Meanings for Lotos
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 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.
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:
Language Of Temporal Ordering Specification (officially)
Lots Of Terribly Obscure Symbols
Let's Obfuscate This Obvious Specification
Language Of Thousands Of Styles
LOTOS also has some amusing anagrams in English:
LOTS O' (since Lotos has lots o' good ideas)
O, LOST! (as said to or by Lotos beginners)
SOTOL (a lily-like plant resembling the Lotos)
STOOL (a portable support for specifiers)
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.
Brussels University (BE)
ENST (Ecole National Supérieur des Télécommunications, FR)
Erlangen-Nürnberg University (DE)
ESTEC (European Space Technology Centre, NL)
Glasgow University (UK)
GMD (Gesellschaft für Mathematik und Datenverarbeitung, now Fraunhofer Fokus, DE)
Helsinki University (FI)
INRIA Rhône-Alpes (FR)
Liège University (BE)
Lisbon New University (PT)
Polytechnic University of Madrid (ES)
Ottawa University (CA)
Pisa National Research Council (IT)
Osaka University (JP)
Royal Holloway and Bedford New College (UK)
Santa Catarina Federal University (BR)
SERI (Software Engineering Research Institute, KR)
Stirling University (UK)
Sussex University (UK)
SICS (Swedish Institute of Computer Science, SE)
Twente University (NL)
Ulster University (UK)
Lotos-related projects known to the author to have web pages are as follows:
ANISE (Architectural Notions in Service Engineering, UK)
CONFORMED (Conformed of Radiological/Medical Devices, UK)
CRESS (Communication Representation Employing Systematic Specification, UK)
DIET (Developing Implementation and Extending Theory - A Symbolic Approach to Reasoning about Lotos, UK)
DILL (Digital Logic in Lotos, UK)
EASEL (Evaluating And Standardising Enhanced Lotos, UK/ES)
EUCALYPTUS/INRIA Rhône-Alpes (FR)
FORMOSA (Formalisation of ODP Systems Architecture, UK)
Further Verification Techniques for Lotos (UK)
MUSTARD (Multiple-Use Specification Testing and Refusal Description, UK)
SPLICE (Specification using Lotos for an Interactive Customer Environment, UK)
Temporal Aspects of Verification of Lotos Specifications (UK)
Verification Techniques for Lotos (UK)
VASY (Validation of Systems, FR)
INRIA Rhône-Alpes VASY (FR):
CADP (Cæsar Aldébaran Development Package)
TRAIAN (E-Lotos Compiler - currently excluding behaviour)
Polytechnic University of Madrid (ES):
Topo (Toolset for Product Realisation with Lotos)
University of Stirling (UK)
University of Twente (NL):
SMILE (SyMbolic Interactive Lotos Execution) - ftp directory
Major publications about Lotos include:
Tommaso Bolognesi, Jeroen van de Lagemaat and Chris A. Vissers, editors. The LotosPHERE Project. Kluwer Academic Publishers, London, UK, 1995.
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.
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.
ISO. Information Technology - Enhancements to Lotos (E-Lotos). ISO/IEC 15437, International Organisation for Standardization, Geneva, Switzerland, 2001.
ISO. Information Processing Systems - Open Distributed Processing - ELotos - Extended Lotos. Committee Draft, International Organisation for Standardization, Geneva, Switzerland, May 1998.
Kenneth J. Turner, editor. Using Formal Description Techniques - An Introduction to Estelle, Lotos and SDL. Wiley, New York, USA, January 1993.
Online material includes:
Lotos Bibliography (online)
Lotos Bibliography (BibTeX)
Lotos Course for Users
Lotos News (somewhat dated)
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:
INRIA Rhône-Alpes (FR):
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.
CIM (Computer Integrated Manufacturing):
DTP (Distributed Transaction Processing):
object-oriented analysis and design:
ODP (Open Distributed Processing):
safety critical systems:
telecommunications and voice services:
Up one level to Ken Turner ResearchLast Update: 9th February 2011