I must admit to being confused by all the different sound systems available... Arts, OSS, Alsa, Esd, Esound, etc. I have no idea if these are all the same sort of thing, or if some are designed to work together, or operate at different layers, etc.
I have an old Aureal-based card, using drivers from the Aureal Linux Hacking page on Sourceforge, and although it works fine in XMMS, the MIDI support doesn't seem to work at all. Other sound support is patchy at best. My bundled movie-playing software that came with KDE/Mandrake 9 won't play the audio part of the movie clips. Backspacing in a console window produces a little bell icon but no sound, most of the time. The other day though, it did make a ding sound! 4 or 5 times, before a message box came up telling me there was a 'sound server CPU overload' at which point it stopped working

Also, no SDL-based games seem to be able to use sound. I am not at my Linux machine at the moment and therefore can't post a more accurate error message, but I think it said that it couldn't open /dev/audio. Yet obviously other systems work...
So I guess my post has 2 aspects to it:
a) Any idea why my sound support is patchy (besides the fact that I'm using unofficial drivers)? I understand that I will probably need to post more info to get a good answer, but I dunno what I need to post yet.
b) What is the status of all these sound systems, why do so many exist, and is there any kind of standardisation approaching?
BTW, if there's some sort of FAQ on this, I won't be offended if I'm merely pointed at it.

Any info is welcome.