Computer Organization: Input Devices

Introduction to Computer Organization

• Computer organization deals with the hardware and software components of a computer system

Input Devices

• Keyboard:
  • Types: 84 keys, 101/102 keys, 104 keys, 108 keys
  • Functions: typing keys, numeric keypad, function keys, control keys, special purpose keys
• Mouse:
  • Pointing device
  • Used for selecting items on the screen
• Joystick:
  • Pointing device
  • Used in computer-aided designing (CAD) and playing computer games
• Light Pen:
  • Pointing device
  • Used to select menu items or draw on the screen
• Scanner:
  • Input device
  • Works like a photocopy machine
• Microphone:
  • Input device
  • Input sound, stored in digital form
• Magnetic Ink Card Reader (MICR):
  • Input device
  • Used in banking to process large number of cheques
• Optical Character Reader (OCR):
  • Input device
  • Reads printed text, converts to machine-readable code, stores in system memory
• Bar Code Reader:
  • Input device
  • Reads bar coded data

Output Devices

• Monitors:
  • Types: Cathode-Ray Tube (CRT), Flat-Panel Display Monitor
  • Characteristics of CRT: large in size, high power consumption
  • Characteristics of Flat-Panel Display Monitor: reduced volume, weight, and power requirement
• Printers:
  • Types: Impact Printers, Non-Impact Printers
  • Impact Printers:
    • Characteristics: low consumable costs, noisy, useful for bulk printing
    • Types: Character Printers, Line Printers
  • Non-Impact Printers:
    • Types: Laser Printers, Inkjet Printers
  • Characteristics of Laser Printers: high speed, high quality output, good graphics quality
  • Characteristics of Inkjet Printers: high quality printing, reliable, expensive

System Unit Components

• Motherboard:
  • Primary device of the system unit
  • Connects all computer devices (video card, RAM, sound card, hard drive, etc.)
• Processor (CPU):
  • Performs billions of mathematical calculations per second
  • Consists of ALU, Memory Unit, and Control Unit
• RAM (Random Access Memory):
  • System memory
  • Connected directly to the motherboard
• Hard Drive:
  • Mechanical drive that works on magnetic recording
  • Central storage of data on most computers
• Video Card (Graphics Adapter):
  • Graphics accelerator
  • Generates and displays images
• Power Supply:
  • Converts electrical energy into direct current required by the computer

CPU Components

• ALU (Arithmetic Logic Unit):
  • Performs arithmetic and logic operations
• Memory Unit:
  • Stores instructions, data, and intermediate results
• Control Unit:
  • Controls the operation of all parts of the computer

Motherboard and Ports

• Motherboard:
  • Connects all parts of the computer together
  • Provides ports for connecting external devices
• Ports:
  • Types: Serial Port, Parallel Port, PS/2 Port, USB Port, VGA Port, Power Connector, Firewire Port, Modem Port, Ethernet Port, Game Port, DVI port
  • Characteristics of each port type