This document defines and provides examples for various metric prefixes used to modify units of digital information storage. It explains the etymology and defines the meaning of prefixes from pico to tera, along with their symbols. Examples are given for common storage capacities measured in kilobytes, megabytes, gigabytes and terabytes.

1. Measurements
in
Informatics.
Alba Corbacho
&
Sara Barrientos

2. PICO 10−12
Derived from the Spanish pico, meaning peak, beak, this
was one of the original 12 prefixes defined in 1960 when the
International System of Units was established.
Its symbol is p.
The radius of atoms range from 25 picometers (hydrogen) -
260 picometers (caesium).
A gamma ray wavelength is one pico.

3. NANO 10−9
The prefix is derived from the Greek νᾶνος, meaning
"dwarf", and was officially confirmed as standard in 1960.
Its symbol is n.
One nanometre is about the length that a fingernail grows in
a second.
The thickness of the DNA is 3 nanometres.

4. MICRO 10−6
Confirmed in 1960.
The symbol for the prefix comes from the Greek letter μ
(mu). It is the only SI prefix which uses a character not from
the Latin alphabet.
A clay particle is one μ.
The size of the influenza virus is about 0.8 to 1.2
micrometres.

5. MILI 10-3
Adopted in 1795.
The prefix comes from the Latin mille, meaning one
thousand (the plural is milia).
Its symbol is m.
A snow crystal is about 1 millimeter in diameter.

6. CENTI 10−2
Adopted in 1795.
Its symbol is c.
The prefix comes from the Latin centum, meaning hundred.
It is mainly used with the metre to express lengths in
centimetres.
A coffee bean is one centimetre.

7. DECI 10−1
Adopted in 1795.
The prefix comes from the Latin decimus, meaning tenth.
Its symbol is d.
A CD is about 12 centimeters or 1.2 decimeters.

8. DECA 101
The prefix was a part of the original metric system in 1795.
The term is derived from the Greek δέκα meaning "ten".
Its symbol is da.
The blue whale is approximately 3 decameters in length.

9. HECTO 102
It was adopted as a multiplier in 1795.
Comes from the Greek ἑκατόν hekaton, meaning hundred.
Its symbol is h.
The Eiffel Tower is 3 hectometres high.

10. KILOBYTE 103
It was originally adopted by Antoine Lavoisier's research
group in 1795, and introduced into the metric system in
France with its establishment in 1799.
The prefix kilo is derived from the Greek word χίλιοι (chilioi),
meaning "thousand".
Its symbol is kb.
In the past floppy disks were used. Each one had very little
capacity of kilobytes.

11. MEGABYTE 106
It was confirmed for use in the International System of Units
(SI) in 1960.
Mega comes from the Greek μέγας megas, meaning "great".
Its symbol is MB.
6 seconds of uncompressed CD audio.

12. GIGABYTE 109
The Oxford English Dictionary reports the earliest written
use of giga in this sense to be in the Reports of the IUPAC
14th Conference in 1947.
Giga is derived from the Greek word γίγας, meaning "giant“.
Its symbol is GB.
A hard disk capacity is 120 gigabytes.

13. TERABYTE 1012
The prefix tera was confirmed for use in the SI in 1960.
Tera is derived from Greek word τέρας teras, meaning
“monster”.
Its symbol is TB.
Video: Released in 2009, the 3D animated film Monsters vs.
Aliens used 100 TB of storage during development.