The 1994 book by Curt Schimmel is a classic technical text focusing on how the UNIX kernel interacts with advanced hardware. It bridges the gap between traditional UNIX internals and the complexities introduced by high-performance hardware features like CPU caches and multiple processors. Core Technical Features
If you find the PDF, do not just skim it. Compile the example kernel module. Run it on a simulator. You will realize that "modern" is just a temporary label, but systems thinking is forever.
The second part examines tightly coupled, shared-memory multiprocessors.
To a casual user, it looks like a dry technical specification. But to a systems programmer or a digital archaeologist, those five words tell a dramatic story. 1994 was the year Unix faced its existential crisis. The "modern architectures" of the time—the MIPS R4000, the DEC Alpha, the HP PA-RISC, and the nascent Intel Pentium—were tearing apart the old assumptions of the 1970s and 80s.
Find it. Read the chapter on "Cache Coherency Protocols." And realize that every mutex_lock() in your Linux laptop contains a small ghost of that anxious, brilliant year when Unix stared into the pipeline and refused to blink.