Lecture Notes: Introduction to Computers and Computer Organization

Introduction to Computers

  • Definition of a Computer: A device capable of performing computations and making logical decisions faster than humans.

Categorization of Computers by Performance and Purpose

  • Supercomputer:

  • Definition: Offers high-speed processing for complex calculations.

  • Example: IBM-built Sierra supercomputer.

  • Applications: Weather forecasting, air traffic control, aerospace development.

  • General-Purpose Computer:

  • Definition: Designed for both office and scientific calculations; includes mainframes.

  • Applications: Train seat reservations, online banking systems.

  • Office Computer:

  • Definition: Specialized computer (business server) designed for office processing.

  • Applications: Inventory control, sales management.

  • Workstation:

  • Definition: High-performance computer for specialized work connected to LANs and used as servers.

  • Applications: Software development, CAD/CAM.

Basic Computer Organization

  • Central Processing Unit (CPU): The brain of the computer.
  • Storage Unit: Where data and information are stored.
  • Input Unit: Receives instructions and data for processing.
Input Devices
  1. Keyboard: Standard device for text input.
  2. Mouse: Pointing device for navigating UI.
  3. Trackball: Ball rotated to move pointer.
  4. Trackpad: Moves pointer via finger movement on a flat surface.
  5. Pointing Stick: Controls pointer by applying pressure on a stick protruding from the keyboard.
  6. Digitizer/Tablets: Input device for design plans.
  7. Touch Panel/Screen: Inputs data through touch.
  8. Image Scanner: Captures photos and documents as digital data.
  9. Digital Camera: Captures images as digital data.
  10. Barcode Reader: Reads barcodes for data input.
  11. Optical Character Reader (OCR): Reads printed and handwritten text.
  12. Sound Input Device: Inputs voice data via microphone.
  13. Magnetic Card Reader: Reads data from magnetic stripe cards.
Output Devices
  • CRT Display: Traditional display using Cathode Ray Tube.
  • LCD Display: Uses liquid crystals to show images.
  • OLED Display: Emits light through organic molecules.
  • Laser Printer: Uses laser to print quickly and with quality.
  • Inkjet Printer: Sprays ink for color printing.
  • Dot Impact Printer: Uses pins to print characters.
  • Thermal Transfer Printer: Uses heat to transfer ink.
Memory Unit
  • Primary Storage Unit: Immediate storage for active data and instructions.
  • Random Access Memory (RAM): Volatile memory that loses data when power is off.
  • Types: SRAM (Static) and DRAM (Dynamic).
  • Read Only Memory (ROM): Non-volatile memory with persistent data.
  • Types:
    • Mask ROM: Prewritten data.
    • EPROM: Erasable with UV light.
    • EEPROM: Electrically erasable; used in flash memory.
Central Processing Unit Details
  • Arithmetic and Logic Unit (ALU): Handles arithmetic operations and logical decisions.
  • Control Unit (CU): Directs operations and manages data flow between components.

Number Systems

  • Common Number Systems:
  • Binary (0 & 1)
  • Octal (0-7)
  • Decimal (0-9)
  • Hexadecimal (0-9, A-F)
Radix Conversion
  • Converting between number systems (e.g., binary to decimal, decimal to octal).
  • Examples of conversions and exercises provided for practice.

Application Software and the Internet

  • Definition of Application Software: Software designed for specific tasks.
  • Types of Application Software:
  • Word Processing Software: Create and edit documents.
  • Spreadsheet Software: Perform calculations and visualize data.
  • Database Software: Manage and apply data.
  • Graphics Software: Edit images and drawings.
  • Presentation Software: Create visual presentations.
  • World Wide Web (WWW): Service for viewing and searching information online.
URL Components
  • Components of a URL include:
  • Scheme
  • Subdomain
  • Second-Level Domain
  • Top-Level Domain
  • Subdirectory
Search Engines
  • Used to find web pages when URLs are unknown by entering keywords.