Terabyte: Wikis

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Updated live from Wikipedia, last check: June 04, 2012 11:53 UTC (50 seconds ago)

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This article is about a measurement term for data storage capacity. For the fictional species, see Terabyte (insect).

Prefixes for bit and byte multiples

Decimal
Value	SI
1000	k	kilo
1000²	M	mega
1000³	G	giga
1000⁴	T	tera
1000⁵	P	peta
1000⁶	E	exa
1000⁷	Z	zetta
1000⁸	Y	yotta

Binary
Value	IEC		JEDEC
1024	Ki	kibi	K	kilo
1024²	Mi	mebi	M	mega
1024³	Gi	gibi	G	giga
1024⁴	Ti	tebi
1024⁵	Pi	pebi
1024⁶	Ei	exbi
1024⁷	Zi	zebi
1024⁸	Yi	yobi

A terabyte (or Tbyte) is a SI-multiple (see prefix tera) of the unit byte for digital information storage and is equal to 10¹² (1 trillion short scale) bytes or 1000 gigabytes. The unit symbol for the terabyte is TB.

The designation terabyte is rarely used to refer to the tebibyte, its binary prefix analogue, because only recent (since 2007) disk drives have this capacity. Disk drive sizes are always designated in SI units by manufacturers. However, a possible confusion arises from this definition with the long-standing tradition in some fields of information technology and the computer industry of using binary prefix interpretations for memory sizes. Standards organizations such as International Electrotechnical Commission (IEC), Institute of Electrical and Electronics Engineers (IEEE) and International Organization for Standardization (ISO) recommend to use the alternative term tebibyte to signify the traditional measure of 1024⁴ bytes, or 1024 gibibytes, leading to the following definitions:

In standard SI usage, 1 terabyte (TB) equals 1000000000000bytes = 1000⁴ or 10¹² bytes.
Using the traditional binary interpretation, a terabyte would be 1099511627776bytes = 1024⁴ = 2⁴⁰ bytes = 1 tebibyte (TiB).

The capacities of computer storage devices are typically specified using their the standard SI meaning of unit prefixes, but many operating systems and applications report in binary-based units. Mac OS X 10.6 (Snow Leopard) reports decimal units.

Examples of terabyte usage

Examples of the use of "terabyte" to describe data sizes in different fields are:

Library data - The U.S. Library of Congress Web Capture team has claimed that "As of May 2009, the Library has collected almost 100 terabytes of data".^[1]
Online data bases - Ancestry.com claims approximately 600 TB of genealogical data with the inclusion of US Census data from 1790 to 1930.^[2]
Computer hardware - Hitachi introduced the world's first one terabyte hard disk drive in 2007.^[3]
Internet traffic - In 1993, total Internet traffic amounted to approx. 100 TB for the year.^[4] As of June 2008, Cisco Systems estimated Internet traffic at 160 TB/s (which assuming to be statistically constant comes to 5 zettabytes for the year).^[5]
Social networks - As of May 2009, Yahoo! Groups had "40 terabytes of data to index" ^[6]
Video - Released in 2009, the 3D animated film Monsters vs. Aliens used 100 TB of storage during development.^[7]
Usenet messages - In October of 2000, the Deja News Usenet archive had stored over 500 million Usenet messages which used 1.5 TB of storage^[8]

References

^ "How large is the Library's archive?". 2007-05-26. http://www.loc.gov/webcapture/faq.html.
^ "Ancestry.com Adds U.S. Census Records". 2006-06-22. http://www.cbsnews.com/stories/2006/06/22/tech/main1740956.shtml.
^ "Hitachi Introduces 1-Terabyte Hard Drive". PC World. 2007-01-07. http://www.pcworld.com/article/128400/hitachi_introduces_1terabyte_hard_drive.html. Retrieved 2008-09-15.
^ http://www.disco-tech.org/2007/10/an_exabyte_here_an_exabyte_the.php
^ White, Bobby (2008-06-16). "Cisco Projects Growth To Swell for Online Video". The Wall Street Journal. http://online.wsj.com/article/SB121358372172676391.html.
^ "Yahoo! Groups Blog". 2009-05-09. http://www.ygroupsblog.com/blog/2009/03/17/groups-search-update/.
^ IRENE THAM (2009-04-08). "Taking a monster hit; Massive computer power was needed to create the 3-D movie Monsters Vs Aliens.". The Straits Times. "The 3-D movie used up close to 100 terabytes of disk space and more than 40 million hours of rendering."
^ "Usenet Sale: Sounds to Silence?". 2000-10-25. http://www.wired.com/science/discoveries/news/2000/10/39622. Retrieved 2009-10-13. "It's loaded with 500 million postings ... [and has] ballooned to over 1.5 terabytes"

Units of information

Base units	Bit · Byte

Related units	Nibble · Word · Octet

Traditional units	Kilobyte · Megabyte · Gigabyte · Terabyte · Petabyte · Exabyte · Zettabyte · Yottabyte

IEC standard units	Kibibyte · Mebibyte · Gibibyte · Tebibyte · Pebibyte · Exbibyte · Zebibyte · Yobibyte

Bit-based units	Kilobit · Megabit · Gigabit · Terabit · Petabit · Exabit · Zettabit · Yottabit

Categories: Units of information

Hidden categories: Articles containing potentially dated statements from June 2008 | All articles containing potentially dated statements

Simple English

A terabyte (TB) is a unit of measurement in computers and similar electronic devices. Terabytes hold 1000 gigabytes (GB) or a trillion (1,000,000,000,000) bytes, and 1000 terabytes make one petabyte. Some people say that the exact number of bytes is 1,099,511,627,776.^{[needs proof]} The correct term used for this exact figure is tebibyte.

Large organisations use terabytes of storage to hold massive amounts of data. People at home probably do not use terabytes, they would use gigabytes, megabytes and occasionally kilobytes. However, in the future terabytes of storage will probably be more common in home usage. In fact, according to this page on the Apple website, 2008 Apple iMac computers can be ordered with 1 TB hard drives. An external hard drive can be several terabytes. Usually, one terabyte of space costs between 100 and 150$.^[1]