Exabyte

The exabyte (derived from the SI prefix exa-) is a unit of information or computer storage equal to one quintillion bytes (short scale). The unit symbol for the exabyte is EB. The unit prefix exaindicates the sixth power of 1000:

• 1 EB = 1000000000000000000B = 10¹⁸ bytes = 1073741824 gigabytes = 1048576 terabytes

The exbibyte, using a binary prefix, is the analogous power 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]

Contents   [hide]  1 Usage examples 2 Practical comparisons 2.1 All words ever spoken 3 See also 4 References 5 External links

[edit]Usage examples

• The world's technological capacity to store information grew from 2.6 (optimally compressed) exabytes in 1986 to 15.8 in 1993, over 54.5 in 2000, and to 295 (optimally compressed) exabytes in 2007. This is equivalent to less than one 730-MB CD-ROM per person in 1986 (539 MB per person), roughly 4 CD-ROMper person of 1993, 12 CD-ROM per person in the year 2000, and almost 61 CD-ROM per person in 2007. Piling up the imagined 404 billion CD-ROM from 2007 would create a stack from the earth to the moon and a quarter of this distance beyond (with 1.2 mm thickness per CD).^[2]

• The world’s technological capacity to receive information through one-way broadcast networks was 432 exabytes of (optimally compressed) information in 1986, 715 (optimally compressed) exabytes in 1993, 1,200 (optimally compressed) exabytes in 2000, and 1,900 in 2007.^[2]

• The world's effective capacity to exchange information through two-way telecommunication networks was 0.281 exabytes of (optimally compressed) information in 1986, 0.471 in 1993, 2.2 in 2000, and 65 (optimally compressed) exabytes in 2007.^[2]

• In 2004, the global monthly Internet traffic passed 1 exabyte for the first time. In January 2007, Bret Swanson of the Discovery Institute coined the termexaflood for a supposedly impending flood of exabytes that would cause the Internet's congestive collapse.^[3][4] Nevertheless, the global Internet traffic has continued its exponential growth, undisturbed, and as of March 2010 it is estimated at 21 exabytes per month.^[5]

• 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 azettabyte 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.^[6]

• As of May 2009, the size of the world's total digital content has been roughly estimated to be 500 Exabytes.^[7]

• 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.^[8][9][10]

• According to CSIRO, in the next decade, astronomers expect to be processing 10 petabytes of data every hour from the Square Kilometre Array (SKA) telescope.^[11] The array is thus expected to generate approximately one exabyte every four days of operation. According to IBM, the new SKA telescope initiative will generate over an exabyte of data every day. IBM is designing hardware to process this information.^[12]

• According to the Digital Britain Report,^[13] 494 exabytes of data was transferred across the globe on June 15, 2009.

Several filesystems use disk formats that support theoretical volume sizes of several exabytes, including Btrfs, XFS, ZFS, exFAT, NTFS, and ReFS.

• The ext4 file system format supports volumes up to 1 exabyte in size, although the userspace tools cannot yet administer such filesystems.

• Oracle Corporation claimed^[14] the first Exabyte tape library with the SL8500 and the T10000C tape drive in January 2011.

[edit]Practical comparisons

[edit]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,^[15][16][17] often citing a project at the UC Berkeley School of Information in support.^[18] 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.^[19] This statement has been criticized.^[20][21] 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."^[22]

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.^[23] 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."^[18]International Data Corporation estimates that approximately 160 exabytes of digital information were created, captured, and replicated worldwide in 2006.^[24] A research from University of Southern California estimates that the amount of data stored in the world by 2007 as 295 exabytes and the amount of information shared on two-way communications technology, such as cell phones in 2007 as 65 exabytes.^[25][26]