CurtSchimmel has been working at SGI (http://www.sgi.com) for many years on Irix virtual memory and other system software.
His book "UNIX(TM) Systems for Modern Architectures: Symmetric Multiprocessing and Caching for Kernel Programmers" describes the SMP and cache architectures of various modern Unix systems. It presents an excellent and thorough coverage of CacheArchitecture? forces in his book on parallelizing Unix kernels. Further details on this book are on Amazon at: http://www.amazon.com/exec/obidos/ASIN/0201633388.