Digital data

As a human you are constantly processing data. This type of data is in analogue form. Analogue data comes in a continuous stream, like sound or light waves. Everything you see or hear is an uninterrupted flow of data to your senses.

Computers are not able to process analogue data. They need data to be in a different, digital form. Any data we want a computer to process must first be converted to digital. Digital data is made up of binary digits.

The circuits in a computer processor are made up of billions of transistors. A transistor is a tiny switch activated by the electronic signals it receives. The digits 1 and 0 used in binary reflect the 'on' and 'off' states of a transistor.

Bits and binary

The number system we use every day is called decimal, denary or base 10, as there are ten possible numbers: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

The number system that computers use is called the binary or base 2 number system as there are just two possible numbers. Only the digits 0 and 1 are used to store data. A binary digit, or bit, is the smallest unit of data in computing.

A bit is represented by a 0 or a 1. Binary numbers are made up of binary digits (bits), e.g. the 4-bit binary number 1101 is 13 in decimal while 1101.101 is 13.625 in decimal.

The decimal number 13.625 represented in binaryThe decimal number 13.625 represented in binary

Data types

Data can be stored in many different formats called 'data types'. Common data types are described below:

Data typeDescriptionExample data
IntegerWhole numbers only0, 1, 2, 3
Real/FloatNumbers that can have a decimal part0.1, 1.2, 3.4
BooleanTwo values only - 'true' and 'false'True/False, 1/0, Y/N
CharacterA single letter, number or symbolA, B, C, @, *
StringUsed for text – can include any characterDigital Technology
Date/TimeUsed for dates and times20:55, 29/11/2016