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I.11 Types of Hardware

⬆️ Back to: P-I.I. Introduction to Computing

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Page Outline — click a heading to jump. Past-paper questions sit in the last section.

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Exam pattern (2016–2026): 2024 MCQs Q1 (USB port), Q2 (OLED monitor), Q3 (PSU). All three came in one paper.

1. Definition

  • Hardware: any physical part of a computer that can be seen and touched.

2. Five Functional Categories

CategoryRoleExamples
InputFeeds data and commands inKeyboard, mouse, scanner, microphone
OutputShows resultsMonitor, printer, speaker, plotter
ProcessingExecutes instructionsCPU, GPU, motherboard chipset
StorageHolds data and programsRAM, ROM, HDD, SSD
CommunicationExchanges data with networksModem, NIC, router, switch
  • Use this five-way split for any essay on "hardware components".
  • Details: I.7 Input, I.8 Output, I.9 Storage, I.5 Components.

3. Other Classification Axes

  • By location:
    • Internal: CPU, RAM, motherboard, internal drive, PSU.
    • Peripheral: keyboard, mouse, monitor, printer, external drives.
  • By necessity:
    • Essential: CPU, RAM, motherboard, PSU, boot drive.
    • Optional: printer, scanner, speakers, webcam.
  • Tip: say which axis you are using before you classify.

4. Processing Hardware

4.1 CPU

  • ALU: calculations and logic; sets flags (zero, carry, overflow, negative).
  • Control Unit: runs fetch → decode → execute; computes nothing.
  • Registers: fastest memory, inside the chip (ACC, PC, IR, MAR/MDR).
  • Clock speed: GHz (3.5 GHz = 3.5 billion cycles per second).
  • Cores: independent units on one chip → parallel work.

4.2 Motherboard

  • Main circuit board that connects every part.
  • Does not process — it connects and coordinates.
  • Provides: buses, power distribution, chipset, BIOS/UEFI ROM, CMOS battery.
  • Connected to it:
    • CPU (socket)
    • RAM (DIMM slots)
    • Expansion cards (PCIe)
    • Drives (SATA, M.2/NVMe)
    • Ports (USB, HDMI, audio, RJ-45)
    • PSU (24-pin ATX)

4.3 Power Supply Unit (PSU)

  • Converts mains AC to low-voltage DC and feeds every component.

5. Communication Hardware

5.1 Modem

  • Modulates digital data onto a line signal and demodulates it back.
  • Why needed for phone lines:
    • Computers send square-wave digital pulses.
    • Phone lines (PSTN) carry only voice-band analogue signals (about 300–3,400 Hz).
    • Modem encodes bits as tones (ASK, FSK, PSK, QAM) — the dial-up "screech".
    • Ceiling about 56 kbps (V.90/V.92).
  • Today: DSL, cable and fibre modems do the same job at hundreds of Mbps.
  • CSS angle: PTCL dial-up (late 1990s) → DSL, 3G/4G, fibre under PTA.

5.2 Network Interface Card (NIC)

  • Connects one computer to a network.
  • Wired (Ethernet, RJ-45) or wireless (Wi-Fi).
  • Has a unique 48-bit MAC address; works at OSI Layer 2.

5.3 Router

  • Forwards packets between networks (LAN ↔ Internet).
  • Uses IP addresses and a routing table; OSI Layer 3.
  • Home router = router + switch + Wi-Fi access point (+ often a modem).

5.4 NIC vs Router

AspectNICRouter
RoleConnects one computerLinks networks
ScopeSingle hostMany hosts
Address usedMACIP
OSI layer2 (Data Link)3 (Network)
LocationInside or on the PCSeparate box at network edge

6. ⚠️ MCQ Traps

  • Communication hardware is the category students forget.
  • Modem converts signals; router directs traffic.
  • Location and necessity are separate axes (external SSD can be essential; a second internal drive can be optional).
  • CPU processes; motherboard only connects.

7. ✅ Self-Test Questions (with Answers)

Q1. List the five functional categories of hardware.

  • Input, output, processing, storage, communication — with examples from section 2.

Q2. What does a modem do, and why was it needed for phone-line Internet?

  • Converts digital ↔ line signal.
  • Phone lines were built for analogue voice; raw digital pulses would be distorted.
  • See 5.1.

Q3. NIC vs router?

  • NIC joins one machine (MAC, Layer 2); router links networks (IP, Layer 3).
  • Use the table in 5.4.

Q4. Classify keyboard, internal SSD, printer on three axes.

DeviceFunctionLocationNecessity
KeyboardInputPeripheralEssential in practice (a headless server runs without one)
Internal SSDStorageInternalEssential (holds the OS)
PrinterOutputPeripheralOptional

Q5. Three sub-parts of a CPU?

  • ALU (computes), Control Unit (directs), registers (hold current data).

Q6. Role of the motherboard and two things connected to it?

  • Connects and powers all parts; does not process.
  • Any two: CPU, RAM, PCIe cards, SATA/M.2 drives, USB/HDMI ports, PSU.

8. 📜 Past-Paper Questions & MCQs (CSS 2016–2026)

MCQs

2024 P-I · Q1. Which of the following ports is used to connect external devices such as printers, scanners and cameras to a computer?

  • (A) USB (Universal Serial Bus) ✅
  • (B) HDMI (High-Definition Multimedia Interface)
  • (C) VGA (Video Graphics Array)
  • (D) None of these
  • Answer: (A) USB.
  • Why: USB is the general-purpose peripheral port. HDMI carries audio and video to a display; VGA carries only analogue video.

2024 P-I · Q2. Which type of monitor technology offers the widest viewing angles and accurate colour reproduction?

  • (A) CRT (Cathode Ray Tube)
  • (B) OLED (Organic Light-Emitting Diode) ✅
  • (C) LCD (Liquid Crystal Display)
  • (D) None of these
  • Answer: (B) OLED.
  • Why: each OLED pixel makes its own light, so colour holds from the side and blacks are true. LCD colours shift off-angle; CRT is bulky with weaker colour.

2024 P-I · Q3. Which component is responsible for providing power to all the other components in a computer system?

  • (A) Power Supply Unit (PSU) ✅
  • (B) Central Processing Unit (CPU)
  • (C) Motherboard
  • (D) None of these
  • Answer: (A) PSU.
  • Why: the PSU turns mains AC into DC and distributes it. The CPU processes; the motherboard connects but does not generate power.