Introduction to Computers

CHAPTER 1: INTRODUCTION TO COMPUTERS

What is a Computer?

  • Definition:

    • A computer is defined as a machine that manipulates data according to a list of instructions.

    • It is capable of performing computations and making logical decisions at speeds millions and even billions of times faster than human beings.

    • It is an electronic machine utilized for data processing; the output after processing data through a computer is referred to as Information.

History of Computers:

  • The evolution of computers is categorized into five generations:

    1. Zeroth Generation (1642 to 1945)

    2. First Generation (1945 to 1955)

    3. Second Generation (1955 to 1965)

    4. Third Generation (1966 to 1970)

    5. Fourth Generation (1971 to 1980)

    6. Fifth Generation (1980 to present)

Zeroth Generation (1642 - 1945)

  • Mechanical calculators were developed as computing devices during this period.

First Generation (1945 - 1955)

  • Notable Development:

    • In 1946, the first electronic computer named ENIAC (Electronic Numerical Integrator and Calculator) was developed by Mr. J. Presper Eckert and Mr. John Mauchly at the University of Pennsylvania.

  • Specifications:

    • Components: Utilized 18,000 vacuum tubes.

    • Cost: $500,000.

    • Weight: Approximately 30 tons.

    • Physical Space: Occupied a space measuring 30 by 50 feet.

    • Heat Production: Produced a significant amount of heat.

    • Speed: Notably slow compared to modern standards.

Second Generation (1955 - 1965)

  • Technological Advancement:

    • Vacuum tubes were replaced by transistors during this generation.

  • Improvements:

    • Enhanced speed and performance of computers compared to first generation.

    • Reduction in size, cost, and heat production due to the use of transistors.

Third Generation (1966 - 1970)

  • Technological Advancement:

    • Transistors were replaced by Integrated Circuits (ICs), which involved the fabrication of thousands of electronic components on a single silicon chip.

  • Improvements:

    • Drastic reduction in the size of computers.

    • Higher speed and performance compared to the second generation.

    • Reduced heat production compared to previous generations.

Fourth Generation (1971 - 1980)

  • Technological Advancement:

    • Integrated Circuits (ICs) were replaced by Large Scale Integrated Circuits (LSI) during this generation.

  • Improvements:

    • Lower cost, smaller size, and higher performance compared to third generation computers.

Fifth Generation (1980 - Present)

  • Technological Advancement:

    • Large Scale Integrated Circuits (LSI) were succeeded by Very Large Scale Integrated Circuits (VLSI).

  • Improvements:

    • Significantly reduced size and cost of computers, while markedly increasing performance.

Categories of a Computer

  • A computer can be broadly categorized into two main components:

    1. Hardware

    • Refers to the physical components of a computer, anything that can be physically touched.

    • Examples of Hardware Components:

      • Computer Case

      • CPU (Central Processing Unit, e.g., Pentium chip)

      • Monitor

      • Keyboard & Mouse

      • Disk Drive, Zip Drive, CD-ROM, DVD, Hard Drive

      • Memory (RAM)

      • Speakers

      • Printer

    1. Software

    • In order for hardware to operate, it must follow a set of instructions provided as software.