WELL - World-Wide Lotos

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[a translation of a version of this page has been created for Russian (Leonid Popov)]

Orange Dot Lotos Origins
Orange Dot Meanings for Lotos
Orange Dot Lotos Institutions
Orange Dot Lotos Projects
Orange Dot Lotos Tools
Orange Dot Lotos Documentation
Orange Dot Lotos Applications
Orange Dot Lotos Bibliography

Lotos Origins

Lotos (Language Of Temporal Ordering Specification) is an FDT (Formal Description Technique) developed as an international standard (ISO/IEC 8807). FDTs were originally developed by ISO (International Organization for Standardization) to support standardisation of OSI (Open Systems Interconnection). However, FDTs have are generally applicable to a wide variety of systems.

The majority of ISO standards are written in natural language, which is difficult to make precise and unambiguous. It was recognised that there could be problems in achieving a uniform understanding of standards. How could ISO ensure that thousands of implementers world-wide would design from standards in a compatible way? Could the problems of natural language description be avoided, particularly for those reading a standard that is not in their native language? Who would provide the definitive interpretation of a standard when its original developers had dispersed?

The scale and complexity of OSI led to the formation of a group to standardise formal specification languages for OSI. These languages - or FDTs as they became known - were developed to provide the basis for unambiguous definitions of standards. The aim was to help:

The standardisation of FDTs for OSI was entrusted to ISO committee SC21/WG1 (OSI Architecture). When an FDT group was set up in ISO, it was split into three subgroups: A on specification architecture, B on Estelle and C on Lotos. In parallel, work on formal techniques in telecommunications had already begun in CCITT (International Telephone and Telegraph Consultative Committee), which later became ITU-T (International Telecommunications Union). A standard for SDL (Specification and Description Language) was evolved over the period from 1976 to 1992 by committee SGX/WP3. In 1986, a collaboration was established with ISO on the development of formal techniques. This led to joint recognition of Estelle, Lotos and SDL as the official FDTs for use in standardisation. There was also cooperation on guidelines and tutorials for the use of FDTs.

Lotos Standardisation

Lotos is standardised as ISO/IEC 8807. It was initially based on the formal specification language CCS (Calculus of Communicating Systems). Some notation and concepts were later introduced from the similar CSP (Communicating Sequential Processes). Data typing was considered only later in the development of Lotos. The abstract data type language Act One was adapted to allow formal specification of data types in Lotos. An International Standard for Lotos was completed after 9 years' work! Surprisingly, Lotos was one of the first pieces of mathematics to be standardised internationally.

An interesting feature of Lotos is that architectural principles were emphasised throughout its development. For example, to make sure that Lotos was suitable for application to OSI, it was applied to the specification of basic concepts from this architecture. Larger case studies were also undertaken during development of the language to check that Lotos scaled up satisfactorily to deal with complex standards. Although Lotos was originally applied to OSI, it has now been applied more widely to sequential, concurrent, and distributed systems generally.

Later standardisation work leter to E-Lotos (Enhancements to Lotos), standardised as ISO/IEC 15437. However, E-Lotos was never widely used - largely due to limited tool support.

Meanings for Lotos

According to Webster's New Collegiate Dictionary, Lotos means a fruit considered to cause indolence and dreamy contentment. This refers to The Lotos Eaters poem by Sir Alfred Lord Tennyson:

Let us swear an oath, and keep it with an equal mind,
In the hollow Lotos-land to live and lie reclined.

The name LOTOS lends itself to acronyms (in English at least). Here are a few general ones by various people:

Orange Dot Language Of Temporal Ordering Specification (officially)
Orange Dot Lots Of Terribly Obscure Symbols
Orange Dot Let's Obfuscate This Obvious Specification
Orange Dot Language Of Thousands Of Styles

LOTOS also has some amusing anagrams in English:

Orange Dot LOTS O' (since Lotos has lots o' good ideas)
Orange Dot O, LOST! (as said to or by Lotos beginners)
Orange Dot SOTOL (a lily-like plant resembling the Lotos)
Orange Dot STOOL (a portable support for specifiers)
Orange Dot TOOLS (an indispensable aid for specifiers)

Jan de Meer (then with HMI, Berlin) recalls that he attended the Deutsches Forschungsnetz DFN conference in Darmstadt, November 1983. During this event, he and others including Günther Karjoth (IBM Zurich) and Ed Brinksma (University of Twente) had dinner in a Chinese restaurant called the 'Lotos'. They were delighted to discover the restaurant name corresponded to the language under development at the time (which was previously known as the 'Temporal Ordering Specification Language'). At the conference, Jan made use of the Chinese lotus blossom and lotus character in his presentation.

Much of the Lotos development work was undertaken at the University of Twente (Netherlands), though with contributions from many organisations. Papers on Lotos also figured prominently in the early FORTE (Formal Techniques) conferences. As a result, Ken Turner (University of Stirling) observed that TWENTE was half of FORTE.

Lotos Institutions

Lotos has been used world-wide. Institutions known to the author to have used Lotos at one time or another include:
Orange Dot Brussels University (BE)
Orange Dot ENST (Ecole National Supérieur des Télécommunications, FR)
Orange Dot Erlangen-Nürnberg University (DE)
Orange Dot ESTEC (European Space Technology Centre, NL)
Orange Dot Glasgow University (UK)
Orange Dot GMD (Gesellschaft für Mathematik und Datenverarbeitung, now Fraunhofer Fokus, DE)
Orange Dot Helsinki University (FI)
Orange Dot INRIA Rhône-Alpes (FR)
Orange Dot Liège University (BE)
Orange Dot Lisbon New University (PT)
Orange Dot Polytechnic University of Madrid (ES)
Orange Dot Ottawa University (CA)
Orange Dot Pisa National Research Council (IT)
Orange Dot Osaka University (JP)
Orange Dot Royal Holloway and Bedford New College (UK)
Orange Dot Santa Catarina Federal University (BR)
Orange Dot SERI (Software Engineering Research Institute, KR)
Orange Dot Stirling University (UK)
Orange Dot Sussex University (UK)
Orange Dot SICS (Swedish Institute of Computer Science, SE)
Orange Dot Twente University (NL)
Orange Dot Ulster University (UK)

Lotos Projects

Lotos-related projects known to the author to have web pages are as follows:

Orange Dot ANISE (Architectural Notions in Service Engineering, UK)
Orange Dot CONFORMED (Conformed of Radiological/Medical Devices, UK)
Orange Dot CRESS (Communication Representation Employing Systematic Specification, UK)
Orange Dot DIET (Developing Implementation and Extending Theory - A Symbolic Approach to Reasoning about Lotos, UK)
Orange Dot DILL (Digital Logic in Lotos, UK)
Orange Dot EASEL (Evaluating And Standardising Enhanced Lotos, UK/ES)
Orange Dot EUCALYPTUS/INRIA Rhône-Alpes (FR)
Orange Dot FORMOSA (Formalisation of ODP Systems Architecture, UK)
Orange Dot Further Verification Techniques for Lotos (UK)
Orange Dot MUSTARD (Multiple-Use Specification Testing and Refusal Description, UK)
Orange Dot SPLICE (Specification using Lotos for an Interactive Customer Environment, UK)
Orange Dot Temporal Aspects of Verification of Lotos Specifications (UK)
Orange Dot Verification Techniques for Lotos (UK)
Orange Dot VASY (Validation of Systems, FR)

Lotos Tools

Orange Dot INRIA Rhône-Alpes VASY (FR):
    Yellow Dot CADP (Cæsar Aldébaran Development Package)
    Yellow Dot TRAIAN (E-Lotos Compiler - currently excluding behaviour)

Orange Dot Polytechnic University of Madrid (ES):
    Yellow Dot Topo (Toolset for Product Realisation with Lotos)

Orange Dot University of Stirling (UK)
    Yellow Dot Lotos Utilities

Orange Dot University of Twente (NL):
    Yellow Dot SMILE (SyMbolic Interactive Lotos Execution)

Lotos Documentation

Major publications about Lotos include:

Orange Dot Tommaso Bolognesi, Jeroen van de Lagemaat and Chris A. Vissers, editors. The LotosPHERE Project. Kluwer Academic Publishers, London, UK, 1995.
Orange Dot Peter H. J. van Eijk, Chris A. Vissers and Michel Diaz, editors. The Formal Description Technique Lotos: Results of the Esprit Sedos Project. Elsevier Science, Amsterdam, Netherlands, 1989.
Orange Dot ISO. Information Processing Systems - Open Systems Interconnection - Lotos - A Formal Description Technique based on the Temporal Ordering of Observational Behaviour. ISO/IEC 8807, International Organisation for Standardization, Geneva, Switzerland, 1989.
Orange Dot ISO. Information Technology - Enhancements to Lotos (E-Lotos). ISO/IEC 15437, International Organisation for Standardization, Geneva, Switzerland, 2001.
Orange Dot ISO. Information Processing Systems - Open Distributed Processing - ELotos - Extended Lotos. Committee Draft, International Organisation for Standardization, Geneva, Switzerland, May 1998.
Orange Dot Kenneth J. Turner, editor. Using Formal Description Techniques - An Introduction to Estelle, Lotos and SDL. Wiley, New York, USA, January 1993.

Online material includes:

Orange Dot Lotos Bibliography (online)
Orange Dot Lotos Bibliography (BibTeX)
Orange Dot Lotos Course for Users
Orange Dot Lotos News (somewhat dated)
Orange Dot Lotos Tutorials
Orange Dot Lotos Syntax

Lotos Applications

Although Lotos was specifically developed to support OSI, there is nothing in the language that limits it to this application. Lotos sites known to the author to have online case studies are:

Orange Dot INRIA Rhône-Alpes (FR):
Orange Dot University of Stirling (UK)

The following is a classification of application areas with some representative references. See the Lotos bibliography for details of the citations.

Orange Dot bus architecture:
    Yellow Dot [Azema-Drira-Vernadat-1990]
    Yellow Dot [Carchiolo-Faro-Mirabella-Pappalardo-Scollo-1986]
    Yellow Dot [Chehaibar-Garavel-Mounier-Tawbi-Zulian-1996]
    Yellow Dot [Sighireanu-Mateescu-1997]

Orange Dot conformance testing:
    Yellow Dot [Cavalli-Kim-Maigron-1994]
    Yellow Dot [Dubuc-vonBochmann-Bellal-Saba-1990]
    Yellow Dot [ElGendy-2003a]
    Yellow Dot [Gueraichi-Logrippo-1989b]
    Yellow Dot [Jard-Jeron-2005]
    Yellow Dot [Langerak-1989]
    Yellow Dot [Leduc-1991b]
    Yellow Dot [Tretmans-1989]
    Yellow Dot [Tripathy-Sarikaya-1991]
    Yellow Dot [Wezeman-1989]

Orange Dot CIM (Computer Integrated Manufacturing):
    Yellow Dot [Biemans-Blonk-1986]
    Yellow Dot [McClenaghan-1992a]

Orange Dot DTP (Distributed Transaction Processing):
    Yellow Dot [Widya-vanderHeijden-Riddoch-1990]

Orange Dot embedded systems:
    Yellow Dot [Clark-1991b]
    Yellow Dot [Clark-1992a]
    Yellow Dot [Pecheur-1992]

Orange Dot feature interaction:
    Yellow Dot [Bouma-Zuidweg-1993]
    Yellow Dot [Boumezbeur-Logrippo-1992]
    Yellow Dot [Faci-1995]
    Yellow Dot [Faci-Logrippo-1993b]
    Yellow Dot [Faci-Logrippo-1994]
    Yellow Dot [Faci-Logrippo-1996]
    Yellow Dot [Fu-Harnois-Logrippo-Sincennes-2000]
    Yellow Dot [Gorse-Logrippo-Sincennes-2005]
    Yellow Dot [Korver-1997]
    Yellow Dot [Stepien-Logrippo-1994]
    Yellow Dot [Stepien-Logrippo-1995]
    Yellow Dot [Turner-2003a]

Orange Dot grid computing:
    Yellow Dot [Tan-2009]
    Yellow Dot [Tan-Turner-2006]
    Yellow Dot [Tan-Turner-2007]

Orange Dot graphics standards:
    Yellow Dot [Purvis-1990]
    Yellow Dot [Reade-1992]

Orange Dot hardware design:
    Yellow Dot [Delgado-deMiguel-Robles-Rabay-Lopez-1993]
    Yellow Dot [Faci-Logrippo-1993a]
    Yellow Dot [Fernandez-Quemada-Vidaller-Miguel-1988]
    Yellow Dot [Joeli-Kol-2008]
    Yellow Dot [Salaun-Serwe-2005]
    Yellow Dot [Turner-Sinnott-1994a]

Orange Dot home networks:
    Yellow Dot [Turner-2010b]

Orange Dot medical devices:
    Yellow Dot [Thomas-1994a]
    Yellow Dot [Trafford-1997]
    Yellow Dot [Turner-2005e]

Orange Dot multimedia systems:
    Yellow Dot [Regan-1993]
    Yellow Dot [Sun-Yasumoto-Mori-Higashino-2003]

Orange Dot neural networks:
    Yellow Dot [Gibson-1993a]

Orange Dot object-oriented analysis and design:
    Yellow Dot [Gibson-1993a] [Cusack-Lai-1991]
    Yellow Dot [Gibson-1993a] [Hedlund-1993]
    Yellow Dot [Gibson-1993a] [Moreira-Clark-1996a]

Orange Dot ODP (Open Distributed Processing):
    Yellow Dot [ISO/IEC 10746-4]
    Yellow Dot [Sinnott-Turner-1995]
    Yellow Dot [vanSinderen-Pires-Vissers-1993]
    Yellow Dot [Vogel-1993]

Orange Dot performance analysis:
    Yellow Dot [Miguel-Fernandez-Vidaller-1992]
    Yellow Dot [Rico-vonBochmann-1991]
    Yellow Dot [Schieferdecker-1994]

Orange Dot program visualisation:
    Yellow Dot [Turner-McClenaghan-Chan-1996]
    Yellow Dot [Winstanley-Bustard-1991]

Orange Dot safety critical systems:
    Yellow Dot [Ernberg-Fredlund-Jonsson-1991]
    Yellow Dot [Garavel-Hautbois-1994]
    Yellow Dot [Thomas-Ormsby-1994]

Orange Dot telecommunications and voice services:
    Yellow Dot [Azcorra-Vazquez-AlvarezCampana-Vinyes-1993]
    Yellow Dot [Boumezbeur-Logrippo-1992]
    Yellow Dot [Dahl-Najm-1994]
    Yellow Dot [Ernberg-Hovander-Montfort-1992]
    Yellow Dot [Faci-Logrippo-1994]
    Yellow Dot [Gamble-1990]
    Yellow Dot [Leon-Carracedo-Moreno-etal-1994]
    Yellow Dot [Navarro-Martin-1990]
    Yellow Dot [Tilanus-Yang-1988].
    Yellow Dot [Turner-2003a]
    Yellow Dot [Turner-2003c]

Orange Dot web services:
    Yellow Dot [Ferrara-2004]
    Yellow Dot [Chirichiello-Salaun-2005]
    Yellow Dot [Salaun-Ferrara-Chirichiello-2004]
    Yellow Dot [Tan-2009]
    Yellow Dot [Turner-2005d]
    Yellow Dot [Turner-2007a]

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Last Update: 11th February 2022
URL: https://www.cs.stir.ac.uk/~kjt/research/well/well.html