Early electronic computers, developed around the 1940’s, were the size of a large room and consumed huge amounts of electricity. They were vastly different to the modern computers we use today, especially when compared to small and portable laptop computers.

Computers are programmed to carry out instructions. These instructions are usually very simple and require adding numbers together, moving data from one place to another etc.

A computer program can include as little as a few instructions to upwards of millions of instructions depending on the complexity of the program. Modern applications such as word processors, web browsers and graphic editors take large teams of programmers a long time to complete.

A computer’s memory stores numbers in huge amounts of cells that are addressed and can be quickly accessed by the CPU to perform calculations. There are two main types of computer memory, ROM (read only memory) and RAM (random access memory). ROM contains pre-written software and data that the CPU can only read, while RAM can be accessed and written to at any time.

Computers interact with a number of different I/O (input/output) devices to exchange information. These peripheral devices include the keyboard, mouse, display, hard drive, printer and more.

Computers are used to help link the world in the form of networks. Networked computers allow users to share and exchange data that is stored in different locations. You may have heard of a local area network (LAN) or wide area network (WAN) which connects areas of various sizes. The Internet is a vast network of computers spanning the globe that allows users to access email, the World Wide Web and other applications.

Although we normally think of computers as the ones we use in our everyday lives to surf the web, write documents etc, small computers are also embedded into other things such as mobile phones, toys, microwaves and MP3 players. We use computers all the time, often without even knowing it!