Title :
Requirements-based monitors for real-time systems
Author :
Peters, Dennis K. ; Parnas, David Lorge
Author_Institution :
Fac. of Eng. & Appl. Sci., Memorial Univ. of Newfoundland, St. John´´s, Nfld., Canada
fDate :
2/1/2002 12:00:00 AM
Abstract :
Before designing safety- or mission-critical real-time systems, a specification of the required behavior of the system should be produced and reviewed by domain experts. After the system has been implemented, it should be thoroughly tested to ensure that it behaves correctly. This is best done using a monitor, a system that observes the behavior of a target system and reports if that behavior is consistent with the requirements. Such a monitor can be used both as an oracle during testing and as a supervisor during operation. Monitors should be based on the documented requirements of the system. If the target system is required to monitor or control real-valued quantities, then the requirements, which are expressed in terms of the monitored and controlled quantities, will allow a range of behaviors to account for errors and imprecision in observation and control of these quantities. Even if the controlled variables are discrete valued, the requirements must specify the timing tolerance. Because of the limitations of the devices used by the monitor to observe the environmental quantities, there is unavoidable potential for false reports, both negative and positive, This paper discusses design of monitors for real-time systems, and examines the conditions under which a monitor will produce false reports. We describe the conclusions that can be drawn when using a monitor to observe system behavior
Keywords :
formal specification; program testing; real-time systems; safety-critical software; system monitoring; documented requirements; environmental quantities; errors; false reports; imprecision; mission-critical real-time systems; oracle; requirements-based monitors; safety-critical real-time systems; specification; supervisor; testing; timing tolerance; Computer displays; Control systems; Error correction; Mission critical systems; Monitoring; Real time systems; Safety devices; System testing; Terminology; Timing;
Journal_Title :
Software Engineering, IEEE Transactions on