IEC 80000-13:2008

IEC 80000-13
Edition 1.0 2008-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Quantities and units –
Part 13: Information science and technology

Grandeurs et unités –
Partie 13: Science et technologies de l'information

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IEC 80000-13
Edition 1.0 2008-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Quantities and units –
Part 13: Information science and technology

Grandeurs et unités –
Partie 13: Science et technologies de l'information

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
T
CODE PRIX
ICS 01.040.35 ISBN 2-8318-9625-8

– 2 – 80000-13 © IEC:2008
CONTENTS
FOREWORD.3
INTRODUCTION.5

0.1 Arrangements of the tables .5
0.2 Tables of quantities .5
0.3 Tables of units.5
0.3.1 General .5
0.3.2 Remark on units for quantities of dimension one, or dimensionless
quantities.6
0.4 Numerical statements in this International Standard .6

1 Scope.9
2 Normative references .9
3 Names, definitions and symbols .9
4 Prefixes for binary multiples .24

Bibliography.25

80000-13 © IEC:2008 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
QUANTITIES AND UNITS –
Part 13: Information science and technology

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
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indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 80000-13 has been prepared by IEC technical committee 25:
Quantities and units, and their letter symbols.
This standard cancels and replaces subclauses 3.8 and 3.9 of IEC 60027-2:2005.
The only significant change is the addition of explicit definitions for some quantities.
The text of this standard is based on the following documents:
FDIS Report on voting
25/371/FDIS 25/377/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – 80000-13 © IEC:2008
IEC 80000 consists of the following parts, under the general title Quantities and units:
Part 6: Electromagnetism
Part 13: Information science and technology
Part 14: Telebiometrics related to human physiology
The following parts are published by ISO:
Part 1: General
Part 2: Mathematical signs and symbols to be used in the natural sciences and technology
Part 3: Space and time
Part 4: Mechanics
Part 5: Thermodynamics
Part 7: Light
Part 8: Acoustics
Part 9: Physical chemistry and molecular physics
Part 10: Atomic and nuclear physics
Part 11: Characteristic numbers
Part 12: Solid state physics
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
80000-13 © IEC:2008 – 5 –
INTRODUCTION
0.1 Arrangements of the tables
The tables of quantities and units in ISO/IEC 80000 are arranged so that the quantities are
presented on the left-hand pages and the units on the corresponding right-hand pages.
All units between two full lines on the right-hand pages belong to the quantities between the
corresponding full lines on the left-hand pages.
Where the numbering of an item has been changed in the revision of a part of IEC 60027, the
number in the preceding edition is shown in parenthesis on the left-hand page under the new
number for the quantity; a dash is used to indicate that the item in question did not appear in
the preceding edition.
0.2 Tables of quantities
The names in English and in French of the most important quantities within the field of this
document are given together with their symbols and, in most cases, their definitions. These
names and symbols are recommendations. The definitions are given for identification of the
quantities in the International System of Quantities (ISQ), listed on the left hand pages of
Table 1; they are not intended to be complete.
The scalar, vectorial or tensorial character of quantities is pointed out, especially when this is
needed for the definitions.
In most cases only one name and only one symbol for the quantity are given; where two or
more names or two or more symbols are given for one quantity and no special distinction is
made, they are on an equal footing. When two types of italic letters exist (for example as with
ϑ and θ; φ and φ; a and a; g and g) only one of these is given. This does not mean that the
other is not equally acceptable. It is recommended that such variants should not be given
different meanings. A symbol within parenthesis implies that it is a reserve symbol, to be used
when, in a particular context, the main symbol is in use with a different meaning.
In this English edition the quantity names in French are printed in an italic font, and are
preceded by fr. The gender of the French name is indicated by (m) for masculine and (f) for
feminine, immediately after the noun in the French name.
0.3 Tables of units
0.3.1 General
The names of units for the corresponding quantities are given together with the international
symbols and the definitions. These unit names are language-dependent, but the symbols are
th
international and the same in all languages. For further information, see the SI Brochure (8
edition 2006) from BIPM and ISO 80000-1 (under preparation).
The units are arranged in the following way:
a) The coherent SI units are given first. The SI units have been adopted by the General
Conference on Weights and Measures (Conférence Générale des Poids et Mesures,
CGPM). The use of coherent SI units, and their decimal multiples and submultiples formed
with the SI prefixes are recommended, although the decimal multiples and submu
...