Yottabyte

A yottabyte (derived from the SI prefix "yotta"-) is a unit of information or computer storage equal to one septillion (one long scale quadrillion or 10²⁴) bytes. It is commonly abbreviated YB. As of 2008, no computer has yet achieved one yottabyte of storage. In fact, the combined space of all the computer hard drives in the world does not amount to even one zettabyte. According to one study, all the world's computers stored approximately 160 exabytes in 2006, with nearly 1 zettabyte projected by 2010. [ [http://www.emc.com/about/destination/digital_universe/pdf/Expanding_Digital_Universe_IDC_WhitePaper_022507.pdf Expanding Digital Universe IDC White Paper (pdf)] ] When used with byte multiples, the SI prefix may indicate a power of either 1,000 or 1,024, so the exact number may be either:
* 1 septillion, or 1,000,000,000,000,000,000,000,000 bytes — 1000⁸, or 10²⁴, or
* 1,208,925,819,614,629,174,706,176 bytes — 1024¹⁰, or 2⁸⁰.Fact|date=May 2008

The term "yobibyte", using a binary prefix, has been proposed as an unambiguous reference to the latter value.

128-bit processors could become prevalent when 16 exbibytes of addressable memory is no longer enough (128-bit processors would allow for 274,877,906,944 yottabytes of memory).

One study has predicted that in ten years the volume of online data accessible either on the Internet or on corporate networks is expected to reach a yottabyte. ["IBM Unveils Storage Capacity on Demand for Growing e-businesses," Business Wire, October 27, 2000] The study refers to a yottabyte as 1 trillion terabytes.

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