Know and understand internal components including Central Processing Unit (CPU), processor, motherboard

Topic 1 – Types and Components of Computer Systems (IGCSE ICT 0417)

Learning Objective

Know and understand the internal and peripheral components of a computer system, the different types of computers, the role of the operating system, and the wider effects of using information technology.

1. Types of Computer Systems

2. Input and Output (I/O) Devices

Both input and output devices are essential for interaction with a computer. The syllabus expects you to describe their characteristics, uses, advantages and disadvantages.

3. Storage Devices & Media

Distinguish between primary (volatile) and secondary (non‑volatile) storage, and be able to compare the main types of media.

4. Networks and the Effects of Using ICT

Understanding basic network concepts and the positive/negative effects of information technology is essential for the exam.

• Network Types

  • LAN (Local Area Network) – limited to a building or campus; uses Ethernet or Wi‑Fi.
  • WAN (Wide Area Network) – covers larger geographic areas; the Internet is the biggest WAN.
  • Wireless networks – Wi‑Fi, Bluetooth, NFC; enable mobility but can be less secure.

• Positive Effects of ICT

  • Improved communication (email, video‑conferencing)
  • Access to information and learning resources
  • Increased productivity through automation
  • Support for remote work and collaboration

• Negative Effects of ICT

  • Health issues (eye strain, repetitive‑strain injuries)
  • Security risks (malware, data loss, hacking)
  • Social concerns (digital divide, cyber‑bullying, reduced face‑to‑face interaction)
  • Environmental impact (e‑waste, energy consumption)

5. Core Internal Components

The hardware inside any computer can be grouped into four inter‑related areas.

1. Processing Unit – CPU, processor, and (if present) integrated GPU.
2. Primary Memory – RAM (volatile) and ROM/firmware (non‑volatile).
3. Secondary Storage – HDD, SSD, optical drives, removable media.
4. Support Circuitry – Motherboard, chipset, power delivery, buses and connectors.

5.1 Central Processing Unit (CPU)

The CPU is the “brain” of the computer. It carries out the fetch – decode – execute cycle for every instruction.

• Control Unit (CU) – directs the operation of the processor, fetching instructions from memory and generating control signals.
• Arithmetic‑Logic Unit (ALU) – performs arithmetic (addition, subtraction…) and logical (AND, OR, NOT…) operations.
• Registers – ultra‑fast storage locations inside the CPU used for immediate data manipulation.

5.2 Processor vs. CPU

• CPU – the core(s) that execute instructions.
• Processor – a broader term that may include the CPU plus tightly integrated components such as:

  • Graphics Processing Unit (GPU)
  • Memory controller
  • I/O interfaces (USB, PCIe, etc.)
  • Specialised accelerators (AI, video encoding)

Examples:

• Desktop CPU – Intel Core i7‑12700K (separate CPU, separate graphics card).
• Mobile SoC – Apple A16 Bionic (CPU cores, GPU, neural engine and memory controller on one chip).

5.3 Motherboard (Mainboard / System Board)

The motherboard is the central printed circuit board that interconnects all components and supplies power.

5.4 Primary Memory – RAM & ROM

• Random‑Access Memory (RAM) – volatile, fast memory where the CPU stores data and program code while running. Measured in gigabytes (GB). Common types: DDR4, DDR5.
• Read‑Only Memory (ROM) / Firmware – non‑volatile memory that stores the BIOS/UEFI and other low‑level code. Cannot be altered by normal software.

5.5 Secondary (Backing) Storage

See the detailed table in Section 3 for a comparison of the main storage technologies.

5.6 Essential Internal & External I/O Devices

• Graphics Card (GPU) – renders images for the monitor; may be integrated or discrete.
• Sound Card – processes audio; often integrated on modern motherboards.
• Network Interface Card (NIC) – provides Ethernet or Wi‑Fi connectivity.
• Keyboard & Mouse – primary human‑computer interaction devices.
• Monitor / Display – visual output; resolution and refresh rate affect user experience.
• Printer, Scanner, External Speakers – peripheral devices that extend functionality.

6. Operating System (OS) – Linking Hardware and Software

The OS manages the hardware resources described above and provides a user interface.

Key OS functions related to hardware

• CPU scheduling – decides which program gets processor time.
• Memory management – allocates RAM and handles paging to storage.
• Device drivers – translate OS requests into hardware actions (graphics, network, printer, etc.).
• File system – organises data on secondary storage.

7. How the Components Work Together – Boot Sequence

1. Power‑On – The power supply delivers 12 V, 5 V and 3.3 V to the motherboard.
2. POST (Power‑On Self Test) – BIOS/UEFI checks CPU, RAM, graphics and essential peripherals.
3. Bootstrap Loader – Firmware reads the first sector of the boot device (usually an SSD/HDD) and loads the OS kernel into RAM.
4. OS Initialisation – The OS configures drivers, sets up virtual memory and presents the login screen.
5. Normal Operation – The CPU repeatedly fetches, decodes and executes instructions, using RAM for active data and the motherboard’s buses (system bus, PCIe, USB, etc.) to communicate with storage, graphics, network and peripheral devices.

8. Emerging Technologies and Future Trends

• AI Accelerators – Dedicated cores (e.g., Tensor Processing Units) embedded in CPUs or offered as separate cards to speed up machine‑learning tasks.
• XR‑Ready GPUs – High‑performance graphics and low‑latency displays for augmented/virtual reality.
• NVMe over PCIe – Faster storage interfaces becoming standard in desktops and laptops.
• Edge Computing Devices – Small, powerful SoCs placed in embedded systems to process data locally rather than in the cloud.

9. Revision Checklist

• Define the CPU and describe the roles of the Control Unit, ALU and registers.
• List and explain the four key CPU characteristics: clock speed, core count, cache, instruction set.
• Distinguish between “CPU” and “processor” with real‑world examples.
• Identify at least eight major parts of a motherboard and state their functions.
• Compare RAM and ROM – purpose, volatility, typical capacities.
• Name the main types of secondary storage and their advantages/disadvantages.
• State the purpose of a graphics card, sound card and network interface card.
• Outline the boot sequence from power‑on to operating system ready.
• Summarise the four OS interface types and give an example of each.
• Explain two ways emerging technologies are influencing hardware design.
• List three positive and three negative effects of using ICT.
• Describe the main types of input and output devices, including at least one advantage and one disadvantage for each.
• Identify the three main network types (LAN, WAN, Wireless) and give a typical use for each.

10. Sample Exam Question

Question: A student is assembling a desktop computer. Explain why it is essential to match the CPU socket type on the motherboard with the processor being installed, and describe two consequences of using an incompatible combination.

Answer (key points):

1. Physical compatibility – The pins (or pads) on the CPU must line up with the socket’s contacts; otherwise the processor cannot be seated securely.
2. Electrical compatibility – Different socket families support different voltage levels, signalling standards and instruction sets. A mismatch can prevent the CPU from receiving correct power or data.
3. Consequences:

   • The computer will fail to POST and will not boot.
   • Forcing an incompatible CPU into the socket may damage the processor pins and the motherboard’s socket contacts, leading to costly repairs.

11. Quick Reference Diagram (Suggested)