Types of Peripheral Devices

• Input devices let a user get data or commands INTO a computer system (keyboard, mouse, scanner, biometric scanner, sensors, etc.)
• Output devices let a computer send processed results OUT to the user in a form they can understand (monitors, printers, speakers, actuators)
• Storage devices are the physical hardware that reads/writes data — split into three families: Magnetic, Solid State, and Optical
• Storage media is the actual "stuff" data is stored on (hard disks, CDs/DVDs/Blu-rays, flash memory, magnetic tape) — media and devices must be paired correctly
• Capacity of storage is measured using binary-based units: bit → nibble → byte → kibibyte → mebibyte → gibibyte → tebibyte, each one 2¹⁰ (1024×) bigger than the last
• You need to be able to explain advantages, disadvantages, and appropriate uses of each device — not just name them

What is an input device?

Think of a computer system as a brain in a sealed box — it has no eyes, ears, or hands of its own. An input device is any piece of hardware that acts as that missing sense: it lets a human (or the environment) push data or commands into the system so the processor has something to work with.

Why does the exam board split them into categories?

Not all input devices work the same way. Some are "direct entry" (you type or click), some "convert physical marks into digital data" (scanners, OMR, OCR), some "read a code" (barcode, RFID, magnetic stripe), and some "sense the environment automatically" (sensors, biometric scanners). Spotting which category a device belongs to is often the key to answering "why is this device suitable for X situation?" questions.

Direct entry & pointing devices