ISO/IEC 16509:1999

Information technology — Year 2000 terminology

1.1 Scope This standard identiÞes terms and concepts pertinent to the resolution of the Year 2000 issue, including the rollover from the year 1999 to 2000, incorrect recognition of leap years, and values in date Þelds used for non-date purposes, and provides deÞnitions of these terms and descriptions of these concepts. This standard does not speciÞcally address operating system anomalies such as might occur in the year 2038. 1.2 Purpose This standard provides a common lexicon with descriptions and deÞnitions for the Year 2000 issue. These descriptions and deÞnitions may be applied in whole or in part depending on the requirement. This standard is composed of a DeÞnitions Clause (3), a Concepts Clause (4), and two Annexes (A and B). 1.2.1 Concepts A concept is a set of interrelated ideas pertaining to the Year 2000 issue. This standard offers a description of these concepts. This is not an exhaustive list. 1.2.2 DeÞnitions These are focused meanings of terms fundamental to the resolution of the Year 2000 issue. 1.2.3 Annex A This annex outlines remediation techniques currently being used to make system elements Year 2000 compliant. This list of techniques is not exhaustive. It presents only those techniques acknowledged as having gained a signiÞcant amount of industry consensus. Along with the techniques is a list of supporting terms and their explanation. In addition, the annex brießy explains the role of special dates in the development of solutions for the Year 2000 problem. This annex is informative. 1.2.4 Annex B This is a bibliography listing other related publications. 1.3 Conformance Vendors who claim that their products conform to this standard declare that their use of the term ÒYear 2000 CompliantÓ is in accordance with the deÞnition in this standard.

Technologie de l'information — Terminologie de l'an 2000

General Information

• Status: Published
• Publication Date: 20-Oct-1999
• ICS: 01.040.35 - Information technology (Vocabularies)
• ICS: 35.060 - Languages used in information technology
• Technical Committee: ISO/IEC JTC 1/SC 22 - Programming languages, their environments and system software interfaces
• Drafting Committee: ISO/IEC JTC 1/SC 22 - Programming languages, their environments and system software interfaces
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 07-Jul-2021

Relations

• Consolidated By: ISO 5402-1:2011 - Leather — Determination of flex resistance — Part 1: Flexometer method
• Effective Date: 06-Jun-2022

Standards Content (Sample)

ISO/IEC 16509:1999(E)
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Abstract: This standard provides concepts, definitions, remediation techniques, and other support-
ing terms fundamental to a lexicon for Year 2000 terminology. It addresses key topics pertinent to
the development of resolutions to the Year 2000 problem. The core of this standard is the definitions
Clause which contains the definition for Year 2000 compliance. Two critical aspects of this definition
are: first, the acknowledgment of the significance of documentation associated with technology,
and, second, the recognition that compliance is a two-way street, i.e., the proper exchange of date
data is paramount for technology to remain compliant.
Keywords: date exchange, remediation techniques, Year 2000 compliant
The Institute of Electrical and Electronics Engineers, Inc.
3 Park Avenue, New York, NY 10016-5997, USA
Copyright © 1999 by the Institute of Electrical and Electronics Engineers, Inc.
All rights reserved. Published 7 October 1999. Printed in the United States of America.
Print: ISBN 0-7381-1803-6 SH94784
PDF: ISBN 0-7381-1804-4 SS94784
No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior
written permission of the publisher.

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ANSI/IEEE 2000.1-1998
IEEE Standards documents are developed within the IEEE Societies and the Standards Coordinat-
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time a standard is approved and issued is subject to change brought about through developments in
the state of the art and comments received from users of the standard. Every IEEE Standard is sub-
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ii

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ISO/IEC 16509:1999(E)
International Standard ISO/IEC 16509:1999(E)
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission)
form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC
participate in the development of International Standards through technical committees established by the
respective organization to deal with particular fields of technical activity. ISO and IEC technical committees
collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in
liaison with ISO and IEC, also take part in the work.
In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote.
International Standard ISO/IEC 16509 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information
technology, Subcommittee SC 22, Programming languages, their environments and system software interfaces.
Annexes A to C of this International Standard are for information only.
International Organization for Standardization/International Electrotechnical Commission
Case postale 56 � CH-1211 Genève 20 � Switzerland
iii

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ANSI/IEEE 2000.1-1998
This introduction provides background on the rationale used to develop this international standard. This
information is meant to aid in the understanding and usage of this standard.
This international standard addresses the key industry concern over the existence of multiple terms and
lexicons that carry varied meanings. IEEE has designed this standard to assist individuals and organiza-
tions in their efforts to develop Year 2000 solutions. Having a base-line set of terms and deÞnitions that
can serve as a foundation for such efforts is vital.
Participants
PASC Sponsor Executive Committee
Chair: Lowell G. Johnson
Vice-Chair: Joseph Gwinn
Functional Chairs: Andrew Josey
Jay Ashford
Curtis Royster
Secretary: Nick Stoughton
At the time the IEEE Portable Applications Standards Committee revised this standard, the Year 2000 Termi-
nology Working Group had the following membership:
Kevin Lewis, Technical Editor
Tim Harris
Michael Aisenberg James Murray
JoAnn Henderson
Steve Allen John Napier
Richard Holleman
Michael Berens Alan Peltzman
Vincent Hung
Leonard Brush Carolyn Price
James D. Isaak
George Cherry Bill Pritchett
Petr Janecek
Cory Claymon Bill Putnam
Margaret Jedlicka
Joseph K. Clema Larry Schwartz
Andrew Josey
Robert Cohen Philip Simons
Yong Kim
Johnetta Colbert Terrill J. Slocum
C. W. Klein
Eldon Colby Nick Stoughton
Thomas Koenig
Donald Cragun Robert Swartz
Cheryl Lai
John Davies Keith Thurston
Rex Lint
Christina Drukala John Tyler
Mickey Lynn
Amy Fliegelman-Olli Roger Tyler
Austin J. Maher
Trutz Foelsche Richard Vasquez
Robert Martin
Lee Gallagher Michael Wheatley
Roger Martin
Robert Gniewkowski Laurence Wolfe
Richard McLean
Debbie Goldberg Dave Wong
Joeseph M. Gwinn Gary Young
iv Copyright © 1999 IEEE. All rights reserved.

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The following persons were on the balloting committee:
Leon A. Kappelman
Ida M. Berchtold Curtis Royster
Judith S. Kerner
Adam Block Alan Russel
Lorraine C. Kevra
Mark Brown Michael D. Shapiro
Thomas Koenig
Joseph K. Clema Keith Shillington
Kenneth C. Kung
Donald Cragun Terrill J. Slocum
Thomas M. Kurihara
Philip H. Enslow William R. Smith
Kevin Lewis
Michel Gien Sandra Swearingen
Austin J. Maher
Lawrence M. Gunther Andrew D. Tait
James W. Moore
Charles E. Hammons Roger Tyler
Finnbarr P. Murphy
Andy Harrison Michael W. Vannier
John Napier
Barry Hedquist Dale W. Way
James T. Oblinger
Jim D. Isaak Thomas Williams
Marc A. Pearl
Richard Jaenicke Darren Wolf
Alan Peltzman
Jerry L. Johnson Paul A. Wolfgang
Roy Reed
Lowell G. Johnson Jordan S. Wouk
Francois Riche
Andrew Josey Oren Yuen
When the IEEE-SA Standards Board approved this standard on 25 June 1998, it had the following
membership:
Richard J. Holleman, Chair Donald N. Heirman, Vice Chair
Judith Gorman, Secretary
Satish K. Aggarwal James H. Gurney L. Bruce McClung
Clyde R. Camp Jim D. Isaak Louis-Franois Pau
James T. Carlo Lowell G. Johnson Ronald C. Petersen
Gary R. Engmann Robert Kennelly Gerald H. Peterson
Harold E. Epstein E. G. ÒAlÓ Kiener John B. Posey
Jay Forster* Joseph L. KoepÞnger* Gary S. Robinson
Thomas F. Garrity Stephen R. Lambert Hans E. Weinrich
Ruben D. Garzon Jim Logothetis Donald W. Zipse
Donald C. Loughry
*Member Emeritus
Noelle D. Humenick
IEEE Standards Project Editor
Note that editorial changes were made to the IEEE standard to accomodate concerns raised during the ISO/
IEC/JTC 1 balloting process. These are indicated in the text by a change bar (such as shown at the left of this
paragraph.)
Copyright © 1999 IEEE. All rights reserved. v

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Contents
1. Overview. 1
1.1 Scope. 2
1.2 Purpose. 2
1.3 Conformance. 3
2. References. 3
3. Definitions. 3
4. Concepts. 3
4.1 Valid date interval (also known as compliance date range) . 3
4.2 Time horizon to failure (also known as event horizon) . 4
4.3 Year 2000 life cycle. 4
Annex AÑTechniques, terms, and special dates. 5
Annex BÑBibliography . 8
vi Copyright © 1999 IEEE. All rights reserved.

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Information technologyÑYear 2000
terminology
1. Overview
The Year 2000 issue appears to be a simple problem that is intuitively understood. However, when examined
closely, the solutions are varied and complex in nature. The essence of this problem is the representation of
the year as a two-digit number in hardware and software elements of computer systems and other technolo-
gies. This representation may, for example, cause hardware or software malfunctions to occur when a system
date or application date crosses the year 2000 boundary (whether that is the actual arrival of the date or for
date processing purposes) or when the system or application must refer to a date that occurs on, before, or
after 1 January 2000. These malfunctions can include the following:
Ñ Incorrect arithmetic calculation, comparison, sorting, or sequencing resulting in the failure of logical,
relational, and set-membership operations;
Ñ Incorrect recognition of leap year;
Ñ Conßict with values in data Þelds used for non-date purposes, e.g., Òno date provided,Ó or Ònever
expiresÓ; and
Ñ Date data Þeld overßow.
The two-digit date may not be the sole cause of these malfunctions. They may also result from poor pro-
gramming practices or a lack of full understanding of the Gregorian calendar. The consequences of these
malfunctions could range from immediate system failures to more insidious long-term data corruptions.
The impact of the Year 2000 problem is potentially signiÞcant to virtually any segment of the global digital
infrastructure and the economies it supports. Among the environments in which critical applications may be
affected by Year 2000 issues are:
Ñ Bio-medical
Ñ Telecommunications/transportation
Ñ Finance/banking
Ñ Aviation/aerospace
Ñ National security/law enforcement
Ñ Other critical infrastructure
As this standard is being prepared, many organizations are in various stages of addressing this problem.
Some are just beginning to assess the impact on their own information technology (IT) environments. Others
1

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ISO/IEC 16509: 1999
IEEE Std 2000.1-1998 INFORMATION TECHNOLOGYÑ
have already begun to implement solutions. The rising need for solutions has created a market environment
wherein there are a growing number of organizations offering such solutions. These organizations have also
created a diverse set of terms. Many of the terms may seem similar, but will actually have multiple meanings
within differing environments, which brings the potential for confusion to what should be an easily under-
stood problem.
This standard identiÞes common terms, deÞnitions, and related concepts that have broad applicability to this
area of work. Those presented herein may be applied wholly or in part to Þt a speciÞc requirement.
A lexicon within which the common terms, deÞnitions, and related concepts are understood is vital. The IT
industryÕs use of the terms deÞned in this standard will minimize confusion. In addition, having common
terms, deÞnitions, and related concepts will speed the development of urgently needed solutions. This stan-
dard describes what these terms, deÞnitions, and related concepts mean, not how to implement or verify Year
2000 compliance.
It is not the intent of this standard to specify how Year 2000 compliance should be implemented or veriÞed.
1.1 Scope
This standard identiÞes terms and concepts pertinent to the resolution of the Year 2000 issue, including the
rollover from the year 1999 to 2000, incorrect recognition of leap years, and values in date Þelds used for
non-date purposes, and provides deÞnitions of these terms and descriptions of these concepts.
This standard does not speciÞcally address operating system anomalies such as might occur in the year
2038.
1.2 Purpose
This standard provides a common lexicon with descriptions and deÞnitions for the Year 2000 issue. These
descriptions and deÞnitions may be applied in whole or in part depending on the requirement.
This standard is composed of a DeÞnitions Clause (3), a Concepts Clause
...