I/O Devices
Introduction to Input & Output Devices
Input and Output (I/O) devices are the hardware components that allow humans to communicate with computers. Input devices send data into the processor, while output devices present the processed information back to the user in a readable format.
Classification: The Direction of Data
- Input Devices: Capture data or commands from the user (Keyboard, Mouse, Scanner).
- Output Devices: Translate processed data into a human-understandable form (Monitor, Printer, Speakers).
- Dual-Purpose Devices: Perform both input and output functions (Touchscreens, Modems, Headsets).
The I/O Devices Master Table
| Device | Category | Specific Technology / Metric | Key Usage |
|---|---|---|---|
| Keyboard | Input | QWERTY Layout | Text entry |
| Mouse | Input | Optical / Wireless | Pointing & Selecting |
| Scanner | Input | OCR (Optical Char. Recognition) | Digitizing documents |
| Monitor | Output | Pixels / Resolution | Visual display |
| Laser Printer | Output | Non-impact / Toner | High-quality printing |
| Plotter | Output | Vector Graphics (Pens) | Blueprints & Posters |
| MICR | Input | Magnetic Ink Recognition | Bank Cheque processing |
| OMR | Input | Optical Mark Recognition | Grading MCQ sheets |
Key Scientific Facts
- Douglas Engelbart invented the first computer mouse in 1964, which was made of wood.
- DPI (Dots Per Inch) is the metric used to measure the resolution and quality of a printer's output.
- PPM (Pages Per Minute) is the standard unit for measuring the speed of a printer.
- Impact Printers (like Dot Matrix) physically strike a ribbon to transfer ink, while Non-Impact Printers (like Laser or Inkjet) use heat or sprays.
- VDU (Visual Display Unit) is another name for a computer monitor.
Subject Card Prompts (Flashcards)
- Q: Which device is used in banks to read the special numbers at the bottom of cheques?
- A: MICR (Magnetic Ink Character Recognition).
- Q: What is the primary output device of a computer?
- A: Monitor (VDU).
- Q: Is a Touchscreen an input or an output device?
- A: Both (Dual-purpose).
- Q: Which printer uses toner powder instead of liquid ink?
- A: Laser Printer.
Practice MCQ
"Which of the following is an output device used for producing high-quality large-scale drawings, such as architectural blueprints?"
A) Scanner
B) Inkjet Printer
C) Plotter
D) OMR
(Correct: C - Plotter)