Operating Systems Internals is a practical engineering guide to the layer between programs and hardware — the kernel, its abstractions, and the machinery that makes modern systems work. It covers system calls, processes and threads, virtual memory, memory allocation, filesystems, the I/O subsystem and drivers, inter-process communication, concurrency primitives, asynchronous I/O, security and isolation, and debugging with strace, perf, ftrace, and bpftrace. Along the way it addresses the failure modes that quietly break real systems — page faults that deadlock, priority inversions that starve threads, file descriptor leaks that exhaust the process table, write calls that return before data is durable, IPC deadlocks that only appear under load — each with the countermeasure and the operational tradeoff.
