Zettabyte

A zettabyte (symbol ZB, derived from the SI prefix zetta-) is a unit of information or computer storage equal to one sextillion (one long scale trilliard) bytes.^[1][2][3][4]

• 1,000,000,000,000,000,000,000 bytes = 1000⁷, or 10²¹.

An alternative (rarely used) definition is^[5]

• 1,180,591,620,717,411,303,424 bytes = 1024⁷, or 2⁷⁰.

The term "zebibyte" (or ZiB), using a binary prefix, has been proposed as an unambiguous reference to the latter value.

How big is a zettabyte?

A zettabyte is equal to 1 billion terabytes.

According to IDC, as of 2006 the total amount of digital data in existence was 0.161 zettabytes; the same paper estimates that by 2010, the rate of digital data generated worldwide will be 0.988 zettabytes per year.^[6]

A white paper released on March 11, 2008 from IDC revised the research firm's earlier estimates to show that by 2011, the amount of electronic data created and stored will grow to 10 times the 180 exabytes that existed in 2006, reflecting a compound annual growth rate of almost 60%.^[7]

By 2011, there will be 1,800 exabytes of electronic data in existence, or 1.8 zettabytes (an exabyte is equal to 1 billion gigabytes).^{[citation needed]}

IDC also acknowledged that it underestimated earlier digital data figures for 2007, saying the actual amount of data — 281 exabytes — is 10% greater than it had previously forecast in the first "Digital Universe" study. IDC said the bigger numbers were the result of faster growth in digital cameras and televisions, as well as a better understanding of data replication.^[8]

Mark Liberman calculated the storage requirements for all human speech ever spoken at 42 zettabytes, if digitized as 16 kHz 16-bit audio. This was done in response to a popular expression that states "all words ever spoken by human beings" could be stored in approximately 5 exabytes of data (see exabyte for details). Liberman did "freely confess that maybe the authors [of the exabyte estimate] were thinking about text."^[9]

References to the word

The ZFS file system originally stood for Zettabyte File System, although it is limited to a maximum addressable filesystem size of 16 EiB as presently implemented (with 64-bit pointers), less than 1.6% of a full ZiB, which would require 70-bit pointers.^[10]

HP states that HP-UX 11i v3 "enables…100 million zettabytes of storage",^[11] although the product release notes state that the maximum supported size for an individual filesystem is 40 TB (0.000 000 004 zettabytes);^[12] 25 quadrillion separate filesystems would be required to reach the stated number.^{[citations needed]}

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^[13]. Internet traffic alone is nearly half a zettabyte of traffic by 2013.

See also

• Zettabit
• Exabyte
• Yottabyte
• Orders of magnitude (data)

References