Units of information

• A binary digit (or bit) is the fundamental unit of data storage, and will have a value of 0 or 1. A group of eight bits is called a byte. A group of four bits is a nibble.
• Historically, storage capacity was expressed using the metric prefixes of kilo (1,000), mega (1,000,000), etc. Since 1998 there has been a move towards using the special prefixes developed to more accurately represent binary values (as per the International System of Units (SI) definition). For example, a kibibyte is equal to 1,024 bytes, whereas a kilobyte is equal to 1,000 bytes.