Computer Organization: Input Devices

Study Notes

Keyboard: an input device that helps input data to the computer, available in various sizes (84, 101/102, 104, 108 keys).
Types of keys on a keyboard:
- Typing keys (A-Z, 0-9)
- Numeric keypad (17 keys, used for numeric data and cursor movement)
- Function keys (12 keys, each with a unique meaning and purpose)
- Control keys (cursor and screen control, including arrow keys, Home, End, Insert, Delete, etc.)
- Special purpose keys (Enter, Shift, Caps Lock, Num Lock, Space bar, Tab, Print Screen)
Other input devices:
- Mouse: a popular pointing device
- Joystick: a pointing device used in Computer Aided Designing (CAD) and gaming
- Light pen: a pointing device used to select menu items or draw on the monitor screen
- Scanner: an input device that works like a photocopy machine
- Microphone: an input device that converts sound into digital form
- Magnetic Ink Card Reader (MICR): an input device used in banks to process large numbers of cheques
- Optical Character Reader (OCR): an input device that reads printed text and converts it into machine-readable code
- Bar Code Readers: a device used to read bar-coded data

Monitors:
- Cathode-Ray Tube (CRT) display: made up of small pixels, with smaller pixels resulting in better image clarity
- Disadvantages of CRT: large in size, high power consumption
- Flat-Panel Display Monitor: a class of video devices with reduced volume, weight, and power requirement
Printers:
- Types of printers: Impact Printers, Non-Impact Printers
- Impact Printers:
  - Print characters by striking them on the ribbon, which is then pressed on the paper
  - Characteristics: low consumable costs, noisy, useful for bulk printing, physical contact with paper to produce an image
  - Types: Character printers, Line printers
- Character Printers:
  - Print one character at a time
  - Types: Dot Matrix Printer (DMP), Daisy Wheel
  - Dot Matrix Printer: popular due to ease of printing and economical price, each character printed in a dot matrix format