On the testability of distributed real-time systems

Schütz, Werner

doi:10.1109/reldis.1991.145404

Cited by 19 publications

(16 citation statements)

References 17 publications

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“…Over the past three decades, advent of fast processors, sophisticated computer modelling with graphics, and advances in network technology have gone into building of simulation technology that is just a little short of the reality. Other pertinent advantages provided by the simulator are time flexibility, training, repeatability and the deep insight into the functionality of systems it mimics 4 .…”

Section: Testing Of Real-time Softwarementioning

confidence: 99%

Range Safety Real-time System for Satellite Launch Vehicle Missions–Testing Methodologies

Varaprasad¹,

Rao²

2006

DSJ

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A real-time system plays a critical role in the range safety decision-making in a satellite launch mission. Real-time software, the heart of such systems, is becoming an issue of criticality. Emphasis is being laid on the development of reliable, robust, and operational system. This paper purports to delineate prudent testing methodologies implemented to test the real-time system.Keywords: Real-time system, range safety, inertial navigation system, polynomial filter, Kalman filter, testing, network simulations . INTRODUCTIONA real-time system (RTS) in a satellite launch mission helps the range safety officer to monitor the behaviour of the vehicle at each instant after the lift-off. Abnormal deviant behaviour of the vehicle entails its destruction during mid-flight. This flight monitoring and mission-abort action preempts loss of precious human lives and property. Radars around the launch site as well as down the range, and telemetry from onboard systems provide range safety officer with data describing position, velocity, instantaneous impact point and performance of onboard systems to enable to execute requisite action within the specified time. A well-designed, systematically developed, and thoroughly tested real-time system is of utmost necessity for the mission. Towards this end, prudent testing methodologies are implemented at the Satish Dhawan Space Centre [SDSC SHAR], which are simple, cost-effective, flexible, and repeatable in their scope. . DESCRIPTION OF REAL-TIME SYSTEMThe range safety real-time system is a timetriggered RTS that offers predictable execution of hard real-time tasks even under peak-load conditions. The following salient features have influenced the design of this RTS:•

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Section: Testing Of Real-time Softwarementioning

confidence: 99%

Range Safety Real-time System for Satellite Launch Vehicle Missions–Testing Methodologies

Varaprasad¹,

Rao²

2006

DSJ

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“…We call such real-time system dynamic RTS. The drawback of dynamic RTSs is that they are inherently harder to test than static RTSs [13]. The major reason is that execution of a dynamic RTS is decided by the often unpredictable environment while execution of a static RTS is decided by time.…”

Section: Introductionmentioning

confidence: 99%

Testability of Dynamic Real-Time Systems: An Empirical Study of Constrained Execution Environment Implications

Lindström

Offutt

Andler

2008

2008 International Conference on Software Testing, Verification, and Validation

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Real-time systems must respond to events in a timely fashion; in hard real-time systems the penalty for a missed deadline is high. It is therefore necessary to design hard real-time systems so that the timing behavior of the tasks can be predicted. Static real-time systems have prior knowledge of the worst-case arrival patterns and resource usage. Therefore, a schedule can be calculated off-line and tasks can be guaranteed to have sufficient resources to complete (resource adequacy). Dynamic real-time systems, on the other hand, do not have such prior knowledge, and therefore must react to events when they occur. They also must adapt to changes in the urgencies of various tasks, and fairly allocate resources among the tasks. A disadvantage of static real-time systems is that a requirement on resource adequacy makes them expensive and often impractical. Dynamic realtime systems, on the other hand, have the disadvantage of being less predictable and therefore difficult to test. Hence, in dynamic systems, timeliness is hard to guarantee and reliability is often low. Using a constrained execution environment, we attempt to increase the testability of such systems. An initial step is to identify factors that affect testability. We present empirical results on how various factors in the execution environment impacts testability of real-time systems. The results show that some of the factors, previously identified as possibly impacting testability, do not have an impact, while others do.

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“…• Guidelines on how to design component based software for testability can be found in [15]. • Testability in the real-time domain is discussed in [33].…”

Section: 2: Testability Improvementmentioning

confidence: 99%

Identifying test-critical dependencies

Jungmayr

International Conference on Software Maintenance, 2002. Proceedings.

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Regression testing is a major cost driver during software maintenance. An important approach to reduce maintenance costs is therefore to improve software testability. The improvement efforts should concentrate on those parts of a software system that cause the most severe problems during testing and maintenance.This paper describes a new approach to testability improvement focusing on system structure. We identify dependencies that are critical for testing, i.e. test-critical dependencies, based on a set of testability metrics. The results of four case studies show that 1) a small subset of the dependencies within a system has an exceedingly high impact on particular testability metrics, 2) conventional coupling metrics are not good predictors of these test-critical dependencies, 3) dependencies automatically identified to be test-critical are good indicators of design that needs improvement.

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On the testability of distributed real-time systems

Cited by 19 publications

References 17 publications

Range Safety Real-time System for Satellite Launch Vehicle Missions–Testing Methodologies

Range Safety Real-time System for Satellite Launch Vehicle Missions–Testing Methodologies

Testability of Dynamic Real-Time Systems: An Empirical Study of Constrained Execution Environment Implications

Identifying test-critical dependencies

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