Structured computer organization

Chapter 1: Introduction

This chapter introduces the fundamental concept of a computer system as a hierarchy of levels, each built upon the one below it. It discusses the historical evolution of computers, from early mechanical devices to modern electronic machines, highlighting key figures like Babbage and Von Neumann. The chapter establishes the Von Neumann architecture as a foundational model, detailing its components: CPU, memory, and I/O. It also provides an overview of the different layers of abstraction that will be explored throughout the book, such as the digital logic level, microarchitecture level, and instruction set architecture level, setting the stage for a structured understanding of computer organization.

Chapter 2: The Digital Logic Level

This chapter delves into the lowest hardware level, explaining how computers are built from basic electronic components. It begins with Boolean algebra and logic gates (AND, OR, NOT, XOR, NAND, NOR), showing how these form the building blocks of digital circuits. Combinational circuits like adders, multiplexers, decoders, and shifters are discussed, illustrating how they perform operations without memory. The chapter then introduces sequential circuits, including flip-flops (SR, D, JK, T), registers, and counters, which incorporate memory and state. Finally, it covers the organization of memory, distinguishing between RAM (SRAM, DRAM) and ROM, and explaining how these components store and retrieve data.

Chapter 3: The Microarchitecture Level

This chapter explores the microarchitecture level, which implements the instruction set architecture using microprograms. It introduces the concept of a data path, comprising registers, ALUs, and internal buses, which are controlled by microinstructions. The control store, a special memory holding these microprograms, is detailed, explaining how microinstructions fetch, decode, and execute machine instructions. The chapter often presents a concrete example, such as the Mic-1 or a similar simplified CPU, to illustrate how a complex instruction like ADD or MOV is broken down into a sequence of simpler micro-operations, demonstrating the execution cycle and the role of the microprogrammer.

Chapter 4: The Instruction Set Architecture Level

This chapter focuses on the Instruction Set Architecture (ISA), which defines the interface between software and hardware. It covers the design principles of instruction sets, including instruction formats (e.g., fixed vs. variable length), addressing modes (e.g., immediate, direct, indirect, register, indexed), and the types of instructions (data movement, arithmetic/logic, control flow like branches and jumps). The chapter often uses a generic or simplified ISA to demonstrate how machine language programs are structured and executed. It also discusses the differences between CISC (Complex Instruction Set Computer) and RISC (Reduced Instruction Set Computer) architectures, highlighting their respective advantages and disadvantages in terms of performance and complexity.

Chapter 5: The Operating System Machine Level

This chapter examines the layer provided by the operating system, which manages hardware resources and provides a more convenient interface for application programs. Key topics include memory management techniques such as virtual memory, paging, and segmentation, explaining how the OS translates virtual addresses to physical addresses and protects processes from each other. It also covers input/output (I/O) programming, discussing different I/O methods like programmed I/O, interrupt-driven I/O, and Direct Memory Access (DMA). The chapter elaborates on interrupts and traps, their handling, and their role in enabling the OS to respond to events and enforce system policies, thus creating a virtual machine for each process.

Chapter 6: The Assembly Language Level

This chapter bridges the gap between the ISA level and high-level programming by focusing on assembly language. It explains how assembly language instructions directly correspond to machine instructions, providing a symbolic representation that is more human-readable than raw binary. Topics include the structure of assembly programs, the use of registers, data types, and control flow constructs (loops, conditionals) implemented with jumps. The chapter also covers the role of assemblers, linkers, and loaders in translating assembly code into executable programs, and how system calls are made from assembly to interact with the operating system, demonstrating practical low-level programming concepts.

Chapter 7: Parallel Computer Architectures

This chapter introduces the concepts of parallel computing, addressing the limitations of single-processor performance. It begins with Flynn's taxonomy (SISD, SIMD, MISD, MIMD) to classify different parallel architectures. The chapter then delves into multiprocessor systems, discussing shared-memory architectures, cache coherence problems, and solutions like snooping and directory-based protocols. It also covers multicomputer systems, which use message passing for communication, and explores various interconnection networks (e.g., meshes, hypercubes). The goal is to explain how multiple processors can work together to solve problems faster, detailing the hardware and software challenges involved in designing and programming parallel systems.

"Structured Computer Organization" by Andrew Tanenbaum is a foundational text that delves into the architecture of computer systems. Aimed at students and practitioners alike, the book presents a structured approach to understanding how computers function, integrating hardware and software concepts. The text is known for its clarity and pedagogical style, making complex topics accessible to learners new to computer science.

The book is organized into several key sections that progressively build on each other, exploring the layers of computer organization from the hardware level up to the software interface.

1. Hardware Fundamentals: Tanenbaum begins with an introduction to the basic components of computer systems, including the CPU, memory, and input/output (I/O) devices. The author explains how these elements interact and form the basis of computer operation.

2. Data Representation: The book discusses how data is represented within a computer, covering binary systems, data types, and the significance of encoding information.

3. Machine Language and Assembly: Tanenbaum introduces machine languages and assembly languages, illustrating how high-level programming languages translate to machine instructions.

4. Architecture: The text explores various computer architectures, including the von Neumann model, and highlights the importance of system design choices in performance and efficiency.

5. Operating Systems: A substantial section is dedicated to operating systems, detailing their role in managing hardware resources and providing an interface for user applications.

6. Networking and Distributed Systems: The book concludes with discussions on networking principles and the complexities of distributed computing, emphasizing the interconnectedness of modern computer systems.