This work anwers user's questions about their PCs, providing expert advice. It contains detailed explanations of core hardware topics including all CPUs, all co-processors, real, protected and virtual 8086 mode with Pentium enhancements, extended and expanded memory, interrupts, exceptions, NMI and much more. This edition also features: coverage of 386 and 486 clones from AMD, Cyrix, C&T and IBM, upgrades, overdrives and SLs; a new chapter devoted to multimedia; and extensive appendices which provide a programming reference. This work is intended for hardware and software engineers, system integrators, maintenance and support engineers.