Verification and Validation in the Life-Cycle of Real-Time Software Development

Rapid advances in computer technology as hardware and software have provided the capability to develop complex real-time systems. While these advances have enabled significant increases in system efficiency and has allowed the development and operation of systems that were earlier impossible, it has also introduced the inherent drawback of system induced failures. In the real-time computing environment, for a complex system, the software components are highly interdependent and therefore identification and resolving software problems early in the life-cycle is necessary to prevent the probable catastrophic failures in actual utilization. In general, the software development cycle is divided into phases of requirements, implementation and testing. The basic objectives in verification and validation (V&V) of software requirements and design specifications are to identify and resolve problems and high-risk issues during the life-cycle of real-time software development. In this respect the real-time software requirements have to be carefully determined and they should comprise the following features.

1. a)

   Statement of the functions which software is expected to perform and the description of the required level of performance.

2. b)

   Overall architecture of the software product and its components.

3. c)

   Design specifications.

The V&V process involves the interrelations of the activities associated with the above features. In particular, verification is the process of determining if the products of a given phase of the software development cycle fulfill the requirements established during the previous phase. Validation in the process of evaluating software at the end of the software development process to ensure compliance with software requirements [1].

With respect to real-time computing, there are several important V&V issues in the design of real-time software system. One of the important features of real-time systems is the critical nature of the software execution speed with reference to external events. If the time is not available to complete a task, the execution fails unless appropriate measures are taken. A second critical feature of the real-time system is limited memory capacity. Real-time software typically can execute in an environment where the size of the program or the I/O data can exhibit problems. Having these critical features in mind, the consideration of the following V&V issues on the life cycle of real-time software development take an important place:

1. a)

   Consistency

2. b)

   Completeness

3. c)

   Reliability

4. d)

   Maintainability

5. e)

   Testability

6. f)

   Portability

Above, some concepts differ in hardware designs relative to their software counterparts. Reliability is one example as software reliability differs from hardware reliability. Another example is the verification and validation concept which takes different forms in hardware systems applications where it is rather difficult to establish a unique definition of V&V which applies to all engineering systems [2]. In this respect V&V is a concept which is not to be built in the hardware system as, however, the case is reverse for the concept of reliability. On the other hand, an independent V&V effort can be implemented on a software so that quality can be built into the software by means of provisons that the features, with respect to the above-stated items, of V&V issues are favorably implemented in the life-cycle of real-time software development.

Authors and Affiliations

1. Electrical Engineering Faculty, Istanbul Technical University, P.O. Box 17, Teknik Universite, 80191, Istanbul, Turkey

   Özer Ciftcioglu

Editors and Affiliations

1. Vakgroep Informatica, Rijksuniversiteit Groningen, Postbus 800, 9700 AV, Groningen, The Netherlands

   Wolfgang A. Halang

2. Fachbereich Elektrotechnik und Informationstechnik, FernUniversität Hagen, D-58084, Hagen, Germany

   Wolfgang A. Halang

3. Department of Computer and Information Science, New Jersey Institute of Technology, 07102, Newark, NJ, USA

   Alexander D. Stoyenko

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