Hardware components of a computer system

Hardware components are the physical components that constitute a computing system. They all are tangible objects, as opposed to software which is intangible. By contrast, software is instructions that can be stored and run by hardware.

Classroom Video: Inside A Computer (2008)

This program describes the roles of the computer in modern society, education and industry and how it fullfils those roles. It provides novice and experienced users, as well as budding technicians, an insight into the many aspects of a computer system, its design features and the function of various components. The way a computer processes information, something taken for granted among users, is looked at with a detailed description of the language used; formatting, input/output and storage.

Study Questions:

  1. What is a computer? Define.
  2. When did computers as we know them first appear? List the names of some of the first "personal computers".
  3. What did Microsoft produce to make computing accessible to almost anybody?
  4. Describe the main differences between Desktop, tablet and notebook(laptop) computers. What are some of their advantages and disadvantages?
  5. List the four main components of a computer system. What are the names of some other components that may be part of a computer?
  6. Why do we use input devices such as keyboards, mice and joysticks? What are some other input devices?
  7. What are output devices? List 3 output devices.
  8. Complete this sentence. To save work on a computer we can use ____ which are known as _____.
  9. Complete this statement. Every systems unit has a_____. Its role is _____.
  10. What does the system clock do?
  11. Name the two kinds of storage found in a computer. Give an example for each.
  12. Describe the function ports on a computer system. Provide 3 types of function ports.
  13. Which system does the CPU use to interpret and process input data? Explain why this is so.
    • A) Technical System
    • B) Binary System
    • C) Processing System
    • D) Javascript
  14. What acts as a kind of "translator" between people and the Binary System?
  15. What is one of the most important pieces of software currently in use all over the world? Why?

Inside a computer -

Have you ever looked inside a computer case, or seen pictures of the inside of one? The small parts may look complicated, but the inside of a computer case isn't really all that mysterious. This lesson will help you master some of the basic terminologyand understand a bit more about what goes on inside a computer.

Computer Basics: Inside a Desktop Computer


The motherboard is the main circuit board of the computer. It holds the crucial electronic components of the system including CPU and the memory. It also connects peripherals to the computer system such as sound cards, video cards, network cards, hard drives and TV tuner cards.

Hard disk drive (HDD)

A hard disk drive (HDD), hard disk, hard drive or fixed disk is a storage device that uses magnetic storage to store and retrieve digital information using one or more rigid rapidly rotating disks (platters) coated with magnetic material.

Central Processing Unit (CPU)

A central processing unit (CPU) is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions. It is essentially the 'brain' of the computer. Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.

Random Access Memory (RAM)

Random-access memory is a form of computer data storage which stores frequently used program instructions to increase the general speed of a system. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory. In contrast, with other direct-access data storage media such as hard disks, CD-RWs, DVD-RWs and the older drum memory, the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement.

Read Only Memory (ROM)

Read Only Memory, commonly known as the BIOS in the PC world, is a segment of memory that has been etched or burned with the code required to kickstart the CPU. Data stored in ROM can only be modified slowly, with difficulty, or not at all, so it is mainly used to store firmware (software that is closely tied to specific hardware, and unlikely to need frequent updates)

Expansion Cards

Expansion cards, (expansion boards, adapter cards or accessory cards), are a printed circuit board that can be inserted into an expansion slot on a computer motherboard to add functionality to a computer system via the expansion bus. The primary purpose of an expansion card is to provide or expand on features not offered by the motherboard. This can include network cards, sound cards, graphics cards, TV tuner cards and more.

Purpose of the central processing unit (CPU)

The Central Processing unit executes a computer program (makes the software work). Most computers execute only one instruction at a time. Instructions are executed quickly. Before an instruction is executed, the instructions and data are placed in primary storage.

  1. Fetch - The control unit fetches the instructions from primary storage
  2. Decode - The control unit decodes the instructions (works out what to do) and makes the data available to the arithmetic logic unit
  3. Perform operations - The arithmetic logic unit performs the operations on the data
  4. Store - The control unit places the result of the operation into primary storage or a register

What is a Core i3, Core i5, or Core i7 as Fast As Possible

Purpose of memory/storage

Types of memory/storage

Different Kinds of Memory as Fast As Possible

Primary storage

The primary storage in a computer is the RAM. The RAM is used for the running of software applications.

  • Temporary - The CPU uses the RAM in the Fetch --> Decode --> Perform Operations --> Store cycle. The instructions are loaded for the software to use and then discarded as new instructions are loaded in. Therefore, the computer only holds onto the information for a limited period of time, hence the name temporary storage.
  • Volatile - When a computer is switched on, data and instructions are being communicated to the Random access memory. Once the computer is switched off the RAM is cleared. This is referred to as volatile memory, meaning it will not be stored when there is no power supplied to it. This resets whatever bugs/ problems are temporarily saved in the RAM.

Secondary storage

The secondary storage in a computer is anywhere where data is saved for future use. Some examples include hard disk, USB flash drives, optical disks and memory cards.

  • Permanent - Storage holds data, instructions and information for future use. Software applications and users store information so it can be retrieved at a later date. The information is held permanently (or at least until the user decides it is no longer required).
  • Non-volatile - A computer can keep data, instructions and information on storage media. When a computer is switched off, applications and users want to be able to retrieve certain data once the computer is switched back on again.

Types of peripheral devices

Input devices

An input device is any hardware component that sends data to a computer, allowing you to interact with and control the computer. They are peripheral devices that allow the user to enter data and instructions into a computer.


  • Mouse
  • Keyboard
  • Microphone
  • Scanner
  • Webcam

Output devices

An output device is any hardware component that receives data from a computer, usually for display, projection, or physical reproduction. They are peripheral devices that convey information to one or more people.

  • Monitor
  • Printer
  • Speakers

Storage devices

Alternatively referred to as digital storage, storage, storage media, or storage medium, a storage device is any hardware component capable of holding information either temporarily or permanently.

Types of computer systems

Desktop systems

A desktop computer is a personal computer designed for regular use at a single location on or near a desk or table due to its size and power requirements.


  • Typically contain higher specifications than mobile devices
  • Do not require charging (permanent power source)
  • Easy to add extension cards
  • Easier to maintain


  • Tend to be bulky
  • Not meant to be moved frequently
  • Require permanent power source

Mobile devices

A small computing device designed to be portable or handheld.


  • Laptops
  • Mobile phones
  • Tablets


  • Lighter and smaller, can be carried around
  • Portable, are not required to be plugged in
  • Easily accessible to the user
  • Tend to be cheaper than PCs


  • Requires charging (no permanent power source)
  • Tend to have lower specifications than desktops (less room for specifications)
  • Can be more challenging to maintain than PCs


A computer which manages access to a centralised resource or service in a network. Servers can provide various functionalities, often called "services", such as sharing data or resources among multiple clients, or performing computation for a client. A single server can serve multiple clients, and a single client can use multiple servers. A client process may run on the same device or may connect over a network to a server on a different device. Any computer can be set up to be used as a server, but most dedicated servers in business networks are specialised for running services. This often implies that it is more powerful and reliable than standard personal computers, but alternatively, large computing clusters may be composed of many relatively simple, replaceable server components.


  • Web server
  • Print server
  • File server


  • Typically specialised for running particular services
  • Higher specifications than personal computers
  • Capable of serving multiple client computers on a network


  • More expensive than PCs
  • Require specific knowledge about services that run

Purpose of an operating system

What is an operating system?

An operating system is the most important software that runs on a computer. It manages the computer's memory and processes, as well as all of its software and hardware. It also allows you to communicate with the computer without knowing how to speak the computer's language. Without an operating system, a computer is useless.

The operating system's job

Your computer's operating system (OS) manages all of the software and hardware on the computer. Most of the time, there are several different computer programs running at the same time, and they all need to access your computer's central processing unit (CPU), memory, and storage. The operating system coordinates all of this to make sure each program gets what it needs.

Computer Basics: Understanding Operating Systems

Types of operating systems

Microsoft Windows

Microsoft Windows, or simply Windows, is a family of graphical operating systems developed, marketed, and sold by Microsoft. It consists of several families of operating systems, each of which cater to a certain sector of the computing industry with the OS typically associated with IBM PC compatible architecture.

Release versions

  • Windows 10
  • Windows 8
  • Windows 7
  • Windows Vista
  • Windows XP
  • Early Versions

Other versions

  • Windows Server
  • Windows NT
  • Windows Embedded

Mac OS

The family of Macintosh operating systems developed by Apple Inc. includes the graphical user interface-based operating systems it has designed for use with its Macintosh series of personal computers since 1984, as well as the related system software it once created for compatible third-party systems.

Desktop release versions

Other release versions

  • Mac OS X Server 1.0
  • macOS Server


iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple Inc. exclusively for its hardware. It is the operating system that presently powers many of the company's mobile devices, including the iPhone, iPad, and iPod Touch. It is the second most popular mobile operating system globally after Android.

Release versions


Android is a mobile operating system developed by Google, based on the Linux kernel and designed primarily for touchscreen mobile devices such as smartphones and tablets. Android's user interface is mainly based on direct manipulation, using touch gestures that loosely correspond to real-world actions, such as swiping, tapping and pinching, to manipulate on-screen objects, along with a virtual keyboard for text input.

Mobile release versions

Other release versions

  • Android TV
  • Android Auto
  • Android Wear


Linux is a Unix-like computer operating system assembled under the model of free and open-source software development and distribution. The defining component of Linux is the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds.

Linux was originally developed for personal computers based on the Intel x86 architecture, but has since been ported to more platforms than any other operating system. Because of the dominance of Android on smartphones, Linux has the largest installed base of all general-purpose operating systems. Linux is also the leading operating system on servers and other big iron systems such as mainframe computers, and is used on 99.6% of the TOP500 supercomputers.

Release versions

Functions of an operating system (OS)

User interface

The interaction between the user and the machine. The user interface includes hardware and software components.

Managing system resources


Managing security and access rights


Running applications


Identification of software compatibility issues

Running older software on current hardware


Newer software running on older hardware



Describe criteria when selecting hardware and software for a specified purpose, including the minimum hardware requirements to run software