Originally Posted by turboscrew
Does anybody have hints about where to find some higher level descriptions of the architectures of Linux subsystems, like sound,
There are so many subsystems these days that it's hard to find out which are exclusive, which can co-exist and which are used together.
That might depend entirely on the concrete systems you are interested in and the kernel version we speak about. It's quite a wide topic to give a comprehensive outlook on a single post or even a thread.
It's also hard to find out which are almost obsolete, which are coming and which are common.
The kernel documentation is -usually- a good place to know these details. Both the menuconfig help system and the docs under Documentation/ in your kernel source tree are good places to start researching.
If you want something basic, ALSA has taken over OSS3 (OSS4 is being developed in parallel though, but the range of hardware and functionality is nowhere near ALSA these days).
SATA is ruling out the old IDE drivers.
v4l and v4l2 are mostly the same thing today, though technically there's much more to it of course.