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An exabyte (derived from the SI prefix exa-) is a unit of information or computer storage equal to one quintillion bytes (short scale). It is commonly abbreviated EB. When used with byte multiples, the unit indicates a power of 1000:

• 1 EB = 1,000,000,000,000,000,000 B = 10¹⁸ bytes or 1 billion gigabytes

The term exbibyte, using a binary prefix, is used for powers of 1024 bytes.

In principle, the 64-bit microprocessors found in many computers can address 16 exbibytes, or just over 18 exabytes, of memory.^[1]

Exabyte in use

As of December 2008, the global monthly Internet traffic is estimated to be 5 to 8 exabytes.^[2] As of May 2009, the size of the World's total Digital content has been roughly estimated to be 500 billion gigabytes, or 500 exabytes.^[3]

According to an IDC paper sponsored by EMC Corporation, 161 exabytes of data were created in 2006, "3 million times the amount of information contained in all the books ever written," with the number expected to hit 988 exabytes in 2010.^[4][5][6]

According to CSIRO, in the next decade, astronomers expect to be processing 10 petabytes of data every hour from the Square Kilometre Array telescope.^[7] The array is thus expected to generate approximately one exabyte every four days of operation.

According to the June 2009 update of the Cisco Visual Networking Index IP traffic forecast, by 2013, annual global IP traffic will reach two-thirds of a zettabyte or 667 exabytes. Internet video will generate over 18 exabytes per month in 2013. Global mobile data traffic will grow at a CAGR of 131 percent between 2008 and 2013, reaching over two exabytes per month by 2013.^{[8 ]}

According to the Digital Britain Report ^[9] 494 Exabytes of data was transferred across the globe on the 15th June 2009.

The ext4 file system supports volumes up to 1 exabyte in size, along with the NTFS system.

Practical comparisons

"All words ever spoken"

A popular expression claims that "all words ever spoken by human beings" could be stored in approximately 5 exabytes of data,^[10][11][12] often citing a project at the UC Berkeley School of Information in support.^[13] The 2003 University of California Berkeley report credits the estimate to the website of Caltech researcher Roy Williams, where the statement can be found as early as May 1999.^[14] This statement has been criticized.^[15][16] Mark Liberman calculated the storage requirements for all human speech at 42 zettabytes (42,000 exabytes, and 8,400 times the original estimate), if digitized as 16 kHz 16-bit audio, although he did "freely confess that maybe the authors [of the exabyte estimate] were thinking about text."^[17]

Earlier Berkeley studies estimated that by the end of 1999, the sum of human-produced information (including all audio, video recordings and text/books) was about 12 exabytes of data.^[18] The 2003 Berkeley report stated that in 2002 alone, "telephone calls worldwide on both landlines and mobile phones contained 17.3 exabytes of new information if stored in digital form" and that "it would take 9.25 exabytes of storage to hold all U.S. [telephone] calls each year."^[13] International Data Corporation estimates that approximately 160 exabytes of digital information were created, captured, and replicated worldwide in 2006.^[19]

Exaflood

The word exabyte is the basis for the term exaflood, a neologism created by Bret Swanson of the Discovery Institute in a January 2007 Wall Street Journal editorial.^[20] Exaflood refers to the rapidly increasing torrent of data transmitted over the Internet. The amount of information people upload, download and share on the Internet—known as internet traffic—is growing (due in large part to video, audio and photo applications) at an exponential rate, while the capacity of the Internet, its bandwidth, is limited and susceptible to a "flood" of data equal to multiple exabytes. "One exabyte is the equivalent of about 50,000 years of DVD quality video."^[21]

See also

• Binary prefix
• Orders of magnitude (data)

References

External links

• exabyte (whatis.com definition)