Terabyte

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v • d • e Quantities of bytes
SI prefixes			Binary prefixes
Name (Symbol)	Standard SI	Alternate Use	Name (Symbol)	Value
kilobyte (kB)	10³ = 1000¹	2¹⁰	kibibyte (KiB)	2¹⁰
megabyte (MB)	10⁶ = 1000²	2²⁰	mebibyte (MiB)	2²⁰
gigabyte (GB)	10⁹ = 1000³	2³⁰	gibibyte (GiB)	2³⁰
terabyte (TB)	10¹² = 1000⁴	2⁴⁰	tebibyte (TiB)	2⁴⁰
petabyte (PB)	10¹⁵ = 1000⁵	2⁵⁰	pebibyte (PiB)	2⁵⁰
exabyte (EB)	10¹⁸ = 1000⁶	2⁶⁰	exbibyte (EiB)	2⁶⁰
zettabyte (ZB)	10²¹ = 1000⁷	2⁷⁰	zebibyte (ZiB)	2⁷⁰
yottabyte (YB)	10²⁴ = 1000⁸	2⁸⁰	yobibyte (YiB)	2⁸⁰

A terabyte (derived from the prefix tera-) is a measurement term for data storage capacity equal to 1000 gigabytes, i.e. one trillion (short scale) bytes. It is commonly abbreviated TB. "Terabytes" are often intended to mean tebibytes (i.e. 1024⁴ instead of 1000⁴). Because of the potential for confusion this creates, a number of technical standards and legal entities have recommended against this use in the past few years (see below).

The number of bytes in a terabyte often varies in common usage originating from a discrepancy between the tradition to use binary prefixes for computer memory and the SI standard.

According to the SI standard, based on radix (base) 10, a terabyte (TB) contains

1,000,000,000,000 bytes = 1000⁴ or 10¹² bytes.

According to traditional usage for computer memory, based on radix 2, a terabyte contains

1,099,511,627,776 bytes = 1024⁴ or 2⁴⁰ bytes.

For this reason, standards organizations such as IEC, IEEE and ISO recommend to use the term tebibyte (TiB) for this latter amount.

The capacities of computer storage devices are traditionally advertised using their SI standard values.

[edit] Terabytes in use

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The U.S. Library of Congress has claimed that "as of December 31, 2005, the Library has collected more than 40 terabytes of data." (2006-12-28).
One hour of uncompressed Ultra High Definition Video (UHDV) consumes approximately 11.5 terabytes of data.
A Holographic Versatile Disc (HVD) can hold up to 3.9 terabytes.
Personal computers and related devices such as TiVos containing a terabyte or more of storage space have recently become practical using combinations of high-capacity mass-market hard drives. On January 5, 2007, Hitachi announced the fist commercially available consumer 1 TB drive, which uses five 200 GB platters and perpendicular recording. Seagate is expected to release its own 1 TB drive soon.
Rapidshare has over 1000 terabytes of space used for hosting files.^{[citation needed]}
Ancestry.com now claims 600 terabytes of genealogical data with the inclusion of US Census data from 1790 to 1930.^{[citation needed]}
IsoHunt the BitTorrent Tracker claim they have over 291.09 TBs of Torrent files.^{[citation needed]}
1.25 terabytes has been claimed as the capacity of a human being's functional memory, according to Raymond Kurzweil in The Singularity Is Near, p. 126. However, this is not widely accepted.
Apple Computer's Mac Pro (released August 2006) may be specified with internal storage of up to 3 Terabytes.
A Protein-coated disc (PCD) can hold 50 terabytes of data.

[edit] See also

tebibyte
terabit
binary prefix
orders of magnitude (data)
Terabyte is also the name of a fictional colonial termite that has become highly specialized in the documentary film The Future is Wild
Terabyte Interactive is also the name of a Macromedia Flash web design company based in Auckland, New Zealand. The company created the first CD-ROM pressed in New Zealand.[1]