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Computer Architecture

Historical Evolution

Learn about the evolution of computers from early calculating machines to modern processors.

Core Components

Understand CPU, memory, buses, and I/O units that make up computer systems.

Memory Hierarchy

Explore different types of memory and their roles in computer systems.

Architecture Types

Compare von Neumann and Harvard architectures and their applications.

1. Historical Introduction

Early Computing Devices

  • The abacus (circa 2000 BC) from ancient Mesopotamia
  • The quipu system based on knots and strings
  • 17th century mechanical calculators:
    • Pascal’s Calculator (1642)
    • Leibniz Wheel (1672)

Evolution of Calculating Machines

  • Arithmometer (1820)
  • Curta Calculator (1948)
  • Spanish Minerva Calculator (1945)

2. Computer Generations

  1. First Generation (1945-1955)

    • Based on vacuum tubes
    • ENIAC and EDVAC computers
    • von Neumann architecture introduction

  2. Second Generation (1955-1965)

    • Transistor-based computers
    • IBM 650 and 702 models
    • Room-sized computers weighing about 1 ton

  3. Third Generation (1965-1975)

    • Integrated circuits
    • IBM S/360 and S/370
    • First storage devices (tapes and early hard drives)

  4. Fourth Generation (1975-1985)

    • Microchips with thousands of transistors
    • Personal computers emerge
    • Apple I, II, and early IBM PCs

  5. Fifth Generation (1985-Present)

    • Advanced microprocessors
    • Multi-core processing
    • Miniaturization and standardization

3. Von Neumann Architecture

The von Neumann architecture consists of these main components:

CPU

  • Control Unit (CU)
  • Arithmetic Logic Unit (ALU)
  • Registers

Memory

  • Main memory for instructions and data
  • Memory addressing system

I/O

  • Input/Output units
  • Peripheral management

Buses

  • Data bus
  • Address bus
  • Control bus

4. Harvard Architecture

The Harvard Architecture differs by having:

  • Separate memories for instructions and data
  • Different buses for each memory type
  • Capability for simultaneous instruction and data access

5. Memory Hierarchy

CPU Registers

  • Fastest access (1-2ns)
  • Very small capacity (1-32 bytes)

Cache Memory

  • L1, L2, L3 Cache
  • Access time: 5-50ns
  • Capacity: KB to MB range

Main Memory

  • RAM
  • Access time: 25-100ns
  • Capacity: GB range

Secondary Storage

  • HDDs and SSDs
  • Access time: 5-20ms
  • Capacity: TB range

Additional Resources

Learn More

Check our detailed guides on specific computer architecture topics.

Practice

Try our interactive simulations and exercises.