Zettabyte

A zettabyte (derived from the SI prefix zetta- ) is a unit of measurement in computers of one thousand million million million (American sextillion) bytes. Its abbreviation is ZB.

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 bytes - or 10²¹.
2. 1,180,591,620,717,411,303,424 bytes - 1024⁷, or 2⁷⁰. This is 1024 times an exabyte. This is the definition most often used in computer science and computer programming.

See integral data type.

To clarify the distinction between decimal and binary prefixes, the International Electrotechnical Commission (IEC), a standards body, in 1998 defined new prefixes by combining the International System of Units (SI) prefixes with the word "binary" (see Binary prefix). They did not provide a name for this number, although, it would probably be zebibyte (ZiB). This naming convention has not, as of 2004, been widely adopted. There are 1000 zettabytes in a yottabyte using the first definition, or 1024 zebibytes in a yobibyte using the second definition.

The prefix "zetta" comes from the Latin septum(via Italian sette), meaning "seven", and is used here to represent one thousand to the seventh power.

See also

• Yottabyte
• Binary prefix

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

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