In-Depth Notes on Computer Organisation and Architecture

Key Concepts in Computer Science

  • System Design: Arrangement of computer systems to function together.

  • Computer Organisation: Layout of operational units and connections.

  • Networks: Interconnected systems for data exchange.

  • Computational Thinking: Problem-solving using computer science techniques.

  • Abstract Data Structures: Data organization for efficiency.

  • Resource Management: Allocation strategies for computer resources.

  • Control: Management of operations in computer systems.

Overview of Computer Architecture (2.1.1)

  • Central Processing Unit (CPU): Executes instructions from memory.

    • Arithmetic Logic Unit (ALU): Handles arithmetic and logical operations.

    • Control Unit (CU): Manages data flow within the CPU.

    • Registers: Fast storage for temporary data.

  • Memory Types:

    • Primary Memory: Fast access memory (e.g., RAM, ROM).

    • RAM: Volatile; temporarily stores data.

    • ROM: Non-volatile; permanently stores essential programs.

    • Cache Memory: Quick access memory for frequently used data.

    • Machine Instruction Cycle: Fetches, decodes, and executes instructions.

Persistent Storage (2.1.5)

  • Importance: Saves data long-term when devices are powered off.

Operating Systems and Applications (2.1.6)

  • Functions of an Operating System: Manages resources and provides services.

  • Application Software: Programs for specific user tasks (e.g., word processing).

Binary Representation (2.1.9)

  • Basic Terms:

    • Bit: Smallest data unit (0 or 1).

    • Byte: 8 bits.

    • Binary: Base 2 number system.

    • Decimal: Base 10 number system.

    • Hexadecimal: Base 16 number system for compact data representation.

Logic Gates (2.1.11)

  • Boolean Operators:

    • AND: true if both inputs are true.

    • OR: true if at least one input is true.

    • NOT: inverts the input.

    • NAND, NOR, XOR: Additional gate functions.

CPU Functions

  • ALU Functions: Arithmetic and logical operations.

  • CU Functions: Loads, decodes commands, and directs ALU operations.

Execution Cycle**

  • Programs execute from secondary storage into RAM.

Memory Components

  • Registers: Fast storage for immediate data access.

    • MAR: Memory Address Register.

    • MDR: Memory Data Register.

Buses in Computer Architecture

  • Buses: Communication pathways between CPU and components.

    • Data Bus: Transfers data.

    • Control Bus: Sends control signals.

    • Memory Bus: Connects CPU to RAM through MAR.