2. Storage Capacity

Data can be stored either in the 'internal memory' or on a 'storage device'.

The amount of data and instructions that can be stored is measured in 'bytes'.

One byte contains 8 bits (short for Binary Digit). This is the smallest unit of data that can be stored. Each 'bit' is represented as a binary number, either 1 or 0.

A single keyboard character such as the letter A or T takes one byte of storage.

bits and bytes

We normally refer to the capacity of a storage device in terms of Kilobytes (KB), Megabytes (MB), Gigabytes (GB) - or even Terabytes!

Storage sizes
Quantity	Information
Bit	Smallest unit of data, either a 0 or 1
Byte	8 bits
Kilobyte (Kb)	Assumed to be 1,000 bytes. In reality, it is really 1,024 bytes.
Megabyte (Mb)	1,000 kilobytes (1,024 Kb)
Gigabyte (Gb)	1,000 megabytes (1,024 Mb)