Introduction to Computer Architecture

Introduction to Computer Architecture and Organization

• A distinction exists between computer architecture and organization
• Architecture: Attributes visible to a programmer, impacting program execution. Includes instruction set, data representation, and input/output mechanisms.
• Organization: Operational units and connections that realize architectural specifications. Includes hardware details (e.g., control signals), and interface between computer and peripherals.

Structure and Function

• Computers are complex systems with millions of components.
• Hierarchical structure allows for description and design at different levels of detail.
• Structure: How components interrelate
  • Control Unit: Controls CPU operation
  • Arithmetic Logic Unit (ALU): Performs data processing
  • Registers: CPU storage
• Function: How each component operates within the system
• System description can follow either a bottom-up or top-down approach.

CPU Interconnections

• Mechanisms provide communication between control unit, ALU, and registers.
• Main Memory: Stores data and instructions
• Input/Output (I/O): Data transfer between computer and external environment
• System Interconnection: How different components interact

Data Movement

• Data movement between different sources and destinations within the computer system is key to its functioning.
• Data Storage: Where data is stored in the computer system.
• Data Processing: Where data is handled in the computer system.

Brief History of Computers

• First Generation (Vacuum Tubes): ENIAC, the first general-purpose electronic computer, used vacuum tubes, was large, and complex.

• Von Neumann Machine: Introduced stored-program concept where instructions are stored with data to the computer's memory.

• Commercial Computers: Sperry and IBM were early leaders, creating commercial computers such as UNIVAC I.

• Second Generation (Transistors): Transistors replaced vacuum tubes. This improvement resulted in smaller, more efficient, and cheaper computers. Key features included high-level programming language.

• Third Generation (Integrated Circuits): Integrated circuits (ICs) combined multiple components into a single chip, resulting in significant cost reduction, performance increase and smaller size; used small-scale integration (SSI).

• Fourth Generation: Development of (large-scale, very large-scale, etc.) integration led to the current era's mainframe computers.

• Fifth Generation: The development of AI, which led to the development of Artificial Intelligence.

• System/360: IBM introduced a family of computers (System/360) to meet varying performance and cost needs, marking a significant point in the evolution of computing.

• DEC PDP-8: Mini-computer, commercially successful and affordable, impacting the computing market.

Later Generations

• Advancements in LSI, VLSI, and ULSI continue, increasing component density on a chip, and leading to more complex and powerful systems.
• Semiconductor memory evolved, becoming faster, cheaper, and more crucial part of modern computers.
• Introduction of microprocessors, combining central processing unit components onto a single chip.