The source code and commentary of xv6, a simple Unix-like teaching operating system. By far the best book on operating systems I have encountered so far. https

The source code and commentary of xv6, a simple Unix-like teaching operating system. By far the best book on operating systems I have encountered so far. https://pdos.csail.mit.edu/6.828/2012/xv6.html https://pdos.csail.mit.edu/6.828/2012/xv6.html (The alternative is learning PDP-11 assembler and reading the original Unix v6 sources with Lion's commentary.)