Evaluating Embedded-Software Specifications -- Quantitative and Structured Assessment of Declarative Interface Descriptions

Formal methods for software development receive much attention in research centres, but are rarely used in industry for the development of (large) software systems. One of the reasons is that little is known about the integration of formal methods in the software process, and the exact role of formal methods in the software life-cycle is still unclear. In this paper, a detailed examination is made of the application of, and the benefits resulting from, a generally applicable formal method (VDM) in a standard model for software development (DoD-STD-2167A). Currently, there is no general agreement on how formal methods should be used, but in order to analyse the use of formal methods in the software process, a clear view of such use is essential. Therefore, we show what is meant by ‘using a formal method’. The different activities of DoD-STD-2167A are analysed with regard to their suitability for applying VDM and the benefits that may result from applying VDM for that activity. Based on this analysis, an overall view on the usage of formal methods in the software process is formulated.

Starting from the experience gained in organizing TAPSOFT'85, the paper discusses the place of formal methods in software development. It distinguishes two notions of theory: the mathematical science of computation and the treatment of computing as a human activity. An adequate software theory needs to take both theoretical perspectives into account. Therefore, the paper explores the borderline of formalization and human activity in several directions: concerning the role and scope of formalized procedures, the relation between formal models and situated use, the process of learning in software development and the ways computer programs become effective in use. Fundamental assumptions underlying formal methods and their relation to emancipatory approaches such as participatory design are discussed. The paper closes with calling for a dialogical framework for further pursuing these questions.

The benefits of formal methods in software development are well recognised and well documented. Design recovery involves analysing the source code and recovers the desired design elements based on design recovery specification. One way to ensure the correctness of the recovered design is to use formal methods in the process. This paper describes an approach to apply formal methods to design recovery. We present the Concept Mapping Language (CML), which is largely based on an adapted form of first-order languages with an object-oriented syntactical extension, to specify the recovery specification that guides the design recovery process. CML enforces consistency in the specification through formal notations and syntax, and the formal specification ensures correctness in the recovered design through formally correct specification. The result is a simple and reliable approach to apply formal methods to design recovery that will ensure correctness in the specification and therefore the recovered design.

The proper use of formal methods in software development strongly influences the nature and relationships between the various kinds of documentation produced. Rather than being a mass of heterogeneous information produced mainly for immediate use and then discarded, product documentation should be a coherent collection of information of lasting value in the continuing life of the product. In this paper we look first at the nature of product documentation in a mature product developed with the aid of formal methods. Next we consider how different people in a software development organisation interact with product documentation in their work. Finally we examine the problems that face managers of existing products who wish to construct product documentation in the mould described here.

An integration of traditional verification techniques and formal specifications in software engineering is presented. Advocates of such techniques claim that mathematical formalisms allow them to produce quality, verifiably correct, or at least highly dependable software and that the testing and maintenance phases are shortened. Critics on the other hand maintain that software formalisms are hard to master, tedious to use and not well suited for the fast turnaround times demanded by industry. In this paper some popular formalisms and the advantages of using these during the early phases of the software development life cycle are presented. Employing the Floyd-Hoare verification principles during the formal specification phase facilitates reasoning about the properties of a specification. Some observations that may help to alleviate the formal-methods controversy are established and a number of formal methods successes is presented. Possible conditions for an increased acceptance of formalisms in oftware development are discussed.

Model checking of safety-critical software in the nuclear engineering domain

Industrial usage of code analysis tools based on semantic analysis, such as the Frama-C platform, poses several challenges, from the setup of analyses to the exploitation of their results. In this paper, we discuss two of these challenges. First, such analyses require detailed information about the code structure and the build process, which are often not documented, being part of the implicit build chain used by the developers. Unlike heuristics-based tools, which can deal with incomplete information, semantics-based tools require stubs or specifications for external library functions, compiler builtins, non-standard extensions, etc. Setting up a new analysis has a high cost, which precludes industrial users from trying such tools, since the return on investment is not clear in advance: the analysis may reveal itself of little use w.r.t. the invested time. Improving the usability of this first step is essential for the widespread adoption of formal methods in software development. A second aspect that is essential for successful analyses is understanding the data and navigating it. Visualizing data and rendering it in an interactive manner allows users to considerably speed up the process of refining the analysis results. We present some approaches to both of these issues, derived from experience with code bases given by industrial partners.

Specifications are important in software development because a large percentage of the errors at implementation and test phases are traceable to a lack of precision of the specifications. Formal methods are studied and applied to produce clear specifications and argue about them rigorously. As formal methods may even increase the ratio of specification phase in the software life-cycle, it is necessary to be efficient in debugging, modification, and reuse of specifications to reduce cost of the whole software development process. In a large scale specification in particular, parts extracted from the specification are useful. We introduce here a specification slicing that supports debugging, modification and reuse of specifications. In this paper, we define specification slice as a part of a specification that defines or restricts values of a particular variable used in the specification. Attention is also directed to applications of specification slicing and support tools. >

Clean room software engineering is a formal software development method that can strictly engineer software development and eliminate defects before they can cause serious harm. The clean room software engineering model has its own advantages and disadvantages in use. To use it in traditional software engineering, it is necessary to clarify the relationship between it and traditional software engineering methods and practices. Based on the technology and principles of the clean room software process, this paper gets the advantages and disadvantages of the clean room. Corresponding the traditional method-based software process to the key technology of the clean room, making the traditional management-based software engineering method and the tailored clean room compatible, and the software engineering practice of the clean room software process is compared with the traditional software engineering practice. To discuss the clean room and traditional software engineering, in order to expand the use of clean room methods, improve the clean room software process, and improve the quality of software.

Specification and Verification of Safe Software Systems

This paper introduces a new approach of using automata to model behaviour of objects. Automata allow to design a software model on the abstract level of states and transitions. We make precise the meaning of states and transitions in the context of objects and types. This formal semantics serves as a link between informal and formal software development methods. Second, we give a formal, but nevertheless intuitive definition of automata specialization which not only provides a way for reuse of type definitions in subtypes, but also shows how to incrementally design types through refinement. Third we define the notion of a role an object takes when viewed from the environment. Then we can give a formal, but short proof that our definitions satisfy the subtype requirement, that means that an object of the subtype plays the roles of its Supertypes.

The Use of Analytic Hierarchy Process for Software Development Method Selection: A Perspective of e-Government in Indonesia

MEMOCODE brings together researchers and practitioners interested in formal methods for system design and development to exchange research results and lessons learned. The conference focuses on the foundations and applications of formal methods in the development of hardware, firmware, middleware, and application software for systems ranging from single embedded devices to highly networked cyber-physical systems and the Internet of Things.

The application of formal methods in the development of safety-critical embedded software is recommended in order to provide strong guarantees about the absence of software errors. In this context, WCET estimation tools constitute an important element to be formally verified. We present a formally verified WCET estimation tool, integrated to the formally verified CompCert C compiler. Our tool comes with a machine-checked proof which ensures that its WCET estimates are safe. Our tool operates over C programs and is composed of two main parts, a loop bound estimation and an Implicit Path Enumeration Technique (IPET)-based WCET calculation method. We evaluated the precision of the WCET estimates on a reference benchmark and obtained results which are competitive with state-of-the-art WCET estimation techniques.

MEMOCODE brings together researchers and practitioners interested in formal methods for system design and development to exchange research results and lessons learned. The conference focuses on the foundations and applications of formal methods in the development of hardware, firmware, middleware, and application software for systems ranging from single embedded devices to highly networked cyber-physical systems and the Internet of Things.