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[[SI Prefixes]] are not used in the computer world, things are a bit different:

== Commonly used ==

These prefixes are easily confused with [[SI Prefixes]].

{| {{border}}
! Symbol !! Prefix !! Factor         !! Factor           
|-
| P      || peta   || 2<sup>50</sup> || 1125899906842624 
|-
| T      || tera   || 2<sup>40</sup> || 1099511627776    
|-
| G      || giga   || 2<sup>30</sup> || 1073741824       
|-
| M      || Mega   || 2<sup>20</sup> || 1048576          
|-
| k      || kilo   || 2<sup>10</sup> || 1024             
|}

== IEC 60027-2 / IEEE 1541-2002 ==

IEC has adopted these prefixes to solve the confusion. These are not widely used (yet).

{| {{border}}
! Symbol !! Prefix !! Factor         !! Factor              
|-
| Yi     || yobi   || 2<sup>80</sup> || 1208925819614629174706176
|-
| Zi     || zebi   || 2<sup>70</sup> || 1180591620717411303424
|-
| Ei     || exbi   || 2<sup>60</sup> || 1152921504606846976 
|-
| Pi     || pebi   || 2<sup>50</sup> || 1125899906842624    
|-
| Ti     || tebi   || 2<sup>40</sup> || 1099511627776       
|-
| Gi     || gibi   || 2<sup>30</sup> || 1073741824          
|-
| Mi     || mebi   || 2<sup>20</sup> || 1048576             
|-
| Ki     || kibi   || 2<sup>10</sup> || 1024                
|}

''kibi originates from '''ki'''lo'''bi'''nary''

== Bits/Bytes ==

{| {{border}}
! Symbol !! Suffix !! Description
|-
| b      || bit    || one binary digit, value 0 or 1
|-
| B      || Byte   || 4-10 bits, but in most cases 8 bits
|-
| o      || octet  || 8 bits
|}

== Examples ==

{| {{border}}
! Symbol   !! Prefix
|-
| 1 kB     || 1024 bytes ''(but 1000 bytes according to [[SI Prefixes|SI]])''
|-
| 1 KiB    || 1024 bytes (IEC)
|-
| 10 Mb/s  || 10485760 bits/second = 1310720 bytes/second ''(but 1250000 bytes/seconds according to [[SI Prefixes|SI]])''
|-
| 10 Mib/s || 10485760 bits/second = 1310720 bytes/second (IEC)
|}

== Standards ==
* IEC 60027-2:2005
* IEEE 1541-2002

== See also ==
* [[SI Prefixes]]

== Contributions ==
* [[User:Joakim|Joakim Ögren]]
* [mailto:hkazemi@geocities.com Haudy Kazemi]
* [mailto:kweber@ix.urz.uni-heidelberg.de Knut Kristan Weber]
* [mailto:daniel@silicon.nu Daniel Nilsson]

== Sources ==
* [http://www.iec.ch/zone/si/si_bytes.htm IEC: Prefixes for binary multiples]
* [http://physics.nist.gov/cuu/Units/binary.html NIST: Prefixes for binary multiples]

[[Category:Table]]