Data Representation
Everything a computer stores — whether it’s text, numbers, images, or sound — must be converted into binary, a language made up of just 1s and 0s. This is called data representation.
Computers use different methods to represent different types of data. At National 5 level, you need to know five main types of data representation:
Binary
Binary is the number system computers use. It only uses two digits: 1 and 0.
Each binary digit (or bit) represents a power of 2. Binary is used to represent whole numbers.
Mantissa and Exponent
When storing very large or very small numbers, computers use floating-point representation, which has two parts:
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The mantissa: this holds the significant digits of the number.
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The exponent: this tells you how many places to move the decimal point.
ASCII
Text is stored using character sets. The most common one is ASCII, which stands for American Standard Code for Information Interchange.
Each letter, number, or symbol is matched with a unique binary code.
Bitmap Graphics
Bitmapped graphics store images as a grid of tiny squares called pixels.
Each pixel has a binary value that stores its colour. The more bits per pixel, the more colours can be displayed.
Vector Graphics
Vector graphics store images using shapes and instructions, like “draw a line here” or “fill this circle with red.”
They take up less memory than bitmaps and can be resized without losing quality.
Understanding how data is represented allows us to see how computers make sense of everything we input — from numbers and letters to detailed graphics. Each data type is stored in a unique way, but it all comes back to one thing: binary. Once you understand these five methods, you’re well on your way to understanding how computers actually work behind the scenes.