The B method is a method of software development based on B, a tool-supported formal method based on an abstract machine notation, used in the development of computer software. [1] [2]
B was originally developed in the 1980s by Jean-Raymond Abrial [3] [4] in France and the UK. B is related to the Z notation (also originated by Abrial) and supports development of programming language code from specifications. B has been used in major safety-critical system applications in Europe (such as the automatic Paris Métro lines 14 and 1 and the Ariane 5 rocket). [5] [6] [7] It has robust, commercially available tool support for specification, design, proof and code generation.
Compared to Z, B is slightly more low-level and more focused on refinement to code rather than just formal specification — hence it is easier to correctly implement a specification written in B than one in Z. In particular, there is good tool support for this. The same language is used in specification, design and programming. Mechanisms include encapsulation and data locality.
Subsequently, another formal method called Event-B [8] [9] [10] has been developed based on the B-Method, support by the Rodin Platform. [11] [12] Event-B is a formal method aimed at system-level modelling and analysis. Features of Event-B are the use of set theory for modelling, the use of refinement to represent systems at different levels of abstraction, and the use of mathematical proof for verifying consistency between these refinement levels.
The B notation depends on set theory and first order logic in order to specify different versions of software that covers the complete cycle of project development.
In the first and the most abstract version, which is called Abstract Machine, the designer should specify the goal of the design.
The B-Toolkit [13] [14] is a collection of programming tools designed to support the use of the B-Tool, [15] is a set theory-based mathematical interpreter, for the purposes of supporting the B-Method. Development was originally undertaken by Ib Holm Sørensen and others, at BP Research and then at B-Core (UK) Limited. [16]
The toolkit uses a custom X Window Motif Interface [17] for GUI management and runs primarily on the Linux, Mac OS X and Solaris operating systems.
The B-Toolkit source code is now available. [18]
Developed by ClearSy, Atelier B [19] [20] is an industrial tool that allows for the operational use of the B Method to develop defect-free proven software (formal software). Two versions are available: 1) Community Edition available to anyone without any restriction; 2) Maintenance Edition for maintenance contract holders only. Atelier B has been used to develop safety automatisms for the various subways installed throughout the world by Alstom and Siemens, and also for Common Criteria certification and the development of system models by ATMEL and STMicroelectronics.
The Rodin Platform is a tool that supports Event-B. [8] [21] [11] Rodin is based on an Eclipse software IDE (integrated development environment) and provides support for refinement and mathematical proof. The platform is open source and forms part of the Eclipse framework It is extendable using software component plug-ins. The development of Rodin has been supported by the European Union projects DEPLOY (2008–2012), RODIN (2004–2007), and ADVANCE (2011–2014). [8]
BHDL provides a method for the correct design of digital circuits, combining the advantages of the hardware description language VHDL with the formality of B. [22]
APCB (French : Association de Pilotage des Conférences B, the International B Conference Steering Committee) has organized meetings associated with the B-Method. [23] It has organized ZB conferences with the Z User Group and ABZ conferences, including Abstract State Machines (ASM) as well as the Z notation.
The following conferences have explicitly included the B-Method and/or Event-B:
The Z notation is a formal specification language used for describing and modelling computing systems. It is targeted at the clear specification of computer programs and computer-based systems in general.
The Vienna Development Method (VDM) is one of the longest-established formal methods for the development of computer-based systems. Originating in work done at the IBM Laboratory Vienna in the 1970s, it has grown to include a group of techniques and tools based on a formal specification language—the VDM Specification Language (VDM-SL). It has an extended form, VDM++, which supports the modeling of object-oriented and concurrent systems. Support for VDM includes commercial and academic tools for analyzing models, including support for testing and proving properties of models and generating program code from validated VDM models. There is a history of industrial usage of VDM and its tools and a growing body of research in the formalism has led to notable contributions to the engineering of critical systems, compilers, concurrent systems and in logic for computer science.
A specification language is a formal language in computer science used during systems analysis, requirements analysis, and systems design to describe a system at a much higher level than a programming language, which is used to produce the executable code for a system.
In computer science, formal methods are mathematically rigorous techniques for the specification, development, analysis, and verification of software and hardware systems. The use of formal methods for software and hardware design is motivated by the expectation that, as in other engineering disciplines, performing appropriate mathematical analysis can contribute to the reliability and robustness of a design.
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An entity–relationship model describes interrelated things of interest in a specific domain of knowledge. A basic ER model is composed of entity types and specifies relationships that can exist between entities.
Jean-Raymond Abrial is a French computer scientist and inventor of the Z and B formal methods.
In computer science, formal specifications are mathematically based techniques whose purpose are to help with the implementation of systems and software. They are used to describe a system, to analyze its behavior, and to aid in its design by verifying key properties of interest through rigorous and effective reasoning tools. These specifications are formal in the sense that they have a syntax, their semantics fall within one domain, and they are able to be used to infer useful information.
The Z User Group (ZUG) was established in 1992 to promote use and development of the Z notation, a formal specification language for the description of and reasoning about computer-based systems. It was formally constituted on 14 December 1992 during the ZUM'92 Z User Meeting in London, England.
BCS-FACS is the BCS Formal Aspects of Computing Science Specialist Group.
Egon Börger is a German-born computer scientist based in Italy.
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Michael J. Butler is an Irish computer scientist. As of 2022, he is professor of computer science and Dean of the Faculty of Engineering and Physical Sciences at the University of Southampton, England.
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Professor Martin C. Henson FBCS FRSA is an English computer scientist based at the University of Essex. He is dean for international affairs and is affiliated to the School of Computer Science & Electronic Engineering. Henson was head of the department of computer science from 2000 to 2006.
Charles Carroll Morgan is an American computer scientist who moved to Australia in his early teens. He completed his education there, including a Doctor of Philosophy (Ph.D.) degree from the University of Sydney, and then moved to the United Kingdom in the early 1980s. In 2000, he returned to Australia.
The Rodin tool is a software tool for formal modelling in Event-B. It was developed as part of several collaborative European Union projects, including initially the RODIN project (2004–2007).
Dansk Datamatik Center (DDC) was a Danish software research and development centre that existed from 1979 to 1989. Its main purpose was to demonstrate the value of using modern techniques, especially those involving formal methods, in software design and development.
Kenneth ("Ken") Arthur Robinson was an Australian computer scientist. He has been called "The Father of Formal Methods in Australia".