Input and Output Devices
Hardware
A common exam question gives a scenario and asks which device best fits. The factors to consider:
- What is the task? Typing → keyboard. Drawing → graphics tablet. Pointing → mouse or touch screen. Capturing an image → camera or scanner. Producing printed pages → inkjet or laser printer. Producing a solid object → 3D printer.
- Who is the user? A small child may find a touch screen more intuitive than a keyboard. A visually impaired user may need a screen reader with speakers or headphones (output) and a Braille input device.
- Where is the device used? Outdoors → robust, weather-resistant. In a sterile environment (hospital, factory) → wipe-down or contactless. Public space → tamper-resistant.
- What is the budget? Inkjet printers are cheap to buy; laser printers are cheap to run for high volumes. Capacitive touch screens cost more than resistive but feel better. Trade off purchase cost against running cost and longevity.
Common exam question
Choosing an input or output device for a scenario
Question: Give or identify one or two appropriate input devices that would let a user or a system do a stated job, or an appropriate output device for a stated user (1–2 marks, one per device).
Asked in 2 of the 17 papers. Name a specific device that fits the job. For a library user entering a membership number at a self-checkout, the scheme credits a keyboard or keypad, touchscreen, mouse, microphone, digital camera, barcode scanner, QR code scanner or 2D scanner. For a system that reads train tickets automatically, the credited devices are a barcode scanner, QR code scanner or digital camera. For a blind user who cannot read a monitor, the output device is a speaker or headphones.
Match the device to the user: a machine checking tickets needs a code reader; a person entering a number can type, tap, scan or speak it; and a user who cannot see the screen needs sound.