We have developed an early prototype of an ARINC 653 implementation using the virtualization technology of the open source Xen hypervisor along with a Linux-based domain/partition OS. In this paper we share lessons learned from adding to our prototype both an ARINC 653 CPU scheduler and a simple ARINC 653 serial I/O driver. By using a common hypervisor technology on multiple platforms, early application development can be done in a PC environment with relatively good modeling of the final target's behavior. The paper covers three topics. First, we start with an overview of the ARINC 653 standard, which is important because it reduces development costs, reduces system weight, and lowers certification costs. The standard focuses on resource partitioning of time and space on an avionics computer, managing the three primary subsystems of the computer: Central Processing Unit (CPU), Memory, and Input/Output (I/O). Second, we will review virtualization technology, an established method of sharing a computing resource, considering it for adaptation to ARINC 653. Third, as a case study, we will examine our prototype implementation of the ARINC 653 standard using the Xen open source hypervisor. We conclude with a discussion of our plans for future work towards ARINC 653 simulation and development environments on both PC desktop and embedded targets.

ARINC 653 hypervisor

Model-based and component-oriented software development approaches are slowly superseding traditional ways of developing embedded systems. For investigating to which extent model-based development is feasible for embedded system development, we conducted a case study in which a small embedded system is developed using the MARMOT approach. In order to evaluate the degree of reuse that might be achieved, the components of the case study are used in the context of different small projects. Several aspects of reuse, application size, ease of adaptation, and development effort are quantified. This analysis reveals that model-based and component-oriented development performs well for small embedded systems, and it leads to the conclusion that model-driven/component-based development of embedded systems enables adaptable applications with higherthan- normal reuse rate. Preprint accepted for publication in 33rd EUROMICRO Conference on Software Engineering and Advanced Applications, 2007, IEEE Computer Society.

/pdf/applying-a-model-based-approach-for-embedded-system-20efvdpi81.pdf

Applying a Model-Based Approach for Embedded System Development

Model-based and component-oriented software development approaches are slowly superseding traditional ways of developing embedded systems. For investigating to which extent model-based development is feasible for embedded system development, we conducted a case study in which a small embedded system is developed using the MARMOT approach. In order to evaluate the degree of reuse that might be achieved, the components of the case study are used in the context of different small projects. Several aspects of reuse, application size, ease of adaptation, and development effort are quantified. This analysis reveals that model-based and component-oriented development performs well for small embedded systems, and it leads to the conclusion that model-driven/component-based development of embedded systems enables adaptable applications with higher- than-normal reuse rate.

/pdf/applying-a-model-based-approach-for-embedded-system-2zrvlqp7ac.pdf

Applying a Model-based Approach for Embedded System Development

Garbage collection has not been widely used in embedded real-time applications since traditional real-time garbage collection algorithm can hardly bound its worst-case responsiveness. To overcome this limitation, we have proposed a scheduling-integrated real-time garbage collection algorithm based on the single aperiodic server in our previous work. This paper introduces a new scheduling-aware real-time garbage collection which employs two aperiodic servers for garbage collection work. Our study aims at achieving similar performance compared with the single server approach whilst relaxing the limitation of the single server approach. In our scheme, garbage collection requests are scheduled using the preset CPU bandwidth of aperiodic server such as the sporadic server and the deferrable server. In the dual server scheme, most garbage collection work is serviced by the secondary server at low priority level. The effectiveness of our approach is verified by analytic results and extensive simulation based on the trace-driven data. Performance analysis demonstrates that the dual server scheme shows similar performance compared with the single server approach while it allows flexible system design.

Real-Time and Embedded Computing Systems and Applications

In this paper, we present the DIANA experiment on the use of Java in avionics safety critical applications. First, we discuss some concerns about the porting of the Java platform on the ARINC 653 operating system. Then the paper focuses on some important features of the Safety Critical Java Technology adopted in the project. Particular attention is turned on the Java memory model which is stack-based as opposed to the ongoing JSR-302 memory regions model. Benefits and issues of this approach are discussed through a real use case implementation representing part of a Flight Warning System.

Use of PERC Pico in the AIDA avionics platform

This paper presents the design of HIDOORS, an integrated development environment suitable for embedded distributed real-time systems, based on the Java programming language. HIDOORS will cover all the life-cycle of real-time software development with extensions to existing tools (UML modeling, Java compiler Java Virtual Machine, and a worst case execution time analysis tool) that will all be integrated into a single integrated development environment. The system will also assist the developer in distributing the application, by providing faster RMI and a distributed event manager that provides strict timing guarantees. This paper is written at the beginning of HIDOORS development, and as such, it presents only, the defined objectives and the early, architecture of the system; further developments will be the Subject of future works.

HIDOORS - a high integrity distributed deterministic Java environment

The paper presents a generic framework to analyse the timing behavior of protocol graphs derived from the composition of micro-protocols. The model assumes that a protocol stack is composed of a set of protocol objects that interact through the exchange of events. A specific task is associated with each relevant protocol event and for each task, the periods and offsets are derived from a description of the interactions between adjacent protocols. To illustrate the use of the model, a stack of modular reliable group communication protocols for the CAN field-bus is analysed.

/pdf/response-time-analysis-of-composable-micro-protocols-3mbt7ils24.pdf

Response time analysis of composable micro-protocols

This paper presents the design of RT-Appia, a framework for the development and implementation of configurable real-time protocol stacks. The goal of RT-Appia is to allow the construction of specialized protocols through the composition of pre-defined micro-protocols. RT-Appia attempts to balance the flexibility and efficiency of micro-protocols with the predictability requirements of real-time applications.

The design of RT-Appia

The design of RTAppia

A flexible way of building modular communication stacks relies on the use of protocol composition. This paper describes a protocol composition framework that simplifies the task of deriving the worst-case response time of a protocol composition from the protocol implementation. In order to derive the worst-case response time of a protocol composition, one needs to capture its event-graph: the event-graph consists of the set of all events processed by each component and the relation between those events. The framework, called RT-Appia, takes a pragmatic approach: instead of requiring the use of domain specific code analysis tools, or dedicated compilers, it simply requires protocol programmers to make explicit which events are processed and produced by each layer, and how these events are related. An interesting aspect of the approach is that the same data structures that are used to simplify the task of computing the worst-case response time of the protocol composition are also used to optimize the performance and to debug the resulting implementation.

J. Ventura

Papers

HIDOORS - a high integrity distributed deterministic Java environment

Response time analysis of composable micro-protocols

The design of RT-Appia

The design of RTAppia

Implementation and analysis of real-time communication protocol compositions