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Title: Terabytes  
Author: World Heritage Encyclopedia
Language: English
Subject: Internet traffic
Publisher: World Heritage Encyclopedia


Multiples of bytes
Value Metric
1000 kB kilobyte
10002 MB megabyte
10003 GB gigabyte
10004 TB terabyte
10005 PB petabyte
10006 EB exabyte
10007 ZB zettabyte
10008 YB yottabyte
1024 KB kilobyte KiB kibibyte
10242 MB megabyte MiB mebibyte
10243 GB gigabyte GiB gibibyte
10244 - - TiB tebibyte
10245 - - PiB pebibyte
10246 - - EiB exbibyte
10247 - - ZiB zebibyte
10248 - - YiB yobibyte
Orders of magnitude of data

The terabyte is a multiple of the unit byte for digital information. The prefix tera represents the fourth power of 1000, and means 1012 in the International System of Units (SI), and therefore one terabyte is one trillion (short scale) bytes. The unit symbol for the terabyte is TB.

1 TB = 1000000000000bytes = 1012bytes = 1000gigabytes.

A related unit, the tebibyte (TiB), using a binary prefix, is the corresponding 4th power of 1024. One terabyte expressed using binary prefixes is about 0.910 tebibytes, or 931 gibibytes.


The first hard disk drives were created in the 1950s-1960s and were the size of a refrigerator hard disks of terabyte size did not appear until the late 2000s. In 2012, a 1 terabyte disk drive is 2.5 inches wide and fits inside a laptop computer.


In 1991, consumer grade, 1 gigabyte (1/1000 TB) disk drives were available for $2699 and up,[12] and two years later prices for this capacity had dropped to $1499.[13] By 1995, 1 GB drives could be purchased for $849.[14]

  • 2007 1 terabyte hard disk $370 ($421 adjusted for inflation)
  • 2010 2 terabyte hard disk $200 ($216 adjusted for inflation)
  • 2012 4 terabyte hard disk $450 (Hitachi, largest available in consumer market), 1 terabyte hard disk $100
  • 2013 4 terabyte hard disk $179, 3 terabyte hard disk $129, 2 terabyte HD $100, 1 terabyte HD $80

Note: $ currency are in USD and not adjusted for inflation

Illustrative usage examples

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 claims that "As of April 2011, the Library has collected about 235 terabytes of data" and that it adds about 5 terabytes per month.[15]
  • Online claims approximately 600 TB of genealogical data with the inclusion of US Census data from 1790 to 1930.[16]
  • Computer hardwareHitachi introduced the world's first one terabyte hard disk drive in 2007.[17]
  • Historical Internet traffic – In 1993, total Internet traffic amounted to approximately 100 TB for the year.[18] 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).[19] In other words, the amount of Internet used per second in 2008 exceeded all of the Internet used in 1993.
  • Social networks – As of May 2009, Yahoo! Groups had "40 terabytes of data to index".[20]
  • Video – Released in 2009, the 3D animated film Monsters vs. Aliens used 100 TB of storage during development.[21]
  • Usenet messages – In October 2000, the Deja News Usenet archive had stored over 500 million Usenet messages which used 1.5 TB of storage.[22]
  • EncyclopediaWorld Heritage Encyclopedia's January 2010 raw data uses a 5.87 terabyte dump.[23]
  • Climate science – In 2010, the German Climate Computing Centre (DKRZ) was generating 10,000 TB of data per year, from a supercomputer with a 20 TB memory and 7,000 TB disk space.[24]
  • Audio – One terabyte of audio recorded at CD quality will contain around 2,000 hours of audio. Additionally, one terabyte of compressed audio recorded at 128 kB/s will contain about 17,000 hours of audio.
  • The Hubble Space Telescope has amassed more than 45 terabytes of data in its first 20 years worth of observations.[25]
  • The IBM computer Watson, against which Jeopardy! contestants competed in February 2011, has 16 terabytes of RAM.[26]

See also


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