This book introduce with computer system as well as architecture. In computer science, engineering and technology, Computer System and Architecture is the practical art of selecting and interconnecting hardware components to create computers that meet functional, performance the cost of goals and the formal modeling of those systems. The study of computer system and architecture is very important for the students of computer science, engineering and technology. This book on "Introduction to Computer System and Architecture" lays emphasis on theory and design of computer system. The book provides the basic knowledge and necessary awareness to understand the hardware operation of digital computer.