An exabyte (derived from the
SI prefix" exa-") is a unit of informationor computer storageequal to one quintillion bytes. It is commonly abbreviated EB. When used with byte multiples, the SI prefix may indicate a power of either 1000 or 1024, so the exact number may be either:
* 1,000,000,000,000,000,000 bytes — 10006, or 1018; or
* 1,152,921,504,606,846,976 bytes — 10246, or 260.
The term "
exbibyte", using a binary prefix, has been proposed as an unambiguous reference to the latter value.
64-bitmicroprocessors found in many computers can allocate up to 16 exabytes of RAM to a program. [cite web | url=http://publib.boulder.ibm.com/infocenter/zoslnctr/v1r7/topic/com.ibm.zconcepts.doc/zconcepts_102.html | title=A brief history of virtual storage and 64-bit addressability | accessdate=2007-02-17]
CSIRO, in the next decade, astronomers expect to be processing 10 million gigabytes of data every hour from the Square Kilometre Arraytelescope. [cite web | url=http://www.csiro.au/news/ps3ng.html | title=From molecules to the Milky Way: dealing with the data deluge | accessdate=2007-11-10] The array is thus expected to generate approximately one exabyte every four days of operation.
"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, [cite web | url=http://www.nytimes.com/2003/11/12/opinion/12WED4.html | publisher=
New York Times| title=Trying to Measure the Amount of Information That Humans Create | author=Verlyn Klinkenborg | date=November 12, 2003 | accessdate=2006-07-19 (login)] [cite web | url=http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci944596,00.html | title=How many bytes for... | publisher=techtarget.com | accessdate=2006-07-19] [cite web | url=http://news.uns.purdue.edu/html3month/2005/051206.McKay.petabyte.html | title='Robbie the Robot' making data easier to mine | date=December 6, 2005 | publisher=purdue.edu | accessdate=2007-02-17] often citing a project at the UC Berkeley School of Informationin support.cite web | url=http://www.sims.berkeley.edu:8000/research/projects/how-much-info-2003/execsum.htm | title=How Much Information? 2003 | publisher=berkeley.edu | accessdate=2006-07-19] The 2003 University of California Berkeley report credits the estimate to the website of Caltechresearcher Roy Williams, where the statement can be found as early as May 1999. [cite web | archiveurl=http://web.archive.org/web/19990508062723/http://www.ccsf.caltech.edu/~roy/dataquan/ | title=Data Powers of Ten | author=Roy Williams | archivedate=1999-05-08 | accessdate=2006-07-19 | url=http://www.ccsf.caltech.edu/~roy/dataquan/] This statement has been criticized. [cite web | author=Mark Liberman | authorlink = Mark Liberman | url=http://itre.cis.upenn.edu/~myl/languagelog/archives/000110.html | title=More on the 5 exabyte mistake | date=November 12, 2003 | publisher=upenn.edu | accessdate=2006-07-19] [cite web | url=http://brian.carnell.com/archives/years/2003/12/000022.html | title=How Much Storage Is Required to Store Every Word Ever Spoken by Human Beings? | date=December 31, 2003 | author=Brian Carnell | publisher=brian.carnell.com | accessdate=2006-07-19] Mark Libermancalculated the storage requirements for all human speech at 42 zettabytes, 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." [cite web | url=http://itre.cis.upenn.edu/~myl/languagelog/archives/000087.html | title=Zettascale Linguistics | author=Mark Liberman | authorlink=Mark Liberman | date=November 3, 2003 | publisher=upenn.edu | accessdate=2007-02-17]
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. [cite web | url=http://www.cio.com/archive/092203/enriquez.html | title=The Data That Defines Us | year=2003 | month= Fall/Winter | author=Juan Enriquez | publisher=CIO Magazine | accessdate=2006-07-19] 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." International Data Corporation estimates that approximately 160 exabytes of digital information were created, captured, and replicated worldwide in 2006. [cite web | url=http://www.businessweek.com/ap/financialnews/D8NMAG802.htm | publisher=
BusinessWeek| title=So much data, relatively little space | author=Brian Bergstein | date=March 5, 2007 | accessdate=2007-03-05]
The word "exabyte" is the basis for the term "exaflood", a
neologismcreated by Bret Swanson of the Discovery Institutein a January 2007 " Wall Street Journal" editorial.cite web | url=http://www.discovery.org/scripts/viewDB/index.php?command=view&id=3869 | title=The Coming Exaflood | author=Bret Swanson | date=January 20, 2007 | publisher= Wall Street Journal| accessdate=2007-02-17] "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 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." [cite web | author=Grant Gross | date=November 24, 2007 | url=http://www.pcworld.com/article/id,139885-pg,1/article.html | title=Internet Could Max Out in 2 Years, Study Says | publisher=PC World | accessdate=2007-11-28]
* In the movie "
Ocean's Thirteen", The Bank Hotel and Casino's advanced AIsecurity system, "The Greco", is said to process game winners' reactions "in a field of exabytes". Danny Ocean ( George Clooney) goes on to ask what an exabyte is, whereupon Rusty ( Brad Pitt) explains, "a million terabytes."
orders of magnitude (data)
* [http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci212085,00.html exabyte (whatis.com definition)]
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