Computer Systems, Second Edition provides students with a broad understanding of all levels of computer systems. It emphasizes computer science topics that are related to, but not usually included in, the treatment of hardware and its associated software. The topics are presented through a unified concept of computer systems. The book allows students to explore several levels, such as high-order languages, machine, assembly, and logic gate through a top-down approach. Computer Systems, Second Edition covers the core topics in the Architecture and Organization category of the ACM and IEEE Curriculum 2001 Guidelines for Computer Science. This comprehensive approach supplies students with a fundamental understanding of computer systems. The Architecture and Organization (AR) core areas from the preliminary report, together with the chapters from this text that cover each area, are AR1. Digital logic and digital systems - Chapter 10, 11, AR2. Machine level representation of data - Chapter 3, AR3. Assembly level machine organization - Chapter 4, 5, 6, AR4. Memory system organization and architecture - Chapter 9, AR5. Interfacing and communication - Chapter 8, AR6. Functional organization - Chapter 11, AR7. Multiprocessing and alternative architectures - Chapter 8. This book has an integrated computer assembly language simulator integrated throughout.