Yottabyte

A yottabyte (derived from the SI prefix yotta-) is a unit of measurement in computers of one million million million million (American septillion, European quadrillion) bytes. Its abbreviation is YB.

Because of irregularities in definition and usage of the kilobyte, the exact number in common practice could be any one of the following:

1. 1,000,000,000,000,000,000,000,000 bytes - or 10 ²⁴.
2. 1,208,925,819,614,629,174,706,176 bytes - 1024⁸, or 2⁸⁰. This is 1024 times a zebibyte. This is the definition most often used in computer science and computer programming.

See integral data type.

To clarify the differences in usage between the "binary" and "decimal" uses of SI prefixes, the International Electrotechnical Commission (IEC), a standards body, in 1997 proposed that the "binary" quantities be known by new Binary prefixes which are related to but distinct from the International System of Units (SI) prefixes. As of 2004 this naming convention has not yet gained widespread use. The IEC names extend only up to "exbi-", corresponding to the SI prefix exa-. The IEC did not provide an equivalent for the SI prefix yotta- (Y; 10²⁴). Extending the apparent naming pattern used by the IEC suggests yobi- as a candidate name for 2⁸⁰ (Yi).

The prefix "yotta" comes from the Latin root octo-(via Italian otto), meaning "eight", and is used here to represent one thousand to the eighth power.

External links

• http://www.quinion.com/words/turnsofphrase/tp-kib1.htm
• http://www.nist.gov/public_affairs/techbeat/tb9903.htm
• http://www.wordspy.com/words/yottabyte.asp