Comprehending the complex interaction between hardware and software is paramount for students of computer science. In Understanding Computer Organization, readers are taken on the journey through the fundamental building blocks underpinning modern computing systems. This unique textbook unlocks modern computer organizations' secrets, with real-world examples from RISC-V, ARM, and Intel-based computer systems. The guide provides a comprehensive yet accessible explanation of fundamental principles and components and serves as a gateway to mastering the interplay between hardware and software. It demystifies complex concepts and provides clear explanations and practical insights into their roles in computing systems. Topics and features: Provides comprehensive coverage of computer organization principles across three major architectures (RISC-V, ARM Cortex, and Intel), ensuring a broad understanding of modern computing Includes numerous practical explanations using real-world examples from each architecture, offering hands-on insights into memory-mapped I/O, interrupts, DMA, and various memory technologies Presents detailed exploration of diverse components such as interrupts and their usage, interrupt controllers, DMA transfers, and DMA controllers Offers exploration of DDRx SDRAM memory, SDRAM controllers, DIMM modules, caches, and virtual memory Concise and yet thorough, this useful textbook/guide equips readers with the knowledge and skills needed to navigate the complexities of computer organization, making it essential reading for students and professionals. Patricio Bulić is a computer engineering professor at the Faculty of Computer Science, University of Ljubljana, Slovenia.