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

Types and Components of Computer Systems

Learning Objective

Know and understand the internal components of a computer system, with particular focus on the Central Processing Unit (CPU), processor, and motherboard.

1. Overview of Computer System Types

Computer systems can be classified according to size, purpose and architecture. The main categories are:

• Desktop computers – personal use, typically placed on a desk.
• Laptop/Notebook computers – portable, integrated display and keyboard.
• Tablet computers – touch‑screen devices, often running mobile operating systems.
• Servers – provide services to other computers over a network.
• Embedded systems – specialised computers built into appliances, vehicles, etc.

2. Internal Components

The internal hardware that makes a computer work can be grouped into three core areas:

1. Processing unit (CPU and processor)
2. Memory and storage
3. Support circuitry (motherboard and related chips)

2.1 Central Processing Unit (CPU)

The CPU is often described as the “brain” of the computer. It performs three fundamental operations:

• Fetch – retrieving an instruction from memory.
• Decode – interpreting the instruction.
• Execute – performing the operation and storing the result.

Key characteristics of a CPU include:

2.2 Processor vs. CPU

In everyday language the terms “processor” and “CPU” are used interchangeably, but technically:

• The CPU refers specifically to the core(s) that execute instructions.
• The processor can include the CPU plus integrated components such as graphics processing units (GPUs), memory controllers, and I/O interfaces, especially in system‑on‑chip (SoC) designs.

2.3 Motherboard

The motherboard (also called the mainboard or system board) is the primary printed circuit board (PCB) that interconnects all components. Its main functions are:

• Providing physical slots and sockets for CPU, RAM, storage, and expansion cards.
• Distributing power from the power supply to each component.
• Facilitating communication via buses (e.g., system bus, PCIe, USB).

Important sections of a motherboard include:

3. How the Components Work Together

When a computer is powered on, the following sequence occurs:

1. The power supply sends stable voltages to the motherboard.
2. The motherboard’s BIOS/UEFI performs a POST (Power‑On Self Test).
3. The CPU begins executing firmware instructions, which initialise hardware and load the operating system from storage into RAM.
4. Once the OS is running, the CPU continuously fetches, decodes, and executes user and system instructions, using RAM for temporary data and the motherboard’s buses to communicate with peripherals.

4. Revision Checklist

• Define the CPU and list its three basic operations.
• Explain the difference between a CPU and a processor.
• Identify at least six key parts of a motherboard and their functions.
• Describe how the CPU, RAM, and motherboard interact during normal operation.

5. 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 contacts must align; otherwise the CPU cannot be seated.
2. Electrical compatibility – voltage and signalling standards differ; mismatched sockets can prevent the CPU from receiving correct power or data.
3. Consequences: the computer will not boot, and attempting to force the CPU into an incorrect socket may damage both the processor and the motherboard.