Know and understand hardware as the physical components of a computer system

Published by Patrick Mutisya · 14 days ago

ICT 0417 – Types and Components of Computer Systems

1. Types and Components of Computer Systems

Objective

Know and understand hardware as the physical components of a computer system.

1.1 What is Hardware?

Hardware refers to all the tangible, physical parts of a computer system that you can touch, such as chips, circuit boards, cables, and peripheral devices. These components work together to process data, store information, and enable communication with users and other devices.

1.2 Major Types of Computer Systems

Computer systems are classified according to their size, purpose, and performance capabilities.

  • Personal Computers (PCs) – Desktop or laptop computers used by individuals for everyday tasks.

  • Servers – Machines that provide resources, services, or data to other computers over a network.

  • Mainframes – Large, powerful systems used by organisations for bulk data processing, such as banking.

  • Supercomputers – Extremely fast computers used for scientific simulations, weather forecasting, and complex calculations.

  • Embedded Systems – Dedicated computers built into other devices (e.g., washing machines, automotive control units).

  • Mobile Devices – Smartphones and tablets that combine computing power with portability.

1.3 Core Hardware Components

The hardware of any computer system can be grouped into five functional categories.

CategoryKey ComponentsPrimary Function
Processing UnitCPU (Central Processing Unit), GPU (Graphics Processing Unit)Executes instructions, performs calculations, controls other components.
MemoryRAM (Random‑Access Memory), ROM (Read‑Only Memory), CacheStores data temporarily for fast access (RAM) and permanently for firmware (ROM).
StorageHard Disk Drive (HDD), Solid‑State Drive (SSD), Optical drives, Flash drivesRetains data and programs when power is off.
Input DevicesKeyboard, Mouse, Touchscreen, Scanner, MicrophoneConvert user actions or analog signals into digital data.
Output DevicesMonitor, Printer, Speakers, ProjectorPresent processed information to the user in visual, printed, or audio form.
Support ComponentsMotherboard, Power Supply Unit (PSU), Cooling system (fans, heat sinks), Expansion cardsProvide connectivity, power, and thermal management for all other components.

1.4 Detailed Look at Key Components

1.4.1 Central Processing Unit (CPU)

The CPU is often called the "brain" of the computer. It fetches, decodes, and executes instructions stored in memory. Modern CPUs contain multiple cores, allowing parallel processing of tasks.

1.4.2 Memory (RAM & ROM)

RAM provides fast, temporary storage for data that the CPU needs while running programs. ROM holds firmware such as the BIOS/UEFI, which initiates the boot process.

1.4.3 Storage Devices

HDDs store data magnetically on rotating platters, while SSDs use flash memory with no moving parts, offering faster access times and greater durability.

1.4.4 Motherboard

The motherboard is a large printed circuit board that interconnects all components via buses and slots. It houses the chipset, which manages data flow between the CPU, memory, and peripherals.

1.4.5 Power Supply Unit (PSU)

The PSU converts mains AC voltage to the low‑voltage DC required by the computer’s components (commonly +12 V, +5 V, and +3.3 V). It also provides protection against voltage spikes.

1.4.6 Cooling System

Heat generated by the CPU, GPU, and other components must be dissipated to maintain performance and reliability. Cooling is achieved using fans, heat sinks, and, in high‑performance systems, liquid cooling loops.

1.5 How Components Interact – A Simple Data Flow

When a user types on a keyboard, the following sequence occurs:

  1. The keyboard (input device) converts the keystroke into a digital signal.

  2. The signal travels via the motherboard’s bus to the CPU.

  3. The CPU processes the instruction, possibly retrieving data from RAM.

  4. If the result needs to be stored, it is written to a storage device (HDD/SSD).

  5. The final output (e.g., a character on the screen) is sent to the monitor (output device) through the graphics subsystem.

1.6 Suggested Diagram

Suggested diagram: Block diagram showing the relationship between CPU, memory, storage, input devices, output devices, and the motherboard.

1.7 Quick Revision Checklist

  • Identify the five functional categories of hardware.

  • Explain the role of the CPU, RAM, and storage devices.

  • List at least three types of computer systems and their typical uses.

  • Describe how the motherboard connects all components.

  • Understand why cooling and power supply are essential for hardware reliability.