Understanding IO architecture

From: Mahmood Naderan
Date: Fri Jan 15 2016 - 04:00:37 EST

What is the good starting point to understand linux kernel? I know you
are going to say Understanding the Linux Kernel, but that is for 2005!
and kernel 2.6.

We know that currently, the latest version is 4.4 and the version
number updates quickly. So, where can I find the core of IO
architecture, page cache, block layer and ... for the most stable
architecture and not the version number?