Bits and Bytes

This page relates to things like capacities of hard disk drives, DVD ROMS, etc, in fact anything that can store data and infromation. We've all heard of bits and bytes, so let's see what they are.

The smallest piece of computer data is the bit.We are going to touch on binary, binary is a number system where there are only two numbers, 1 and 0. A 1 means on and a 0 means off, a bit can be either on (1) or off (0) and this pattern of 1's (on) and 0's (off) makes up the individual patterns for the characters. Eight bits make up one byte (which is equal to one character on the keyboard) so if we take the letter A as an example:

The letter A in binary is 00100001, that equates to:

What does the above mean?

Also, we have what is known as an ASCII table (American Standard Code for Information Interchange) where each character relates to a decimal equivalent of the binary number representing the character.

As an example, take the letter A, in ASCII it would be represented as 65, in binary it would be 00100001( as shown in the picture above). How does this come about?, let's see:

Each binary position represents a decimal value going from the right to the left each successive number is 2x the previous number, so, we start at 1 then 2x =2, 2x2=4, 2x4=8, 2x8=16, 2x16=32, 2x32=64, 2x64=128

Now, when we have the binary representation in place under the relevant columns we add the numbers that relate to a binary 1. So, in the above axample of the letter A, there is a 1 under 64 and a 1 under 1 so 64 +1 = 65.

The binary for the letter A is 01000001 and the decimal (ASCII) is 65

Where does a byte come into it all?

A byte is eight bits so the eight bits of the binary number 01000001 would be 1 byte, we can view 1 byte as 1 character.

There are 1,024 bytes in a Kilobyte (Kb) so 1k would be 1,024 bytes (and just for reference that would be 8,192 bits) so to keep things as simple as possible, we'll round these figures up and give approximate values and totals so 1k would be 1000 bytes (forget the bits)

1,000 bytes = 1 Kilobyte (Kb)

1,000,000 Kilobytes (Kb) = 1 Megabyte (Mb)

1,000,000,000 Megabytes(Mb) = 1 Gigabyte(Gb)

If you wish to go up to terrabytes (Tb) or further then please feel free to do so.