I really wish I could rate this book higher because some of the material it covers is good for IT people who might not fully understand how some parts of the computer work, such as the processor, RAM, and cache memory.
However, the book also has a number of glaring errors that should have been caught during the editing process, such as information about Charles Babbage's Difference Engine and the difference between PCI-X and PCIe slots.
When a book can't bother to get easily identified facts right, I question the overall validity of the book as a whole.