Software environment for integrating critical real-time control systems

Abstract

In the recent few years, integration of multiple real-time control modules has gained increased acceptance in the industry. Such integration can achieve lower overall hardware costs and reduced level of spares by sharing hardware resources among multiple applications. Single contemporary CPU can now harbor several applications which have been traditionally running on several older and slower computing platforms. However, the integrated approach faces new challenges such as the reusability of existing software and the prevention of fault propagation. The reuse of legacy application code, with minimal modifications, is strongly desirable since the cost of application re-development can be prohibitive. Resource sharing introduces dependencies among applications and thus requires additional design precautions to ensure that the effect of a failure in one application will not spread and impact other applications. This paper describes a two-layer software architecture, which enables the integration of multiple real-time applications while maintaining strong spatial and temporal partitioning among application modules. At the lower layer, a system executive creates multiple virtual machines. Each module accommodates an application with its choice of a real-time operating system. This architecture allows the reusability of existent software modules by enabling the integration of applications written for different real-time operating systems. The paper also addresses some issues related to the inter-application communication and to the handling of I/O devices. (C) 2004 Elsevier B.V. All rights reserved.