install a version of Linux but I don't know if the kernel should include ALSA

Solution

ALSA stands for Advanced Linux Sound Architecture, I'd encourage you to poke around their project website if you're truly curious. Specifically I'd take a look at the "I'm new to ALSA pages & tutorials.

The ArchLinux wiki probably describes it the best.

The Advanced Linux Sound Architecture (ALSA) is a Linux kernel component which replaced the original Open Sound System (OSSv3) for providing device drivers for sound cards. Besides the sound device drivers, ALSA also bundles a user space library for application developers who want to use driver features with a higher level API than direct interaction with the kernel drivers.

This diagram is also helpful in understanding where the various components, ALSA, JACK, etc. fit with respect to each other & the kernel.

                      

And finally one more excerpt - How it works: Linux audio explained:

When it comes to modern Linux audio, the beginning is the Advanced Linux Sound Architecture, or ALSA. This connects to the Linux kernel and provides audio functionality to the rest of the system. But it's also far more ambitious than a normal kernel driver; it can mix, provide compatibility with other layers, create an API for programmers and work at such a low and stable latency that it can compete with the ASIO and CoreAudio equivalents on the Windows and OS X platforms.

So the bottom line is that ALSA is the layer that provides other audio software components access to the kernel, so to answer your question, yes you need it.

Comments

[S edwards]

you not necessarily need it on a server I think ? do you ?

[user3247608]

Thanx for that, a simple and clear explanation!

[Mark]

@Kiwy, if you just want simple alarm beeps, the PC Speaker driver can do everything you need (if the server has the hardware -- it's no longer as universal as it was twenty years ago). ALSA is only needed if you want more sophisticated sound.

[Ruslan]

Is it really so that phonon is on top of xine, which is on top of gstreamer etc.? I don't have any pulseaudio on my system, and I still have had xine working without having installing anything like pulseaudio and gst.