Software Standards

Integrating Standards

Team members should be involved in the development of product standards.

• standards documents should include the rationale behind each standardization decision

Standards should be reviewed and modified to reflect changing technologies.

• standards documents should be dynamic, not static
• but it must be decided which standards cannot change, which are subject to revision and which do not apply to a particular project

Software tools should be provided to support the standards being used.

• this is probably the most important factor with respect to standards acceptance

Who Writes Standards?

Standards are difficult and time-consuming to create and administer. There are many national and international standards organizations.

Certain organizations (usually governments) insist on contractors following their own standards.

What are ISO, ITU, CCITT, ANSI, ...?

Many countries have national standards bodies where experts from industry and universities develop standards for all kinds of engineering problems. Among them are, for instance,

     ANSI     American National Standards Institute       USA
     DIN      Deutsches Institut fuer Normung             Germany
     BSI      British Standards Institution               United Kingdom
     AFNOR    Association francaise de normalisation      France
     UNI      Ente Nazionale Italiano di Unificatione     Italy
     NNI      Nederlands Normalisatie-instituut           Netherlands
     SAA      Standards Australia                         Australia
     SANZ     Standards Association of New Zealand        New Zealand
     NSF      Norges Standardiseringsforbund              Norway
     DS       Dansk Standard                              Denmark
     

The International Organization for Standardization, ISO, in Geneva is the head organization of all these national standardization bodies (from some 100 countries, one from each country).

It is a non-governmental organization and was established in 1947.

ISO's work results in international agreements which are published as International Standards.

"ISO" is not an acronym for the organization in any language. It's a wordplay based on the English initials and the Greek word isos, meaning "equal ", which is the root of the prefix "iso-" that occurs in a host of terms, such as " isometric " (of equal measure or dimensions).

In addition, the name has the advantage of being valid in each of the organization's three official languages - English, French and Russian.

Together with the International Electrotechnical Commission, IEC, ISO concentrates its efforts on harmonizing national standards all over the world. The results of these activities are published as ISO standards.

the metric system of units, international stationery sizes, all kinds of bolt nuts, rules for technical drawings, electrical connectors, security regulations, computer protocols, file formats, bicycle components, ID cards, programming languages, and International Standard Book Numbers (ISBN).

Over 10,000 ISO standards have been published so far.

Within ISO, ISO/IEC Joint Technical Committee 1 (JTC1) deals with information technology.

Especially relevant to computing are

• ITU-T V series of recommendations on modems (e.g. V.32, V.42),
• the X series on data networks and OSI (e.g. X.25, X.400),
• the I and Q series that define ISDN,
• the Z series that defines specification and programming languages (SDL, CHILL),
• the T series on text communication (teletex, fax, videotext, ODA)
• H series on digital sound and video encoding.

ISO Standards Relevant to Computing

ISO 646    Good ol' 7-bit ASCII with national variants 

ISO 2022   ESC sequences for switching between various character sets 

ISO 2382   Information technology -- Vocabulary 

ISO 3166   Codes for the representation of names of countries. 

           This standard defines a 2-letter, a 3-letter and a numeric 
           code for each country on this planet. 

              US/USA/840=United States 
              DE/DEU/276=Germany
              GB/GBR/826=United Kingdom
              FR/FRA/250=France

           The 2-letter codes are well known in the Internet as top-level 
           domain names. The 3-letter versions are often used at 
           international sports events. 

ISO 4217   Codes for the representation of currencies and funds 

ISO 5218   Representation of human sexes 

           Sex is represented by a one-character language independent 
           numerical code: 

              0=not known
              1=male
              2=female
              9=not specified 

           The standard also specifies, that "no significance 
           is to be placed on the fact that 'Male' is coded '1' and 
           'Female' is coded '2'.  This standard was developed based 
           upon predominant practice of the countries involved and does 
           not convey any meaning of importance, ranking or any other 
           basis that could imply discrimination." :-) 

ISO 6429   ASCII Control Codes, also known as VT100/VT320/ANSI escape 
           sequences 

ISO 6709   Representation of latitude, longitude and altitude of 
           geographic positions 

ISO 8601   Representation of dates and times. 

           This standard defines a lot of details of the calendar. 
           E.g. the ISO definition of the week numbers is that the 
           first day (day number 1) of a week is Monday and that the 
           first week in a year (week number 1) is the week that includes 
           the first Thursday in January, i.e. the first week that has at 
           least four days in January. 

           Other definitions are, e.g., that hours of a day are counted 
           from 0 to 24 and that the international notation of dates is the 
           Bigendian format year-month-day, e.g. 1993-04-17 and that for 
           time is 20:36:04. 

           There are also string formats for computer applications 
           specified that have to represent date and time in files 
           and protocol packets. 

ISO 8632   Computer Graphics Metafile (CGM). This standard defines 
           a file format for 2D vector graphics. Part 1 defines the 
           graphic elements (lines, filled polygons, text, colors, ...)
           that may appear in a CGM and the other parts define 3 different 
           encodings for these graphic elements.

ISO 8652   The Ada programming language 

ISO 8859   Several 8-bit ASCII extensions. Especially ISO 8859-1, the 
           "Latin alphabet No. 1" has become widely implemented and may 
           already be seen as the de-facto standard ASCII replacement. 
               ISO 8859-1     west European languages (Latin-1) 
               ISO 8859-2     east European languages (Latin-2) 
               ISO 8859-3     other Latin languages (Latin-3) 
               ISO 8859-4     north European languages (Latin-4) 
               ISO 8859-5     Latin/Cyrillic 
               ISO 8859-6     Latin/Arabic 
               ISO 8859-7     Latin/Greek 
               ISO 8859-8     Latin/Hebrew 
               ISO 8859-9     Latin-1 modification for Turkey (Latin-5) 
               ISO 8859-10    Baltic countries (under preparation) 

ISO 8879   Standard Generalized Markup Language (SGML), a format 
           for storing documents together with their logical structure 
           and perhaps layout information in a standardized way. 

ISO 9127   User documentation and cover information for consumer 
           software packages 

ISO 9592   Programmer's Hierarchical Interactive Graphics Interface 
           (PHIGS)

ISO 9593   PHIGS Language Bindings (Fortran, Pascal, Ada, C)

ISO 9541   Font and Character Information Interchange 

ISO 9636   Graphical device interfaces 

ISO 9660   CD-ROM volume and file structure 

ISO 9899   The C programming language 

ISO 9945   UNIX style system calls and shell commands (POSIX)

ISO 10646  A 32-bit character set called UCS containing (nearly) all 
           characters used on this planet that will hopefully solve 
           most of the character set troubles with computers one day. 
           Today only the 16-bit subset UCS-2 has been defined, also 
           known as 'Unicode' that is expected to become pretty 
           popular soon and will be supported by Windows NT, Plan 9 
           and other new operating systems. 

ISO 10744  HyTime -- A hypertext/multimedia extension to SGML 

International standardization: What does it achieve?

Industry-wide standardization is a condition existing within a particular industrial sector when the large majority of products or services conform to the same standards.

It results from consensus agreements reached between all economic players in that industrial sector - suppliers, users, and often governments.

The aim is to facilitate trade, exchange and technology transfer through:

• enhanced product quality and reliability at a reasonable price,
• improved health, safety and environmental protection, and reduction of waste,
• greater compatibility and interoperability of goods and services,
• simplification for improved usability,
• reduction in the number of models, and thus reduction in costs,
• increased distribution efficiency, and ease of maintenance.

Assurance of conformity can be provided by producers' declarations, or by audits carried out by independent bodies.

Who makes up ISO?

A member body of ISO is the national body "most representative of standardization in its country". It follows that only one such body for each country is accepted for membership.

The member bodies have four principal tasks:

1. informing potentially interested parties in their country of relevant international standardization opportunities and initiatives,
2. organizing so that a concerted view of the country's interests is presented during international negotiations leading to standards agreements,
3. ensuring that a secretariat is provided for those ISO technical committees and subcommittees in which the country has an interest,
4. providing their country's share of financial support for the central operations of ISO, through payment of membership dues.

The technical work of ISO is highly decentralized, carried out in a hierarchy of some 2,700 technical committees, subcommittees and working groups.

What does an ISO standard look like?

It can be anything from a four-page document to a 1000-page tome, including twice the weight of the standard itself in informative annexes. It may contain symbols, definitions, diagrams, codes, test methods, etc.

How are ISO standards developed?

ISO standards are developed according to the following principles:

• Consensus

  The views of all interests are taken into account: manufacturers, vendors and users, consumer groups, testing laboratories, governments, engineering professions and research organizations.

• Industry-wide

  Global solutions to satisfy industries and customers worldwide.

• Voluntary

  International standardization is market-driven and therefore based on voluntary involvement of all interests in the market-place.

There are three main phases in the ISO standards development process.

• The need for a standard is usually expressed by an industry sector, which communicates this need to a national member body. The latter proposes the new work item to ISO as a whole.
• Once the need for an International Standard has been recognized and formally agreed, the first phase involves definition of the technical scope of the future standard.
  • This phase is usually carried out in working groups which comprise technical experts from countries interested in the subject matter.
• Once agreement has been reached on which technical aspects are to be covered in the standard, a second phase is entered during which countries negotiate the detailed specifications within the standard.
  • This is the consensus-building phase.
• The final phase comprises the formal approval of the resulting draft International Standard.
  • the acceptance criteria stipulate approval by two-thirds of the ISO members that have participated actively in the standards development process, and approval by 75% of all members that vote,
• The agreed text is then published as an ISO International Standard.

Most standards require periodic revision. Several factors combine to render a standard out of date:

• technological evolution,
• new methods and materials,
• new quality and safety requirements

To take account of these factors, ISO has established the general rule that all ISO standards should be reviewed at intervals of not more than five years.

• On occasion, it is necessary to revise a standard earlier.

How is ISO's work financed?

The financing of the Central Secretariat derives from member body subscriptions (70%) and revenues from the sale of the Organization's standards and other publications (30%).

The subscriptions required of member bodies is calculated on the basis of economic indicators of gross national product (GNP), and value of imports and exports. The value of the subscription unit is set each year by the ISO Council.