J.A. de la Puente

BUILDING SAFETY-CRITICAL REAL-TIME SYSTEMS WITH REUSABLE CYCLIC EXECUTIVES

Abstract Many real-time systems have strict safety requirements, and concurrent processes cannot be used in their development. Thus, these safety-critical systems are developed using synchronous architectures based on cyclic scheduling. This paper describes a reusable cyclic executive implementation in Ada 95, based on a generic architecture for synchronous real-time systems. This generic architecture is described by means of an object-oriented design notation. New Ada characteristics, as well as exceptions and generics, are used to build the component blocks of this generic architecture. In order to develop real-time systems, guidelines for using these reusable components are also provided. Copyright

Real-time Software Development: A Perspective

Abstract The state of the art in concepts, methods and tools for the development of real-time software for control is reviewed. Established results and recent developments in models of real-time systems, design methods, programming languages and operating systems are described.

Schedulability analysis of AR-TP, a Ravenscar compliant communication protocol for high-integrity distributed systems

A new token-passing algorithm called AR-TP for avoiding the non-determinism of some networking technologies is presented. This protocol allows the schedulability analysis of the network, enabling the use of standard Ethernet hardware for hard real-time behavior while adding congestion management. It is specially designed for high-integrity distributed hard real-time systems, being fully compliant with the Ravenscar profile

Building reusable software architectures with Ada

A new method for building reusable generic software architectures from reusable software components is described in the paper. The method is based on the use of generic module parameters, and can be directly supported by language features only in Ada 95. In this way, we can have the compiler enforcing a system architecture and enable it to check for proper use of its components. An example is given which illustrates the application of the method to a simple real-time architecture.

A target code model for incremental prototyping

Abstract The software part of embedded real-time systems is constantly increasing in size and complexity. Therefore, for a company to stay competitive in a strong market, techniques for management of such risks as misunderstanding of customer needs, schedule or budget overrun, quality pitfalls, or in the worst case cancelled projects, are required. The spiral model guides a developer to postpone detailed elaboration of low-risk software elements until the essential high-risk elements of the design are stabilised. The spiral model incorporates prototyping as a risk reduction option at any stage of development. This means supporting executable system models where different parts are represented at different levels of abstractions called (distributed) heterogeneous prototypes. Source code is integrated into the system models through a run-time adaptation technology which is explained in this paper.

Building Safety-Critical Real-Time Systems with Reusable Cyclic Executives

Abstract Many real-time systems have strict safety requirements and concurrent processes cannot be used in their development. Thus, these safety critical systems are developed using synchronous architectures based on cyclic scheduling. This paper describes a cyclic executive reusable implementation in Ada95 based on a generic architecture for synchronous realtime systems. This generic architecture is described by means of an object-oriented design notation. New Ada characteristics, as well as exceptions and generics, are used to build the component blocks of this generic architecture. In order to develop real-time systems, guidelines to use these reusable components are provided too.

A TARGET CODE MODEL FOR INCREMENTAL PROTOTYPING

The software part of embedded real-time systems is constantly increasing in size and complexity. Therefore, for a company to stay competitive in a strong market, techniques for management of such risks as misunderstanding of customer needs, schedule or budget overrun, quality pitfalls, or in the worst case cancelled projects, are required. The spiral model guides a developer to postpone detailed elaboration of low-risk software elements until the essential high-risk elements of the design are stabilised. The spiral model incorporates prototyping as a risk reduction option at any stage of development. This means supporting executable system models where different parts are represented at different levels of abstractions called (distributed) heterogeneous prototypes. Source code is integrated into the system models through a run-time adaptation technology which is explained in this paper.

An environment for distributed prototyping of real-time systems

Abstract Designing and reasoning about real-time systems are difficult activities, in which timing and reactive behaviour requirements add significant complexity to system validation. In this paper, a new technique for distributed prototyping of real-time systems is presented. It enables system prototypes to be concurrently developed and tested by a geographically distributed team, in such a way that each developer can validate his or her part of the system against the other parts which are being built in other development sites. A set of tools has been implemented that supports validation of functional and time behaviour through distributed animation of graphical prototypes with a consistent vision of simulated time.