xv6, a simple Unix-like teaching operating system       xv6 book       source code booklet

[ostep] Operating Systems: Three Easy Pieces, by Remzi H. Arpaci-Dusseau and Andrea C. Arpaci-Dusseau

[vmbook] Virtual Machines: Versatile Platforms for Systems and Processes, James E. Smith, Ravi Nair.

Operating System Concepts, by Silberschatz, Galvin and Gagne

Think OS A Brief Introduction to Operating Systems, by Allen B. Downey