International Real-Time Ada Workshop Research Articles

Session Summary

This session of the 18th International Real Time Ada Workshop discussed the use of profiles in Ada, and the possibility and desirability of adding additional language profiles to Ada besides the Ravenscar Tasking Profile.

Session Summary

The first session of the 18th International Real Time Ada Workshop discussed two aspects of parallel programming in real-time systems, the use of executors in parallel systems, and syntax to guide the reduction of parallel computations to return a correct single answer. This report captures the discussions held and the decisions and recommendations of the workshop on these topics.

Update of ISO/IEC Technical Reports on the Use of the Ada Programming Language in High Integrity Systems

The Ada programming language has been designed for use in high integrity, safety critical, and secure software systems. Several International Organization for Standardization/International Electrotechnical Commission (ISO/IEC) technical reports have been developed to provide guidance on the appropriate use of Ada to achieve the largest benefit in the verification and security of high integrity systems. While the Ada programming language has been evolving over time, these technical reports were written utilizing the Ada 2005 version of the programming language standard. In this brief paper, we pose that the International Real-Time Ada Workshop membership assume the responsibility for updating the technical reports to be in alignment with the current Ada programming language standard, known as Ada 2012.

Session summary

The first session of the 18th International Real Time Ada Workshop discussed two aspects of parallel programming in real-time systems, the use of executors in parallel systems, and syntax to guide the reduction of parallel computations to return a correct single answer. This report captures the discussions held and the decisions and recommendations of the workshop on these topics.

Conclusions of the 14th international real-time Ada workshop

The last session of IRTAW-14 was devoted to concluding on the results of the workshop, with the goal of prioritizing and selecting Ada Issues (AIs) to be produced and sent to the ISO/IEC JTC1/SC22/WG9 Ada Rapporteur Group (ARG). It allowed time for closing some open issues. In this report, Sections 2 to 4 summarize the final discussion around some open issues. Section 5 reflects the list of AIs to be produced by the workshop. The plan for next meeting is considered in Section 6. There is a final consideration about concurrency vulnerabilities in Section 7. Finally, Section 8 concludes with the closing of IRTAW-14.

Session details: Proceedings of the 14th international real-time Ada workshop

Session details: Proceedings of the 14th international real-time Ada workshop

Session summary

The first session in the 12th International Real-Time Ada Workshop was a summary of the new core language features that are proposed for the Amendment to Ada that is scheduled for 2005.

Protected ceiling changes

The inclusion of dynamic ceiling priorities in Ada is a topic of discussion in the Real-Time Ada community. Several approaches have been discussed in previous editions of the International Real-Time Ada Workshop, which have allowed to identify the problems associated with this issue, mainly the interaction of such feature with tasking, consistency and efficiency of implementation. In this paper, a new approach for dynamic ceilings is presented. It is based on implementing the ceiling change as a predefined protected operation itself, which allows to eliminate the potential for data corruption that other approaches introduce, without the need for additional locks.The paper also discusses the use of the proposed operation in the context of mode changes.

SimpleGraphics

Visualization of complex software applications is an exciting and challenging field. Useful displays are invaluable for developers in analysis of their software systems, and for meaningful system presentations to customers at a higher conceptual level.There have been many notable visualization examples applicable to data centric systems, including the GRASP code visualizer[11], the UW Illustrating Compiler[14], and the Information Space Visualizations embodied in Cone Trees[7] and Data Walls[8]. As conceptual and abstraction levels of these advanced graphics increases and becomes more prevalent, and as the real-world applications become more complicated from concurrency and distribution, the interfacing cohesion process becomes more difficult.This paper describes concepts and issues for integrating visualization techniques into multi-threaded and distributed applications, and shows foundation use available across application domains. SimpleGraphics is a term used in this paper to describe these powerful and rapidly developed visualizations applied to soft real-time applications. For the applications described here to meet the "simple" criteria they must be both conceptually simple and quickly developed - in say under 10 minutes. This leads to their use when appropriate in a "what if" manner, as well as taking them out if no longer needed. Looking ahead, the newer embedded devices, such as the AutoPC or the PalmPilot, have a small graphic foot print and will probably not allow for complicated graphics, leading to more use of abstractions like SimpleGraphics. Newer object oriented concurrency and distribution abstractions are being explored and applied to augment the work since the last International Real-Time Ada Workshop (IRTAW)[6][5]. With pervasive concurrent and distributed systems under development, it becomes clear that better controls and visualizations techniques are necessary, and Ada provides elegant solution techniques that can evolve with changing requirements. The graphic language, Tcl/Tk[9], is used here both for it's portability and its higher abstraction (through less syntax) supporting rapid development feedback.The benefits and impacts from this work include highlighting multi-threaded real-time issues, showing rapid turnaround through reuse, robust development through objects, better visualization techniques, and techniques for interfacing to other languages. In short, the goals of the 9th IRTAW are addressed in various aspects within this body of work.

Adapting Ada distribution and fault tolerance

During the Third International Real Time Ada Workshop held at Nemacolin Woodlands, Pennsylvania, in June 1989, the present authors formed a study group to review the changes in the Ada standard which would make the language more suitable for programming distributed systems. It was accepted that one of the important advantages of distributing embedded systems was the potential for recovery from partial failure of hardware, and that the techniques of programming recovery from such failure were not well supported by the current form of Ada. The working group made specific proposals, which have since been refined at a further meeting and discussions by electronic mail. The present paper reviews the causes of difficulty, and then outlines the new proposals, explaining their rationale in relation to the identified requirements.