What is a computer?


Commodore AMIGA

In simple terms, a computer is an electronic device that stores and processes data according to instructions given to it by a user or predefined programme. In today's world, computers are everywhere. From the moment we wake up (an alarm in our mobile phone) to the moment we go to bed (the clock on the smart TV telling us what time it is) we are surrounded by them and our lives governed by our interactions with them.

In the last 100 years many technological advances have been made that have revolutionised our world and make many aspects of our daily lives unrecognisable to how we lived and what we did only a century ago.

Imagine what your day would look like without a computer, what would be different? What would you not be able to do? In your lifetime there has already been many advances that have completely changed our lives, over the rest of your life there will be many more.

Explore the slide show below showing some of the technological advances in the last century and how they have evolved with time.

How many of these items do you recognise and how many have you used? How many seem very old fashioned already? Take note of the dates for each image.


Most people think of a computers such as a laptop or desktop used by a single individual, but it's worth remembering that computers come in all different shapes and sizes depending on their function. For example, taking money out from a bank cashpoint, scanning your Oyster card on the bus or tube, using a calculator or paying for items at the supermarket with a credit card, pressing the cross button at traffic lights, all use a type of computer.

  • Desktop computer: These are typically used at work, home and school. They can vary in size from pocket sized to small versions to large box sized. Once you add a monitor, mouse and keyboard you have what is typically referred to as a desktop computer. They are usually easy to upgrade and expand, allowing you to add new parts or change existing ones, for example, a better video card for gaming, or a new larger hard drive for extra storage.

  • Laptop Computer: These can be battery allowing them to be used in a wider variety of locations portable in comparison to desktop computers. Since laptops are smaller than desktop computers it is more difficult to access the internal architecture of the computer and so they are more difficult, often impossible, to upgrade or expand. They are usually more expensive that an equivalent specification machine when compared to a desktop computer.


ICL Mainframe

ICL Mainframe

  • Server: This is a computer that 'serves up' information to different computers on a network. This is useful in businesses where you want to share files between machines. They can be stored on a file server and accessed on many different machines by different employees. Servers also enable the internet to work. 'Web servers' are where web pages are stored. When you click a link on an internet page, the web server that page is stored on delivers the page to you to view on your computer as requested.

Other types of computer – specialised computers


Tablet Computers

  • Tablet Computers: These use a 'touch screen' to type and navigate so you don't need a keyboard or mouse. They are therefore even more portable than a laptop. The most recognisable brand at present is the iPad.

  • Mobile Phones: Nowadays we have 'smartphones'. These can perform a lot of things a computer can do such as browsing the internet or playing games. They hold a lot of processing power in a very small package. When compared to the early personal computers which could be very large, the relatively small 'smartphones' outperform them considerably.

  • Games Consoles: These are specialised kinds of computers that are used for playing video games. Although not as fully-functional as a desktop computer, many of the newer consoles are branching out allowing you to do non-gaming activities such as browsing the internet or watching movies online.

  • TVs: Much like 'smartphones', many TVs now include 'apps' that let you go online and access web resources such as iplayer, Netflix or Facebook.
  • What is computer?

    Running time: 02:09

Teacher Notes




  • A world of computers