Bits - the smallest unit of storageYou can think of a bit like a match box. The more you need to store the more bits, or boxes, you need. |
Computers can only understand 2 states. The circuit below shows us how this works in practice.
The smallest unit of storage in a computer is a BIT. This can hold 2 values - either a 0 to represent off or a 1 to represent on. If you have 2 bits, you can represent 4 values; 3 bits can represent 8 values, 4 bits, 16 etc. This is shown in the table below. |
Why do computers use binary
Representing data in a binary system
All data in a computer system has to be converted into binary for the computer to understand it. This is because the computer only uses 2 states. All computing is done inside the Arithmetic Logic Unit (ALU) of the Central Processing Unit and is all done using the tiny switches called transistors.
To understand this, you first have to understand how our base 10 number system, also known as denary, can be represented in binary.
To understand this, you first have to understand how our base 10 number system, also known as denary, can be represented in binary.
The animation above shows how the numbers 1 to 15 are represented in binary. We already know that to represent 15 combinations, we need 4 bits and you can see the 4 bits shown here.
4 bits is known as a nibble. A nibble is half a byte as there are 8 bits in a byte. To convert from a binary number to a denary number we use these place values.
In the animation above you can see that if there is a 1 in position 8 and a 1 in position 1, this gives the denary value 9 because we add 8+1. To convert from a denary number to a binary number we use a similar method. Watch the video below! |
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Everything has to be converted into binary so it can be processed and stored by a computer.
Everything includes:
We can understand this by first understanding how text, images and sound can be represented in denary numbers. Then as long as we know how we convert from denary into binary we can understand how something as complex as a photo can be represented using only 1s and 0s. |
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