Quantities and units - Part 13: Information science and technology

In IEC 80000-13:2008, names, symbols and definitions for quantities and units used in information science and technology are given. Where appropriate, conversion factors are also given. International Standard IEC 80000-13 has been prepared by IEC technical committee 25: Quantities and units, and their letter symbols in co-operation with ISO/TC 12. 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.

Größen und Einheiten - Teil 13: Informationswissenschaft und -technik

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

La CEI 80000-13:2008 donne les noms, les symboles et les définitions de grandeurs et unités employées dans la science et les technologies de l'information. Des facteurs de conversion sont également indiqués, s'il y a lieu. La Norme internationale CEI 80000-13 a été établie par le comité d'études 25 de la CEI: Grandeurs et unités, et leurs symboles littéraux en collaboration avec le TC 12 de l'ISO. Cette norme annule et remplace les paragraphes 3.8 et 3.9 de la CEI 60027-2:2005. Le seul changement majeur est l'adjonction de définitions explicites pour certaines grandeurs.

Veličine in enote - 13. del: Informacijska znanost in tehnologija (IEC 80000-13:2008)

General Information

Status
Published
Publication Date
29-Jul-2008
Current Stage
6060 - Document made available
Due Date
30-Jul-2008
Completion Date
30-Jul-2008

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Standards Content (sample)

SLOVENSKI STANDARD
SIST EN 80000-13:2008
01-oktober-2008
9HOLþLQHLQHQRWHGHO,QIRUPDFLMVND]QDQRVWLQWHKQRORJLMD ,(&


Quantities and units - Part 13: Information science and technology (IEC 80000-13:2008)

Größen und Einheiten - Teil 13: Informationswissenschaft und -technik (IEC 80000-

13:2008)

Grandeurs et unités - Partie 13: Science et technologies de l'information (CEI 80000-

13:2008)
Ta slovenski standard je istoveten z: EN 80000-13:2008
ICS:
01.060 9HOLþLQHLQHQRWH Quantities and units
35.020 Informacijska tehnika in Information technology (IT) in
tehnologija na splošno general
SIST EN 80000-13:2008 en,fr

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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EUROPEAN STANDARD
EN 80000-13
NORME EUROPÉENNE
July 2008
EUROPÄISCHE NORM
ICS 01.040.35 Partially supersedes EN 60027-2:2007
English version
Quantities and units -
Part 13: Information science and technology
(IEC 80000-13:2008)
Grandeurs et unités - Größen und Einheiten –
Partie 13: Science et technologies Teil 13: Informationswissenschaft
de l'information und -technik
(CEI 80000-13:2008) (IEC 80000-13:2008)

This European Standard was approved by CENELEC on 2008-06-01. CENELEC members are bound to comply

with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard

the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on

application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other

language made by translation under the responsibility of a CENELEC member into its own language and notified

to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the

Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,

Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 80000-13:2008 E
---------------------- Page: 2 ----------------------
EN 80000-13:2008 - 2 -
Foreword

The text of document 25/371/FDIS, future edition 1 of IEC 80000-13, prepared by IEC TC 25, Quantities

and units, and their letter symbols, was submitted to the IEC-CENELEC parallel vote and was approved

by CENELEC as EN 80000-13 on 2008-06-01.
This European Standard supersedes Subclauses 3.8 and 3.9 of EN 60027-2:2007.

The only significant change is the addition of explicit definitions for some quantities.

The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2009-03-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2011-06-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice

The text of the International Standard IEC 80000-13:2008 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following note has to be added for the standard indicated:

IEC 60027-1 NOTE Harmonized as EN 60027-1:2006 (not modified).
__________
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- 3 - EN 80000-13:2008
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.

NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD

applies.
Publication Year Title EN/HD Year
IEC 60027-3 2002 Letter symbols to be used in electrical EN 60027-3 2007
technology -
Part 3: Logarithmic and related quantities,
and their units
IEC 60050-704 1993 International Electrotechnical Vocabulary - -
(IEV) -
Chapter 704: Transmission
IEC 60050-713 1998 International Electrotechnical Vocabulary - -
(IEV) -
Part 713: Radiocommunications: transmitters,
receivers, networks and operation
IEC 60050-715 1996 International Electrotechnical Vocabulary - -
(IEV) -
Chapter 715: Telecommunication networks,
teletraffic and operation
IEC 60050-721 1991 International Electrotechnical Vocabulary - -
(IEV) -
Chapter 721: Telegraphy, facsimile and data
communication
ISO/IEC 2382-16 1996 Information technology - Vocabulary - - -
Part 16: Information theory
---------------------- Page: 4 ----------------------
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
CODE PRIX
ICS 01.040.35 ISBN 2-8318-9625-8
---------------------- Page: 5 ----------------------
– 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

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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

the latter.

5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any

equipment declared to be in conformity with an IEC Publication.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

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.

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– 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.
---------------------- Page: 8 ----------------------
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

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 submultiples

are not explicitly mentioned.

b) Some non-SI units are then given, being those accepted by the International Committee

for Weights and Measures (Comité International des Poids et Mesures, CIPM), or by the

International Organization of Legal Metrology (Organisation Internationale de Métrologie

Légale, OIML), or by ISO and IEC, for use with the SI.
---------------------- Page: 9 ----------------------
– 6 – 80000-13 © IEC:2008

Such units are separated from the SI units in the item by use of a broken line between the

SI units and the other units.

c) Non-SI units currently accepted by the CIPM for use with the SI are given in small print

(smaller than the text size) in the “Conversion factors and remarks” column.

d) Non-SI units that are not recommended are given only in annexes in some parts of

ISO/IEC 80000. These annexes are informative, in the first place for the conversion

factors, and are not integral parts of the standard. These deprecated units are arranged in

two groups:
1) units in the CGS system with special names;
2) units based on the foot, pound, second, and some other related units.

e) Other non-SI units given for information, especially regarding the conversion factors, are

given in another informative annex.

0.3.2 Remark on units for quantities of dimension one, or dimensionless quantities

The coherent unit for any quantity of dimension one, also called a dimensionless quantity, is

the number one, symbol 1. When the value of such a quantity is expressed, the unit symbol 1

is generally not written out explicitly.
EXAMPLE
Refractive index n = 1,53 × 1 = 1,53

Prefixes shall not be used to form multiples or submultiples of this unit. Instead of prefixes,

powers of 10 are recommended.
EXAMPLE
Re = 1,32 × 10
Reynolds number

Considering that plane angle is generally expressed as the ratio of two lengths and solid

angle as the ratio of two areas, in 1995 the CGPM specified that, in the SI, the radian, symbol

rad, and steradian, symbol sr, are dimensionless derived units. This implies that the quantities

plane angle and solid angle are considered as derived quantities of dimension one. The units

radian and steradian are thus equal to one; they may either be omitted, or they may be used

in expressions for derived units to facilitate distinction between quantities of different kinds

but having the same dimension.
0.4 Numerical statements in this International Standard

The sign = is used to denote “is exactly equal to”, the sign ≈ is used to denote “is

approximately equal to”, and the sign := is used to denote “is by definition equal to”.

Numerical values of physical quantities that have been experimentally determined always

have an associated measurement uncertainty. This uncertainty should always be specified. In

this standard, the magnitude of the uncertainty is represented as in the following example.

EXAMPLE
l = 2,347 82(32) m
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80000-13 © IEC:2008 – 7 –

In this example, l = a(b) m, the numerical value of the uncertainty b indicated in parentheses

is assumed to apply to the last (and least significant) digits of the numerical value a of the

length l. This notation is used when b represents one standard uncertainty (estimated

standard deviation) in the last digits of a. The numerical example given above may be

interpreted to mean that the best estimate of the numerical value of the length l, when l is

expressed in the unit metre, is 2,347 82, and that the unknown value of l is believed to lie

between (2,347 82 – 0,000 32) m and (2,347 82 + 0,000 32) m with a probability determined

by the standard uncertainty 0,000 32 m and the probability distribution of the values of l.

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– 8 – 80000-13 © IEC:2008
– Blank page –
---------------------- Page: 12 ----------------------
80000-13 © IEC:2008 – 9 –
QUANTITIES AND UNITS –
Part 13: Information science and technology
1 Scope

In IEC 80000-13 names, symbols and definitions for quantities and units used in information

science and technology are given. Where appropriate, conversion factors are also given.

2 Normative references

The following referenced documents are indispensable for the application of this document.

For dated references, only the edition cited applies. For undated references, the latest edition

of the referenced document (including any amendments) applies.

IEC 60027-3:2002, Letter symbols to be used in electrical technology – Part 3: Logarithmic

and related quantities, and their units

IEC 60050-704:1993, International electrotechnical vocabulary – Part 704: Transmission

IEC 60050-713:1998, International electrotechnical vocabulary – Part 713: Radiocommuni-

cations: transmitters, receivers, networks and operation

IEC 60050-715:1996, International electrotechnical vocabulary – Part 715: Telecommuni-

cation networks, teletraffic and operation

IEC 60050-721:1991, International electrotechnical vocabulary – Part 721: Telegraphy, fac-

simile and data communication

ISO/IEC 2382-16:1996, Information technology – Vocabulary – Part 16: Information theory

3 Names, definitions and symbols

The names, definitions and symbols for quantities and units of information science and

technology are given in the tables on the following pages. Prefixes for binary multiples are

also given.
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– 10 – 80000-13 © IEC:2008
INFORMATION SCIENCE AND TECHNOLOGY QUANTITIES
Item No. Name Symbol Definition Remarks

13-1 traffic intensity number of simultaneously busy resources in a See IEC 60050-715, item

(801) particular pool of resources 715-05-02.
fr intensité (f) de
...

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